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Code Editor : gnuplot.gih

?gnuplot
?copyright
?license
     Copyright (C) 1986 - 1993, 1998, 2004, 2007  Thomas Williams, Colin Kelley

Permission to use, copy, and distribute this software and its
 documentation for any purpose with or without fee is hereby granted,
 provided that the above copyright notice appear in all copies and
 that both that copyright notice and this permission notice appear
 in supporting documentation.

Permission to modify the software is granted, but not the right to
 distribute the complete modified source code.  Modifications are to
 be distributed as patches to the released version.  Permission to
 distribute binaries produced by compiling modified sources is granted,
 provided you
   1. distribute the corresponding source modifications from the
    released version in the form of a patch file along with the binaries,
   2. add special version identification to distinguish your version
    in addition to the base release version number,
   3. provide your name and address as the primary contact for the
    support of your modified version, and
   4. retain our contact information in regard to use of the base software.
 Permission to distribute the released version of the source code along
 with corresponding source modifications in the form of a patch file is
 granted with same provisions 2 through 4 for binary distributions.

This software is provided "as is" without express or implied warranty
 to the extent permitted by applicable law.

AUTHORS
               Original Software:
                  Thomas Williams,  Colin Kelley.
               Gnuplot 2.0 additions:
                  Russell Lang, Dave Kotz, John Campbell.
               Gnuplot 3.0 additions:
                  Gershon Elber and many others.
               Gnuplot 4.0 and 5.0 additions:
                  See list of contributors at head of this document.
?introduction
?
 `Gnuplot` is a portable command-line driven graphing utility for Linux, OS/2,
 MS Windows, OSX, VMS, and many other platforms. The source code is copyrighted
 but freely distributed (i.e., you don't have to pay for it). It was originally
 created to allow scientists and students to visualize mathematical functions
 and data interactively, but has grown to support many non-interactive uses
 such as web scripting. It is also used as a plotting engine by third-party
 applications like Octave. Gnuplot has been supported and under active
 development since 1986.

Gnuplot supports many types of plots in either 2D and 3D. It can draw using
 lines, points, boxes, contours, vector fields, surfaces, and various
 associated text. It also supports various specialized plot types.

Gnuplot supports many different types of output: interactive screen terminals
 (with mouse and hotkey input), direct output to pen plotters or modern
 printers, and output to many file formats (eps, emf, fig, jpeg, LaTeX, pdf, png,
 postscript, ...). Gnuplot is easily extensible to include new output modes.
 Recent additions include interactive terminals based on wxWidgets (usable
 on multiple platforms), and Qt.  Mouseable plots embedded in web pages
 can be generated using the svg or HTML5 canvas terminal drivers.

The command language of `gnuplot` is case sensitive, i.e. commands and
 function names written in lowercase are not the same as those written in
 capitals. All command names may be abbreviated as long as the abbreviation is
 not ambiguous. Any number of commands may appear on a line, separated by
 semicolons (;). Strings may be set off by either single or double quotes,
 although there are some subtle differences.  See `syntax` and `quotes` for
 more details. Example:

set title "My First Plot";  plot 'data';  print "all done!"

Commands may extend over several input lines by ending each line but the last
 with a backslash (\).  The backslash must be the _last_ character on each
 line.  The effect is as if the backslash and newline were not there.  That
 is, no white space is implied, nor is a comment terminated.  Therefore,
 commenting out a continued line comments out the entire command
 (see `comments`).  But note that if an error occurs somewhere on a multi-line
 command, the parser may not be able to locate precisely where the error is
 and in that case will not necessarily point to the correct line.

In this document, curly braces ({}) denote optional arguments and a vertical
 bar (|) separates mutually exclusive choices.  `Gnuplot` keywords or `help`
 topics are indicated by backquotes or `boldface` (where available).  Angle
 brackets (<>) are used to mark replaceable tokens.  In many cases, a default
 value of the token will be taken for optional arguments if the token is
 omitted, but these cases are not always denoted with braces around the angle
 brackets.

For built-in help on any topic, type `help` followed by the name of the topic
 or `help ?` to get a menu of available topics.

A large set of demo plots is available on the web page
           http://www.gnuplot.info/demo/
 When run from command line, gnuplot is invoked using the syntax
       gnuplot {OPTIONS} file1 file2 ...
 where file1, file2, etc. are input file as in the `load` command.
 On X11-based systems, you can use
       gnuplot {X11OPTIONS} {OPTIONS} file1 file2 ...
 see your X11 documentation and `x11` in this document.

Options interpreted by gnuplot may come anywhere on the line.  Files are
 executed in the order specified, as are commands supplied by the -e option,
 for example
       gnuplot   file1.in   -e "reset"   file2.in

The special filename "-" is used to force reading from stdin.  `Gnuplot` exits
 after the last file is processed.  If no load files are named, `Gnuplot` takes
 interactive input from stdin.  See help `batch/interactive` for more details.
 The options specific to gnuplot can be listed by typing
       gnuplot --help
 See `command-line-options` for more details.

In sessions with an interactive plot window you can hit 'h' anywhere on the
 plot for help about `hotkeys` and `mousing` features.
 Section `seeking-assistance` will help you to find further information, help
 and FAQ.
?help-desk
?faq
?FAQ
?seeking-assistance
 The canonical gnuplot home page can be found at
           http://www.gnuplot.info

Before seeking help, please check file FAQ.pdf or the above website for a
           FAQ (Frequently Asked Questions) list.

Another resource for help with specific plotting problems (not bugs) is
           https://stackoverflow.com/questions/tagged/gnuplot

Bug reports and feature requests should be uploaded to the trackers at
           http://sourceforge.net/projects/gnuplot/support
 Please check previous reports to see if the bug you want to report has
 already been fixed in a newer version.

When reporting a bug or posting a question, please include full details
 of the gnuplot version, the terminal type, and the operating system.
 A short self-contained script demonstrating the problem is very helpful.

Instructions for subscribing to gnuplot mailing lists may be
 found via the gnuplot development website on SourceForge
           http://sourceforge.net/projects/gnuplot

Please note that before you write to any of the gnuplot mailing lists you
 must first subscribe to the list.  This helps reduce the amount of spam.

The address for mailing to list members is:
           gnuplot-info@lists.sourceforge.net

A mailing list for those interested in the development version of gnuplot is:
           gnuplot-beta@lists.sourceforge.net

?new
 These sections list new commands, plot styles, and other features introduced
 in version 5.4.
?new 64-bit_arithmetic
 *  All evaluation of expressions and functions uses 64-integer arithmetic if
    supported by the platform.
 *  Integer overflow is detected and handled according to user preference.
    See `overflow`.

?new voxels
 Gnuplot now supports operations based on 3D grids of voxel data.

*  `set vgrid $gridname size N` creates an NxNxN grid of voxels.
 *  `set vxrange [vxmin:vxmax]` together with `set vyrange` and `set vzrange`
    define which region of space the grid occupies.  This may or may not be
    identical to the xyz range of the plot.
 *  `voxel(x,y,z)` can be used in expressions to read or write an individual voxel.
 *  `vfill DATA_SOURCE using x:y:z:radius:(<expression>)` acts analogously to
    a plot command except that instead of plotting it increments voxels near each
    point in the input data.
 *  `vclear $gridname` resets an existing voxel grid to contain all zero values.
 *  the current contents of one or more voxel grids can be referenced by
    `splot` commands to assign colors or other properties of plot elements
    by using the `voxel` function in using specifiers.
    See demo `voxel.dem`.
 *  voxel grids can also be plotted by name in `splot` commands with plot styles
    `dots`, `points`, or `isosurface`.
    See demo `vplot.dem`.

?new plot_styles
 *  3D plot style `with polygons` reads polygon faces from a data file.
    This can be used to create a surface or to construct a solid object.
    See `with polygons`.
 *  `splot $voxelgrid with {dots|points}` marks all voxels whose value is above 
    a requested threshold level.
 *  `splot $voxelgrid with isosurface` creates a tessellated 3D surface enclosing
    voxels above a requested threshold level. See `isosurface`.
 *  Voxel grid values can be referenced in the `using` specifiers for 3D plots.
 *  `set spiderplot` selects a new plotting mode allowing creation of spider plots
    (also known as radar charts). These are essentially parallel axis plots where
    the axes are arranged radially rather than vertically.
    See `spiderplot`, `set style spiderplot`, `set paxis`. 
 *  Plot style `with circles` can be used in 3D plots.
 *  Plot style `with boxes` can be used in 3D plots.
 *  2D plot style `with arrows` is identical to `with vectors` except that each
    arrow is specified using x:y:length:angle rather than x:y:xdelta:ydelta
 *  splot FOO with pm3d fillcolor <colorspec>
 *  pm3d surfaces can have individual fillstyle and separate top/bottom fillcolor
 *  pm3d option `noclipcb` causes quadrangles with palette color outside cbrange
    to be skipped rather than being drawn with color clipped to cbmin or cbmax.
 *  Customized contour line types. See `set cntrparam`.

?new filters
 *  `smooth zsort` sorts 2D points on values in a 3rd column. See `smooth zsort`.

?new commands
 *  Voxel grid commands. See `set vgrid`, `set vxrange`, `vclear`, `vfill`,
    and `voxel`.
 *  New options for showing the xy xz and yz planes in 3D plots.
    See `set walls`, `set grid vertical`.
 *  `set table separator {tab|comma|"char"}` can be used to create csv files.
    See `plot with table`.
 *  New options `set view projection {xy|xz|yz}` adjust view angles, axis tic
    and label placement to generate a 2D projection of a 3D splot.
    `set view projection xy` is equivalent to `set view map`.
 *  `set rgbmax <value>` controls interpretation of input RGB values.
 *  Array size can be implicit if an initializer is present, e.g. `Array A = [1,2,3]`.
 *  Optional radial clipping of line segments in polar mode. See `set clip`.
 *  Extra lines to customize the key can be added by substituting `keyentry` in
    place of a filename or function in `plot` and `splot` commands.
    This produces a line in the key without generating a corresponding plot.
    See `keyentry`.
 *  User-specified translation of mouse coordinates (EXPERIMENTAL).
    See map_projection demo.
 *  `set datafile columnheaders` causes first line of input to be read as strings
    rather than as data values.  Equivalent to `set key autotitle columnheader`
    except that it does not affect generation of key entries.  If this option is
    in effect the `stats` command will generate an array of strings containing
    the column headers found.
 *  You can define multiple textbox styles. See `set style textbox`.

?new terminals
 *  The `pcl5` terminal has been extended to support PCL5e/PCL5c printers and
    many modern gnuplot features.
 *  The `pstricks` terminal has been extended to support many modern gnuplot
    features including RGB colors and transparency, filled polygons, and boxes.
 *  New terminal `pict2e` to use the LaTeX2e pict2e environment.
    It directly supersedes older terminals `latex`, `emtex`, `eepic`, and `tpic`,
    which are no longer built by default.
 *  The `texdraw` terminal has been extended to support text at arbitrary angles,
    variable line width, v5 dashed lines, and filled boxes and polygons. It can
    now be used with plain TeX, too.
 *  The previously experimental Direct2D variant of the `windows` terminal
    replaces the GDI and GDI+ variants. It now supports printing using D2D
    and color fonts.
 *  The `pm` OS/2 terminal has been modernized to support e.g. uft8, bold and
    italic text, and dashed lines. (Since 5.2.7).
 *  The `dospc` and `svga` DOS terminals have been modernized and now support
    interactive keyboard and mouse (svga only) input.

?new pixmaps
 *  `set pixmap` allows import of an image in standard format (png jpeg gif) as
    a pixmap that can be positioned anywhere in a plot or on the page.
    Unlike plotting `with image`, pixmap objects retain their original aspect
    ratio and size independent of axis scaling or rotation. See `pixmap`.

?new week-date_formats
 The Covid-19 pandemic of 2020/2021 generated increased interest in plotting
 epidemiological data, which is often tabulated using a "week date" reporting
 convention.  This revealed deficiencies with gnuplot support for this
 convention, including errors in time formats %W and %U.  These formats
 worked incorrectly prior to version 5.4.2.
 *  Time specifier format %W has been brought into accord with the
    ISO 8601 week date standard.
 *  Time specifier format %U has been brought into accord with the
    CDC/MMWR week date standard.
 *  New function `tm_week(time, std)` returns ISO or CDC standard week of year.
 *  New function `weekdate_iso(year, week, day)` converts ISO standard week date
    to calendar time.
 *  New function `weekdate_cdc(year, week, day)` converts CDC standard week date
    to calendar time.

?new other
 *  Enhanced text mode accepts \U+xxxx (xxxx is a 4 or 5 character hexadecimal)
    as representing a Unicode code point that is converted to the corresponding
    UTF-8 byte sequence on output.
 *  The character sequence $# in a `using` specifier evaluates to the total
    number of columns available in the current line of data.  For example
    "plot FOO using 0:(column($# - 1))" plots the last-but-one field of each row.
 *  Time/date input recognizes format %p to handle am/pm field
 *  plot titles are evaluated *after* plotting, rather than before. This allows
    the title to reference quantities calculated while plotting.
 *  Built-in modified Bessel functions (besi0 besi1 besin)
 *  Built-in order N Bessel functions of the 1st and 2nd kind (besjn besyn)

?new changes
 *  `pm3d filled area quadrangles` are clipped smoothly to current zrange.
    This affects pm3d surfaces and also the faces of 3D boxes, polygons, etc.
 *  Revised syntax for plot style 'with parallelaxes'. See `parallel`.
    The histogram, parallelaxis, and spiderplot styles now use similar syntax
    that can iterate over plot elements:
        `plot for [column=1:N] DATA using column`
 *  Sampling generated by pseudofile '+' is affected by `set trange`.
 *  Offsets from `set offsets` are applied only to autoscaled axes.
    The documentation has always said this, but it was not applied consistently.
 *  Imaginary values returned by the using specifier of a 2D plot are treated as
    undefined values (NaN) rather than as real(value).  This was always true for
    function plots and 3D data plots.  E.g. the following two plots are equivalent.
    plot [-1:1] sqrt(x); plot [-1:1] '+' using 1:(sqrt($1)
 *  The `set fontpath` command is deprecated. The search path for fonts to be
    embedded in output from the postscript terminal has been revised.
 *  3D plot style `with zerrorfill`. See `zerrorfill`, `fenceplots` and
   zerror demo.
 *  Beeswarm plots. See `set jitter`, `beeswarm` and
   beeswarm plot demo
 *  The symbol used for individual points in a plot can be controlled by data values
    (see `pointtype variable`)
 *  Normalized frequency of occurrence in a data set (see `smooth fnormal`)
 *  Automated binning of data (see `bins`)
 *  Polar coordinates may be used in label, arrow, and object definitions
 *  `set [m]ttics` places ticmarks and labels on the perimeter of a polar plot. See
 *  `set rlabel`  places a label above the r axis
 *  Inverted `rrange` (i.e. set rrange [90:0]) allows use of celestial horizontal
    coordinates. See
 *  `set border polar` draws a solid line around the perimeter of a polar plot
 *  `set theta` controls the position of theta = 0 around the perimeter of a
    polar plot and the sense (clockwise or anti-clockwise) of increasing theta
 *  Any plot axis can be assigned a pair of functions, possibly nonlinear, that
    describe the forward and reverse mapping to a linear range (see `set nonlinear`)
   Nonlinear x/y axis demo
 *  The familiar command `set logscale` has been reimplemented as a special case
    nonlinear axis where the paired functions are log(x) and exp(x).
 *  Inside the bracketed clause of an iteration, `continue` jumps immediately
    to the next iteration, `break` immediately exits from the iteration
 *  `toggle {<plotno> | "plottitle" | all}"` interactively enables or disables
    display of one element of the current plot (see `toggle`)
 *  `save fit` replaces deprecated command `update`
 *  `set table "outfile.name" append` will append subsequent tabulated plots to
    an existing text file rather replacing its contents
 *  `set pm3d lighting` describes a lighting model with specular highlighting
    (see `lighting`)
 *  `set minussign` tells gnuplot to use a special symbol in the current
    encoding to replace the ascii character '-' in negative numbers
 *  `set micro` tells gnuplot to use a special symbol in the current encoding to
    replace the ascii character 'u' for the scientific notation prefix "micro"
    The special typographic symbols for micro and minussign are used only in axis
    tic labels and strings explicitly created with gprintf(). The byte sequence
    used to represent these characters depends on the current encoding.
 *  This gnuplot version introduces a new data type `array name[size]`.
    An array must be declared before use. Each array element A[i] may be a string,
    an integer, a real number, or a complex value.  A single array may contain
    elements with different types.  The cardinality operator |A| returns the size
    of array A. See `arrays`.

*  See `sixelgd` for description of a new terminal that supports interleaving
    plots with the command lines that generated them if gnuplot is run inside a
    vt340-compatible terminal emulator
 *  The `domterm` terminal supports interleaving plots with the command lines
    that generated them if gnuplot is run inside an svg-aware terminal emulator
 *  The `windows` terminal supports saving the current graph to a bitmap file
 *  The `windows` terminal graph window can be docked to the wgnuplot text window
 *  New (experimental) Direct2D/DirectWrite backend for the `windows` terminal
 *  The `wxt` terminal supports exporting to an EMF file or printer on Windows
 *  The `dumb` terminal supports ANSI colors for lines and fill area
 *  The `tkcanvas` terminal has been rewritten to support many more modern gnuplot
    features, as well as new languages. (Since 5.0.3)

*  An additional rotation angle `azimuth` affects the orientation of 3D plots.
    This can be set from the command line (see `set view azimuth`) or by dragging
    with the right mouse button.
 *  gnuplot running under Windows can interpret Unicode (BMP) input scripts by
    converting them to the current encoding from `set encoding`, including UTF-8
 *  Textboxes can be assigned a border color and fill color (see `set style textbox`)
 *  Customized plot legends (see `plot title`, `set key`, `multiple keys`)
 *  A sampling range specifier for plotting with pseudofile '+' can include a
    sampling interval.  For example:
    plot sample [t=0:100:10] '+' using (t):(1):(label[t]) with labels
 *  Pseudo-file '++' generates samples on the u and v axes, rather than x and y.
    This allows placement of multiple parametric surfaces in 3D that occupy
    distinct regions of Cartesian space.  See `sampling.dem`.
 *  new formats descriptors tH tM tS handle relative times (interval lengths).
   See `time_specifiers`.
 *  ^R initiates a reverse-search through the history for the built-in readline
    which is used on Windows, too, see `command-line-editing`.
 *  Revised printing support on Windows using `set output "PRN"`,
    see `windows printing`.

*  The dot-dash pattern of a line can now be specified independent of other
    line properties. See `dashtype`, `set dashtype`, `set linetype`
 *  The default sequence of colors used for successive elements in a plot is
    more easily distinguished by users with color-vision defects.
    The color sequence is under user control (see `set colorsequence`).
    This mechanism can also be used to generate monochrome plots
    (see `set monochrome`). In previous gnuplot versions `monochrome` could only
    be selected when changing the current terminal via `set terminal`.
 *  New plot styles `with parallelaxes`, `with table`, and labeled contours.
 *  New data pre-processing filter for monotonic cubic splines (see `smooth mcsplines`)
 *  Text markup now supports bold and italic font settings in addition to
    subscript, superscript, font size and other previously available properties.
    Enhanced text mode is now enabled by default. See `enhanced text`.
    Text elements can be enclosed in a box (see `set style textbox`).
 *  Interactive terminals support hypertext labels that only appear when the
    mouse hovers over the label's anchor point.
 *  New coordinate system (Degrees, Minutes, Seconds). See `set xtics geographic`.
 *  The default format for axis labels is "% h" ("$%h$" for LaTeX terminals).
    This format is like the C standard format %g except that the exponential term,
    if present, is written using a superscript.  E.g. 1.2 x 10^5 rather than 1.2E05.
 *  Command scripts may place in-line data in a named data block for repeated
    plotting. See `inline data`.
 *  Support for 32-bit Alpha channel + RGB color #AARRGGBB.  See `colorspec`.
 *  Support for HSV color space via a translation function hsv2rgb(H,S,V).
 *  Secondary axes (x2, y2) may be locked to the primary axis via a mapping
    function.  In the simplest case this guarantees that the primary and secondary
    axis ranges are identical.  In the general case it allows you to define a
    non-linear axis, something that previously was possible only for log scaling.
    See `set link`.
 *  Each function in a plot command may optionally be preceded by a sampling
    range.  This does not affect the overall range of the plot, only the range
    over which this function is sampled.  See `plot` and `piecewise.dem`.
 *  If the external library libcerf is available, it is used to provide complex
    math routines cerf, cdawson, erfi, faddeeva, and the Voigt profile
    VP(x,sigma,gamma).
 *  The `import` command attaches a user-defined function name to a function
    provided by an external shared object (support is operating-system dependent).
    A template header and example source and make files for creating a suitable
    external shared object are provided in the demo collection.
 *  Previous commands in the history list of an interactive session can be
    reexecuted by number.  For example, `history !5` will reexecute the command
    numbered 5 in the `history` list.
 *  Bit-shift operators >> and <<.
 *  Shell invocation of gnuplot can pass parameters to a gnuplot script.
    gnuplot -c scriptfile.gp ARG1 ARG2 ARG3 ...

?changes
?differences
 Some changes introduced in version 5 may cause certain scripts written
 for earlier versions of gnuplot to behave differently.

* Revised handling of input data containing NaN, inconsistent number of data
 columns, or other unexpected content.  See Note under `missing` for examples
 and figures.

* Time coordinates are stored internally as the number of seconds relative to
 the standard unix epoch 1-Jan-1970.  Earlier versions of gnuplot used a
 different epoch internally (1-Jan-2000). This change resolves inconsistencies
 introduced whenever time in seconds was generated externally.  The epoch
 convention used by a particular gnuplot installation can be determined using
 the command `print strftime("%F",0)`.  Time is now stored to at least
 millisecond precision.

* The function `timecolumn(N,"timeformat")` now has 2 parameters. Because the
 new second parameter is not associated with any particular data axis, this
 allows using the `timecolumn` function to read time data for reasons other than
 specifying the x or y coordinate. This functionality replaces the command
 sequence `set xdata time; set timefmt "timeformat"`.  It allows combining time
 data read from multiple files with different formats within a single plot.

* The `reverse` keyword of the `set [axis]range` command affects only
 autoscaling. It does not invert or otherwise alter the meaning of a command
 such as `set xrange [0:1]`.  If you want to reverse the direction of the
 x axis in such a case, say instead `set xrange [1:0]`.

* The `call` command is provides a set of variables ARGC, ARG0, ..., ARG9.
 ARG0 holds the name of the script file being executed.  ARG1 to ARG9 are string
 variables and thus may either be referenced directly or expanded as macros,
 e.g. @ARG1.  The contents of ARG0 ... ARG9 may alternatively be accessed as
 array elements ARGV[0] ... ARGV[ARGC].  An older gnuplot convention of
 referencing call parameters as tokens $0 ... $9 is deprecated.

* The optional bandwidth for the kernel density smoothing option is taken from
 a keyword rather than a data column.  See `smooth kdensity`.

?deprecated syntax
?backwards compatibility
?compatibility
 Gnuplot version 4 deprecated certain syntax used in earlier versions but
 provided a configuration option that allowed backward compatibility.
 Support for the old syntax has now been removed.

Deprecated in version 4 and removed in version 5:
       set title "Old" 0,-1
       set data linespoints
       plot 'file' thru f(x)
       plot 1 2 4               # horizontal line at y=1
       update
 Current equivalent:
       TITLE = "New"
       set title TITLE offset char 0, char -1
       set style data linespoints
       plot 'file' using 1:(f(column(2)))
       plot 1 linetype 2 pointtype 4
       save fit "filename"
 Deprecated in version 5
       if (defined(VARNAME)) ...
       set style increment user
       call 'script' 1.23 ABC
          (in script:  print $0, "$1", "number of args = $#")
       set fontpath
       set clabel
       fit control variables FIT_*
 Current equivalent:
       if (exists("VARNAME")) ...
       set linetype
       call 'script' 1.23 "ABC"
          (in script:  print ARG1, ARG2, "number of args = ", ARGC
       set cntrlabel
       set fit <option> <value>

Deprecated in version 5.4
       # use of a file containing `reread` to perform iteration
       N = 0;  load "file-containing-reread";
       file content:
           N = N+1
           plot func(N,x)
           pause -1
           if (N<5) reread
 Current equivalent
       do for [N=1:5] {
           plot func(N, x)
           pause -1
       }

?demos
?online examples
?examples
 The `gnuplot` distribution contains a collection of examples in the `demo`
 directory. You can browse on-line versions of these examples produced by the
 png, svg, and canvas terminals at
   http://gnuplot.info/demos
 The commands that produced each demo plot are shown next to the plot, and
 the corresponding gnuplot script can be downloaded to serve as a model for
 generating similar plots.

?batch/interactive
 `Gnuplot` may be executed in either batch or interactive modes, and the two
 may even be mixed together on many systems.

Any command-line arguments are assumed to be either program options
 (see command-line-options) or names of files containing `gnuplot` commands.
 Each file or command string will be executed in the order specified.
 The special filename "-" is indicates that commands are to be read from stdin.
 `Gnuplot` exits after the last file is processed.  If no load files and no
 command strings are specified, `gnuplot` accepts interactive input from stdin.
?command-line-options
?batch/interactive command-line-options
 Gnuplot accepts the following options on the command line
      -V, --version
      -h, --help
      -p  --persist
      -d  --default-settings
      -s  --slow
      -e  "command1; command2; ..."
      -c  scriptfile ARG1 ARG2 ...

-p tells the program not to close any remaining interactive plot windows
 when the program exits.

-d tells the program not to execute any private or system initialization
 (see `initialization`).

-s tells the program to wait for slow font initialization on startup.
 Otherwise it prints an error and continues with bad font metrics.

-e "command" tells gnuplot to execute that single command before continuing.

-c is equivalent to -e "call scriptfile ARG1 ARG2 ...". See `call`.
?batch/interactive examples
 To launch an interactive session:
       gnuplot

To launch a batch session using two command files "input1" and "input2":
       gnuplot input1 input2

To launch an interactive session after an initialization file "header" and
 followed by another command file "trailer":
       gnuplot header - trailer

To give `gnuplot` commands directly in the command line, using the "-persist"
 option so that the plot remains on the screen afterwards:
       gnuplot -persist -e "set title 'Sine curve'; plot sin(x)"

To set user-defined variables a and s prior to executing commands from a file:
       gnuplot -e "a=2; s='file.png'" input.gpl
?canvas size
?canvas
?set term size

This documentation uses the term "canvas" to mean the full drawing area
 available for positioning the plot and associated elements like labels,
 titles, key, etc.  NB: For information about the HTML5 canvas terminal
 see `set term canvas`.

In earlier versions of gnuplot, some terminal types used the values from
 `set size` to control also the size of the output canvas; others did not.
 The use of 'set size' for this purpose was deprecated in version 4.
 Almost all terminals now behave as follows:

`set term <terminal_type> size <XX>, <YY>` controls the size of the output
 file, or "canvas". By default, the plot will fill this canvas.

`set size <XX>, <YY>` scales the plot itself relative to the size of the
 canvas.  Scale values less than 1 will cause the plot to not fill the entire
 canvas.  Scale values larger than 1 will cause only a portion of the plot to
 fit on the canvas.  Please be aware that setting scale values larger than 1
 may cause problems.

Example:

set size 0.5, 0.5
       set term png size 600, 400
       set output "figure.png"
       plot "data" with lines

These commands produce an output file "figure.png" that is 600 pixels
 wide and 400 pixels tall. The plot will fill the lower left quarter of this
 canvas.  This is consistent with the way multiplot mode has always worked.

?line-editing
?editing
?command-line-editing
 Command-line editing and command history are supported using either an
 external gnu readline library, an external BSD libedit library,  or a
 built-in equivalent.  This choice is a configuration option at the time
 gnuplot is built.

The editing commands of the built-in version are given below. Please note that
 the action of the DEL key is system-dependent. The gnu readline and BSD libedit
 libraries have their own documentation.

`Line-editing`:

^B    moves back a single character.
       ^F    moves forward a single character.
       ^A    moves to the beginning of the line.
       ^E    moves to the end of the line.
       ^H    deletes the previous character.
       DEL   deletes the current character.
       ^D    deletes current character, sends EOF if the line is empty.
       ^K    deletes from current position to the end of line.
       ^L    redraws line in case it gets trashed.
       ^U    deletes the entire line.
       ^W    deletes previous word.
       ^V    inhibits the interpretation of the following key as editing command.
       TAB   performs filename-completion.

`History`:

^P    moves back through history.
       ^N    moves forward through history.
       ^R    starts a backward-search.

?comments
 The comment character `#` may appear almost anywhere in a command line, and
 `gnuplot` will ignore the rest of that line. A `#` does not have this effect
 inside a quoted string. Note that if a commented line ends in '\' then the
 subsequent line is also treated as part of the comment.

See also `set datafile commentschars` for specifying a comment character for
 data files.
?coordinates
 The commands `set arrow`, `set key`, `set label` and `set object` allow you
 to draw something at an arbitrary position on the graph.  This position is
 specified by the syntax:

{<system>} <x>, {<system>} <y> {,{<system>} <z>}

Each <system> can either be `first`, `second`, `polar`, `graph`, `screen`, or
 `character`.

`first` places the x, y, or z coordinate in the system defined by the left
 and bottom axes; `second` places it in the system defined by the x2,y2 axes
 (top and right); `graph` specifies the area within the axes---0,0 is bottom
 left and 1,1 is top right (for splot, 0,0,0 is bottom left of plotting area;
 use negative z to get to the base---see `set xyplane`); `screen`
 specifies the screen area (the entire area---not just the portion selected by
 `set size`), with 0,0 at bottom left and 1,1 at top right. `character`
 coordinates are used primarily for offsets, not absolute positions.
 The `character` vertical and horizontal size depend on the current font.

`polar` causes the first two values to be interpreted as angle theta and radius
 r rather than as x and y.  This could be used, for example, to place labels on
 a 2D plot in polar coordinates or a 3D plot in cylindrical coordinates.

If the coordinate system for x is not specified, `first` is used.  If the
 system for y is not specified, the one used for x is adopted.

In some cases, the given coordinate is not an absolute position but a
 relative value (e.g., the second position in `set arrow` ... `rto`).  In
 most cases, the given value serves as difference to the first position.
 If the given coordinate belongs to a log-scaled axis, a relative value is
 interpreted as multiplier. For example,

set logscale x
       set arrow 100,5 rto 10,2

plots an arrow from position 100,5 to position 1000,7 since the x axis is
 logarithmic while the y axis is linear.

If one (or more) axis is timeseries, the appropriate coordinate should
 be given as a quoted time string according to the `timefmt` format string.
 See `set xdata` and `set timefmt`.  `Gnuplot` will also accept an integer
 expression, which will be interpreted as seconds relative to 1 January 1970.
?datastrings
 Data files may contain string data consisting of either an arbitrary string
 of printable characters containing no whitespace or an arbitrary string of
 characters, possibly including whitespace, delimited by double quotes.
 The following line from a datafile is interpreted to contain four
 columns, with a text field in column 3:

1.000 2.000 "Third column is all of this text" 4.00

Text fields can be positioned within a 2-D or 3-D plot using the commands:

plot 'datafile' using 1:2:4 with labels
   splot 'datafile' using 1:2:3:4 with labels

A column of text data can also be used to label the ticmarks along one or more
 of the plot axes. The example below plots a line through a series of points
 with (X,Y) coordinates taken from columns 3 and 4 of the input datafile.
 However, rather than generating regularly spaced tics along the x axis
 labeled numerically, gnuplot will position a tic mark along the x axis at the
 X coordinate of each point and label the tic mark with text taken from column
 1 of the input datafile.

set xtics
   plot 'datafile' using 3:4:xticlabels(1) with linespoints

There is also an option that will interpret the first entry in a column of
 input data (i.e. the column heading) as a text field, and use it as the key
 title for data plotted from that column. The example given below will use the
 first entry in column 2 to generate a title in the key box, while processing
 the remainder of columns 2 and 4 to draw the required line:

plot 'datafile' using 1:(f($2)/$4) with lines title columnhead(2)

Another example:

plot for [i=2:6] 'datafile' using i title "Results for ".columnhead(i)

This use of column headings is automated by `set datafile columnheaders` or
 `set key autotitle columnhead`.
 See `labels`, `using xticlabels`, `plot title`, `using`, `key autotitle`.
?enhanced text
?enhanced
?text_markup
?markup
?bold
?italic
 Many terminal types support an enhanced text mode in which additional
 formatting information is embedded in the text string.  For example, "x^2"
 will write x-squared as we are used to seeing it, with a superscript 2.
 This mode is selected by default when you set the terminal, but may be
 toggled afterward using "set termoption [no]enhanced", or by marking
 individual strings as in "set label 'x_2' noenhanced".

Control      Examples        Explanation
   ^           a^x             superscript
   _           a_x             subscript
   @           @x or a@^b_{cd} phantom box (occupies no width)
   &           &{space}        inserts space of specified length
   ~           ~a{.8-}         overprints '-' on 'a', raised by .8
                               times the current fontsize
   {/Times abc}                print abc in font Times at current size
   {/Times*2 abc}              print abc in font Times at twice current size
   {/Times:Italic abc}         print abc in font Times with style italic
   {/Arial:Bold=20 abc}        print abc in boldface Arial font size 20
   \U+         \U+221E         Unicode point U+221E (INFINITY)

The markup control characters act on the following single character or
 bracketed clause. The bracketed clause may contain a string of characters with
 no additional markup, e.g. 2^{10}, or it may contain additional markup that
 changes font properties.  Font specifiers MUST be preceded by a '/' character
 that immediately follows the opening '{'.  If a font name contains spaces it
 must be enclosed in single or double quotes.

Examples: The first example illustrates nesting one bracketed clause inside
 another to produce a boldface A with an italic subscript i, all in the current
 font.  If the clause introduced by :Normal were omitted the subscript would be
 both italic and boldface.  The second example illustrates the same markup
 applied to font "Times New Roman" at 20 point size.
      {/:Bold A_{/:Normal{/:Italic i}}}
      {/"Times New Roman":Bold=20 A_{/:Normal{/:Italic i}}}

The phantom box is useful for a@^b_c to align superscripts and subscripts
 but does not work well for overwriting an accent on a letter.  For the latter,
 it is much better to use an encoding  (e.g. iso_8859_1 or utf8) that contains
 a large variety of letters with accents or other diacritical marks.  See
 `set encoding`. Since the box is non-spacing, it is sensible to put the shorter
 of the subscript or superscript in the box (that is, after the @).

Space equal in length to a string can be inserted using the '&' character.
 Thus
         'abc&{def}ghi'
 would produce
         'abc   ghi'.

The '~' character causes the next character or bracketed text to be
 overprinted by the following character or bracketed text.  The second text
 will be horizontally centered on the first.  Thus '~a/' will result in an 'a'
 with a slash through it.  You can also shift the second text vertically by
 preceding the second text with a number, which will define the fraction of the
 current fontsize by which the text will be raised or lowered.  In this case
 the number and text must be enclosed in brackets because more than one
 character is necessary.  If the overprinted text begins with a number, put a
 space between the vertical offset and the text ('~{abc}{.5 000}'); otherwise
 no space is needed ('~{abc}{.5---}').  You can change the font for one or
 both strings ('~a{.5 /*.2 o}'---an 'a' with a one-fifth-size 'o' on top---and
 the space between the number and the slash is necessary), but you can't
 change it after the beginning of the string.  Neither can you use any other
 special syntax within either string.  You can, of course, use control
 characters by escaping them (see below), such as '~a{\^}'

You can escape control characters using \, e.g.,  \\, \{, and so on.
 See `escape sequences` below.

Note that strings in double-quotes are parsed differently than those enclosed
 in single-quotes.  The major difference is that backslashes may need to be
 doubled when in double-quoted strings.

The file "ps_guide.ps" in the /docs/psdoc subdirectory of the gnuplot source
 distribution contains more examples of the enhanced syntax, as does the demo
 `enhanced_utf8.dem`

?escape sequences
?enhanced text escape sequences
?unicode
 The backslash character \ is used to escape single byte character codes or
 Unicode entry points.

The form \ooo (where ooo is a 3 character octal value) can be used to index a
 known character code in a specific font encoding.  For example the Adobe Symbol
 font uses a custom encoding in which octal 245 represents the infinity symbol.
 You could embed this in an enhanced text string by giving the font name and the
 character code "{/Symbol \245}".  This is mostly useful for the PostScript
 terminal, which cannot easily handle UTF-8 encoding.

You can specify a character by its Unicode code point as \U+hhhh, where hhhh
 is the 4 or 5 character hexadecimal code point. For example the code point for
 the infinity symbol is \U+221E.  This will be converted to a UTF-8 byte
 sequence on output if appropriate.  In a UTF-8 environment this mechanism
 is not needed for printable special characters since they are handled in a
 text string like any other character. However it is useful for combining forms
 or supplemental diacritical marks (e.g. an arrow over a letter to represent
 a vector).  See `set encoding`, `utf8`, and the
 online unicode demo.

?environment
 A number of shell environment variables are understood by `gnuplot`.  None of
 these are required, but may be useful.

GNUTERM, if defined, is used to set the terminal type on start-up.
 Starting with version 5.2 the entire string in GNUTERM is passed to
 "set term" so that terminal options may be included.  E.g.
      GNUTERM="postscript eps color size 5in, 3in"
 This can be overridden by the ~/.gnuplot (or equivalent) start-up file
 (see `startup`) and of course by later explicit `set term` commands.

GNUHELP may be defined to be the pathname of the HELP file (gnuplot.gih).

On VMS, the logical name GNUPLOT$HELP should be defined as the name of the
 help library for `gnuplot`.  The `gnuplot` help can be put inside any VMS
 system help library.

On Unix, HOME is used as the name of a directory to search for a .gnuplot
 file if none is found in the current directory.  On MS-DOS, Windows and OS/2,
 GNUPLOT is used.  On Windows, the NT-specific variable USERPROFILE is also
 tried. VMS, SYS$LOGIN: is used. Type `help startup`.

On Unix, PAGER is used as an output filter for help messages.

On Unix, SHELL is used for the `shell` command.  On MS-DOS and OS/2, COMSPEC
 is used for the `shell` command.

`FIT_SCRIPT` may be used to specify a `gnuplot` command to be executed when a
 fit is interrupted---see `fit`.  `FIT_LOG` specifies the default filename of the
 logfile maintained by fit.

GNUPLOT_LIB may be used to define additional search directories for data
 and command files. The variable may contain a single directory name, or
 a list of directories separated by a platform-specific path separator,
 eg. ':' on Unix, or ';' on DOS/Windows/OS/2 platforms. The contents
 of GNUPLOT_LIB are appended to the `loadpath` variable, but not saved
 with the `save` and `save set` commands.

Several gnuplot terminal drivers access TrueType fonts via the gd library.
 For these drivers the font search path is controlled by the environmental
 variable GDFONTPATH.  Furthermore, a default font for these drivers may be
 set via the environmental variable GNUPLOT_DEFAULT_GDFONT.

The postscript terminal uses its own font search path. It is controlled by
 the environmental variable GNUPLOT_FONTPATH.

GNUPLOT_PS_DIR is used by the postscript driver to search for external
 prologue files. Depending on the build process, gnuplot contains either a
 built-in copy of those files or a default hardcoded path. You can use this
 variable have the postscript terminal use custom prologue files rather than
 the default files. See `postscript prologue`.
?expressions
?division
 In general, any mathematical expression accepted by C, FORTRAN, Pascal, or
 BASIC is valid.  The precedence of these operators is determined by the
 specifications of the C programming language.  White space (spaces and tabs)
 is ignored inside expressions.

Note that gnuplot uses both "real" and "integer" arithmetic, like FORTRAN and
 C.  Integers are entered as "1", "-10", etc; reals as "1.0", "-10.0", "1e1",
 3.5e-1, etc.  The most important difference between the two forms is in
 division: division of integers truncates: 5/2 = 2; division of reals does
 not: 5.0/2.0 = 2.5.  In mixed expressions, integers are "promoted" to reals
 before evaluation: 5/2e0 = 2.5.  The result of division of a negative integer
 by a positive one may vary among compilers.  Try a test like "print -5/2" to
 determine if your system always rounds down (-5/2 yields -3) or always rounds
 toward zero (-5/2 yields -2).

The integer expression "1/0" may be used to generate an "undefined" flag,
 which causes a point to be ignored.  Or you can use the pre-defined variable
 NaN to achieve the same result.  See `using` for an example.

Gnuplot can also perform simple operations on strings and string variables.
 For example, the expression ("A" . "B" eq "AB") evaluates as true, illustrating
 the string concatenation operator and the string equality operator.

A string which contains a numerical value is promoted to the corresponding
 integer or real value if used in a numerical expression. Thus ("3" + "4" == 7)
 and (6.78 == "6.78") both evaluate to true.  An integer, but not a real or
 complex value, is promoted to a string if used in string concatenation.
 A typical case is the use of integers to construct file names or other strings;
 e.g. ("file" . 4 eq "file4") is true.

Substrings can be specified using a postfixed range descriptor [beg:end].
 For example, "ABCDEF"[3:4] == "CD"   and   "ABCDEF"[4:*] == "DEF"
 The syntax "string"[beg:end] is exactly equivalent to calling the built-in
 string-valued function substr("string",beg,end), except that you cannot
 omit either beg or end from the function call.
?complex arithmetic
?complex
 Arithmetic operations and most built-in functions support the use of complex
 arguments.  Complex constants are expressed as {<real>,<imag>}, where <real>
 and <imag> must be numerical constants.  Thus {0,1} represents 'i'.
 The real and imaginary components of complex value x can be extracted as
 real(x) and imag(x). The modulus is given by abs(x).

Gnuplot's standard 2D and 3D plot styles can plot only real values; if you
 need to plot a complex-valued function f(x) with non-zero imaginary components
 you must choose between plotting real(f(x)) or abs(f(x)).  For examples of
 representing complex values using color, see the
 complex trigonometric function demos (complex_trig.dem)

?constants
?expressions constants
?octal
?hexadecimal
?complex constants
 Integer constants are interpreted via the C library routine strtoll().
 This means that constants beginning with "0" are interpreted as octal,
 and constants beginning with "0x" or "0X" are interpreted as hexadecimal.

Floating point constants are interpreted via the C library routine atof().

Complex constants are expressed as {<real>,<imag>}, where <real> and <imag>
 must be numerical constants.  For example, {3,2} represents 3 + 2i; {0,1}
 represents 'i' itself.  The curly braces are explicitly required here.

String constants consist of any sequence of characters enclosed either in
 single quotes or double quotes. The distinction between single and double
 quotes is important.  See `quotes`.

Examples:
      1 -10 0xffaabb        # integer constants
      1.0 -10. 1e1 3.5e-1   # floating point constants
      {1.2, -3.4}           # complex constant
      "Line 1\nLine 2"      # string constant (\n is expanded to newline)
      '123\n456'            # string constant (\ and n are ordinary characters)

?expressions functions
 Arguments to math functions in `gnuplot` can be integer, real, or complex
 unless otherwise noted.  Functions that accept or return angles (e.g. sin(x))
 treat angle values as radians, but this may be changed to degrees using the
 command `set angles`.

?expressions functions abs
?abs
 The `abs(x)` function returns the absolute value of its argument.  The
 returned value is of the same type as the argument.

For complex arguments, abs(x) is defined as the length of x in the complex
 plane [i.e.,  sqrt(real(x)**2 + imag(x)**2) ]. This is also known as the norm
 or complex modulus of x.
?expressions functions acos
?acos
 The `acos(x)` function returns the arc cosine (inverse cosine) of its
 argument.  `acos` returns its argument in radians or degrees, as selected by
 `set angles`.
?expressions functions acosh
?acosh
 The `acosh(x)` function returns the inverse hyperbolic cosine of its argument
 in radians.
?expressions functions airy
?airy
 The `airy(x)` function returns the value of the Airy function Ai(x) of its
 argument. The function Ai(x) is that solution of the equation y'' - x y = 0
 which is everywhere finite. If the argument is complex, its imaginary part
 is ignored.
?expressions functions arg
?arg
 The `arg(x)` function returns the phase of a complex number in radians or
 degrees, as selected by `set angles`.
?expressions functions asin
?asin
 The `asin(x)` function returns the arc sin (inverse sin) of its argument.
 `asin` returns its argument in radians or degrees, as selected by `set
 angles`.
?expressions functions asinh
?asinh
 The `asinh(x)` function returns the inverse hyperbolic sin of its argument in
 radians.
?expressions functions atan
?atan
 The `atan(x)` function returns the arc tangent (inverse tangent) of its
 argument.  `atan` returns its argument in radians or degrees, as selected by
 `set angles`.
?expressions functions atan2
?atan2
 The `atan2(y,x)` function returns the arc tangent (inverse tangent) of the
 ratio of the real parts of its arguments.  `atan2` returns its argument in
 radians or degrees, as selected by `set angles`, in the correct quadrant.
?expressions functions atanh
?atanh
 The `atanh(x)` function returns the inverse hyperbolic tangent of its
 argument in radians.
?expressions functions EllipticK
?EllipticK
 The `EllipticK(k)` function returns the complete elliptic integral of the
 first kind. See `elliptic integrals` for more details.
?expressions functions EllipticE
?EllipticE
 The `EllipticE(k)` function returns the complete elliptic integral of the
 second kind. See `elliptic integrals` for more details.
?expressions functions EllipticPi
?EllipticPi
 The `EllipticPi(n,k)` function returns the complete elliptic integral of the
 third kind. See `elliptic integrals` for more details.
?expressions functions besj0
?besj0
 The `besj0(x)` function returns the J0th Bessel function of its argument.
 `besj0` expects its argument to be in radians.
?expressions functions besj1
?besj1
 The `besj1(x)` function returns the J1st Bessel function of its argument.
 `besj1` expects its argument to be in radians.
?expressions functions besjn
?besjn
 The `besjn(n,x)` functions returns the Jn Bessel function of x in radians.
?expressions functions besy0
?besy0
 The `besy0(x)` function returns the Y0th Bessel function of its argument.
 `besy0` expects its argument to be in radians.
?expressions functions besy1
?besy1
 The `besy1(x)` function returns the Y1st Bessel function of its argument.
 `besy1` expects its argument to be in radians.
?expressions functions besyn
?besyn
 The `besyn(n,x)` functions returns the Yn Bessel function of x in radians.
?expressions functions besi0
?besi0
 The `besi0(x)` function is the modified Bessel function or order 0.
 `besi0` expects its argument to be in radians.
?expressions functions besi1
?besi1
 The `besi1(x)` function is the modified Bessel function or order 1.
 `besi1` expects its argument to be in radians.
?expressions functions besin
?besin
 `besin(n,x)` is the modified Bessel function or order n for integer n and
 x in radians.
?expressions functions ceil
?ceil
 The `ceil(x)` function returns the smallest integer that is not less than its
 argument.  For complex numbers, `ceil` returns the smallest integer not less
 than the real part of its argument.
?expressions functions cos
?cos
 The `cos(x)` function returns the cosine of its argument.  `cos` accepts its
 argument in radians or degrees, as selected by `set angles`.
?expressions functions cosh
?cosh
 The `cosh(x)` function returns the hyperbolic cosine of its argument.  `cosh`
 expects its argument to be in radians.
?expressions functions erf
?erf
 The `erf(x)` function returns the error function of the real part of its
 argument.  If the argument is a complex value, the imaginary component is
 ignored.  See `erfc`, `inverf`, and `norm`.
?expressions functions erfc
?erfc
 The `erfc(x)` function returns 1.0 - the error function of the real part of
 its argument.  If the argument is a complex value, the imaginary component is
 ignored.  See `erf`, `inverf`, and `norm`.
?expressions functions exp
?exp
 The `exp(x)` function returns `e` raised to the power of x, which can be
 an integer, real, or complex value.
?expressions functions expint
?expint
 The `expint(n,x)` function returns the exponential integral of the real
 part of its argument: integral from 1 to infinity of t^(-n) e^(-tx) dt.
 n must be a nonnegative integer, x>=0, and either x>0 or n>1.
?expressions functions floor
?floor
 The `floor(x)` function returns the largest integer not greater than its
 argument.  For complex numbers, `floor` returns the largest integer not
 greater than the real part of its argument.
?expressions functions gamma
?gamma
 The `gamma(x)` function returns the gamma function of the real part of its
 argument.  For integer n, gamma(n+1) = n!.  If the argument is a complex
 value, the imaginary component is ignored.
?expressions functions ibeta
?ibeta
 The `ibeta(p,q,x)` function returns the incomplete beta function of the real
 parts of its arguments. p, q > 0 and x in [0:1].  If the arguments are
 complex, the imaginary components are ignored.  The function is approximated by
 the method of continued fractions (Abramowitz and Stegun, 1964).
 The approximation is only accurate in the region x < (p-1)/(p+q-2).
?expressions functions inverf
?inverf
 The `inverf(x)` function returns the inverse error function of the real part
 of its argument.   See `erf` and `invnorm`.
?expressions functions igamma
?igamma
 The `igamma(a,x)` function returns the normalized incomplete gamma
 function of the real parts of its arguments, where a > 0 and x >= 0.
 The standard notation is P(a,x), e.g. Abramowitz and Stegun (6.5.1),
 with limiting value of 1 as x approaches infinity.  If the arguments
 are complex, the imaginary components are ignored.
?expressions functions imag
?imag
 The `imag(x)` function returns the imaginary part of its argument as a real
 number.
?expressions functions invnorm
?invnorm
 The `invnorm(x)` function returns the inverse cumulative normal (Gaussian)
 distribution function of the real part of its argument.  See `norm`.
?expressions functions int
?int
 The `int(x)` function returns the integer part of its argument, truncated
 toward zero.
?expressions functions lambertw
?lambertw
 The `lambertw(x)` function returns the value of the principal branch of
 Lambert's W function, which is defined by the equation (W(x)*exp(W(x))=x.
 x must be a real number with x >= -exp(-1).
?expressions functions lgamma
?lgamma
 The `lgamma(x)` function returns the natural logarithm of the gamma function
 of the real part of its argument.  If the argument is a complex value, the
 imaginary component is ignored.
?expressions functions log
?log
 The `log(x)` function returns the natural logarithm (base `e`) of its
 argument.  See `log10`.
?expressions functions log10
?log10
 The `log10(x)` function returns the logarithm (base 10) of its argument.
?expressions functions norm
?norm
 The `norm(x)` function returns the cumulative normal (Gaussian) distribution
 function of the real part of its argument.   See `invnorm`, `erf` and `erfc`.
?expressions functions rand
?rand
 The `rand(x)` function returns a pseudo random number in the interval (0:1).
 See `random` for more details.
?expressions functions real
?real
 The `real(x)` function returns the real part of its argument.
?expressions functions sgn
?sgn
 The `sgn(x)` function returns 1 if its argument is positive, -1 if its
 argument is negative, and 0 if its argument is 0.  If the argument is a
 complex value, the imaginary component is ignored.
?expressions functions sin
?sin
 The `sin(x)` function returns the sine of its argument.  `sin` expects its
 argument to be in radians or degrees, as selected by `set angles`.
?expressions functions sinh
?sinh
 The `sinh(x)` function returns the hyperbolic sine of its argument.  `sinh`
 expects its argument to be in radians.
?expressions functions sqrt
?sqrt
 The `sqrt(x)` function returns the square root of its argument. If the
 x is a complex value, this always returns the root with positive real
 part.
?expressions functions tan
?tan
 The `tan(x)` function returns the tangent of its argument.  `tan` expects
 its argument to be in radians or degrees, as selected by `set angles`.
?expressions functions tanh
?tanh
 The `tanh(x)` function returns the hyperbolic tangent of its argument.  `tanh`
 expects its argument to be in radians.
?expressions functions voigt
?voigt
 The function `voigt(x,y)` returns an approximation to the Voigt/Faddeeva
 function used in spectral analysis. The approximation is accurate to
 one part in 10^4.  If the libcerf routines are available, the re_w_of_z()
 routine is used to provide a more accurate value.
 Note that voigt(x,y) = real(faddeeva( x + y*{0,1} )).

?expressions functions cerf
?cerf
 `cerf(z)` is the complex version of the error function erf(x)
?expressions functions cdawson
?cdawson
 `cdawson(z)` returns Dawson's Integral evaluated for the complex argument z.
 cdawson(z) = sqrt(pi)/2 * exp(-z^2) * erfi(z)
?expressions functions faddeeva
?faddeeva
 The `faddeeva(z)` function returns the rescaled complex error function
 faddeeva(z) = exp(-z^2) * erfc(-i*z)
 This corresponds to Eqs 7.1.3 and 7.1.4 of Abramowitz and Stegun.
?expressions functions erfi
?erfi
 Imaginary error function erfi(x) = -i * erf(ix)
?expressions functions VP
?VP
 `VP(x,sigma,gamma)` corresponds to the Voigt profile defined by convolution of
 a Gaussian G(x;sigma) with a Lorentzian L(x;gamma).

?expressions functions gprintf
 `gprintf("format",x)` applies gnuplot's own format specifiers to the single
 variable x and returns the resulting string. If you want standard C-language
 format specifiers, you must instead use `sprintf("format",x)`.
 See `format specifiers`.
?expressions functions sprintf
?sprintf
 `sprintf("format",var1,var2,...)` applies standard C-language format specifiers
 to multiple arguments and returns the resulting string. If you want to
 use gnuplot's own format specifiers, you must instead call `gprintf()`.
 For information on sprintf format specifiers, please see standard C-language
 documentation or the unix sprintf man page.
?expressions functions strlen
?strlen
 `strlen("string")` returns the number of characters in a string taking into
 account the current encoding.  If the current encoding supports multibyte
 characters (SJIS UTF8), this may be less than the number of bytes in the string.
 If the string contains multibyte UTF8 characters but the current encoding is
 set to something other than UTF8, strlen("utf8string") will return a value that
 is larger than the actual number of characters.
?expressions functions strstrt
?strstrt
 `strstrt("string","key")` searches for the character string "key" in "string"
 and returns the index to the first character of "key". If "key" is not found,
 it returns 0. Similar to C library function strstr except that it returns an
 index rather than a string pointer. strstrt("hayneedlestack","needle") = 4.
 This function is aware of utf8 encoding, so strstrt("αβγ","β") returns 2.
?expressions functions substr
?substr
 `substr("string",beg,end)` returns the substring consisting of characters
 beg through end of the original string. This is exactly equivalent to the
 expression "string"[beg:end] except that you do not have the option of
 omitting beg or end.
?expressions functions strftime
?strftime
 `strftime("timeformat",t)` applies the timeformat specifiers to the time t
 given in seconds since the year 1970.
 See `time_specifiers` and `strptime`.
?expressions functions strptime
?strptime
 `strptime("timeformat",s)` reads the time from the string s using the
 timeformat specifiers and converts it into seconds since the year 1970.
 See `time_specifiers` and `strftime`.
?expressions functions system
 `system("command")` executes "command" using the standard shell and returns
 the resulting character stream from stdout as string variable.
 One optional trailing newline is ignored.

This can be used to import external functions into gnuplot scripts using
 'f(x) = real(system(sprintf("somecommand %f", x)))'.
 `trim("  padded string ")` returns the original string stripped of leading
 and trailing whitespace.  This is useful for string comparisons of input
 data fields that may contain extra whitespace. For example
      plot FOO using 1:( trim(strcol(3)) eq "A" ? $2 : NaN )
 `word("string",n)` returns the nth word in string. For example,
 `word("one two three",2)` returns the string "two".
 `words("string")` returns the number of words in string. For example,
 `words(" a b c d")` returns 4.

?expressions functions column
?column
 `column(x)` may be used only as part of a plot, splot, or stats command.
 It evaluates to the numerical value of the content of column x.
 See `plot datafile using`.
?expressions functions columnhead
?columnhead
 `columnhead(x)` may only be used as part of a plot, splot, or stats command.
 It evaluates to a string containing the content of column x in the first line
 of a data file. See `plot datafile using`.
?expressions functions exists
?exists
 The argument to `exists()` is a string constant or a string variable;
 if the string contains the name of a defined variable, the function returns 1.
 Otherwise the function returns 0.
?expressions functions hsv2rgb
?hsv2rgb
?hsv
 The `hsv2rgb(h,s,v)` function converts HSV (Hue/Saturation/Value) triplet
 to an equivalent RGB value.
?expressions functions palette
?palette
 `palette(z)` returns the RGB representation of the palette color mapped to z
  given the current extremes of cbrange.
?expressions functions stringcolumn
?stringcolumn
?expressions functions strcol
?strcol
 `stringcolumn(x)` may be used only in expressions as part of `using` manipulations
 to fits or datafile plots.  It returns the content of column x as a string variable.
 `strcol(x)` is shorthand for `stringcolumn(x)`.
 See `plot datafile using`.
?expressions functions timecolumn
?timecolumn
 `timecolumn(N,"timeformat")` may be used only in expressions as part of `using`
 manipulations to fits or datafile plots.   See `plot datafile using`.

It reads string data starting at column N as a time/date value and uses "timeformat"
 to interpret this as "seconds since the epoch" to millisecond precision.
 If no format parameter is given, the format defaults to the string from 
 `set timefmt`.
?expressions functions tm_hour
?tm_hour
 The `tm_hour(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the hour (an integer in the range 0--23) as a real.
?expressions functions tm_mday
?tm_mday
 The `tm_mday(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the day of the month (an integer in the range 1--31)
 as a real.
?expressions functions tm_min
?tm_min
 The `tm_min(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the minute (an integer in the range 0--59) as a real.
?expressions functions tm_mon
?tm_mon
 The `tm_mon(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the month (an integer in the range 0--11) as a real.
?expressions functions tm_sec
?tm_sec
 The `tm_sec(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the second (an integer in the range 0--59) as a real.
?expressions functions tm_wday
?tm_wday
 The `tm_wday(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the day of the week (Sun..Sat) as an integer (0..6).
?expressions functions tm_yday
?tm_yday
 The `tm_yday(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the day of the year (an integer in the range 0--365)
 as a real.
?expressions functions tm_year
?tm_year
 The `tm_year(t)` function interprets its argument as a time, in seconds from
 1 Jan 1970.  It returns the year (an integer) as a real.
?expressions functions time
?time
?epoch
 The `time(x)` function returns the current system time. This value can be
 converted to a date string with the `strftime` function, or it can be used
 in conjunction with `timecolumn` to generate relative time/date plots.
 The type of the argument determines what is returned. If the argument is an
 integer, time() returns the current time as an integer, in seconds from
 the epoch start, 1 Jan 1970.  If the argument is real the result is also
 real and may include fractional seconds.  If the argument is a string,
 it is assumed to be a format and  is passed to `strftime` to provide a
 formatted time string.  See also `time_specifiers` and `timefmt`.
?expressions functions valid
?valid
 `valid(x)` may be used only in expressions as part of `using` manipulations
 to fits or datafile plots.  See `plot datafile using`.

?expressions functions voxel
?voxel
 The function voxel(x,y,z) returns the value of the voxel in the currently
 active grid that contains the point (x,y,z).  It may also be used on the
 left side of an assignment statement to set the value of that voxel.
 E.g. voxel(x,y,z) = 0.0
 See `splot voxel-grids`, `vgrid`.
?elliptic integrals
 The `EllipticK(k)` function returns the complete elliptic integral of the first
 kind, i.e. the definite integral between 0 and pi/2 of the function
 `(1-(k*sin(p))**2)**(-0.5)`.  The domain of `k` is -1 to 1 (exclusive).

The `EllipticE(k)` function returns the complete elliptic integral of the
 second kind, i.e. the definite integral between 0 and pi/2 of the function
 `(1-(k*sin(p))**2)**0.5`.  The domain of `k` is -1 to 1 (inclusive).

The `EllipticPi(n,k)` function returns the complete elliptic integral of the
 third kind, i.e. the definite integral between 0 and pi/2 of the function
 `(1-(k*sin(p))**2)**(-0.5)/(1-n*sin(p)**2)`.  The parameter `n` must be less
 than 1, while `k` must lie between -1 and 1 (exclusive).  Note that by
 definition EllipticPi(0,k) == EllipticK(k) for all possible values of `k`.
?expressions random
?random
 The function `rand()` produces a sequence of pseudo-random numbers between
 0 and 1 using an algorithm from P. L'Ecuyer and S. Cote, "Implementing a
 random number package with splitting facilities", ACM Transactions on
 Mathematical Software, 17:98-111 (1991).

rand(0)     returns a pseudo random number in the open interval (0:1)
                   generated from the current value of two internal
                   32-bit seeds.
       rand(-1)    resets both seeds to a standard value.
       rand(x)     for integer 0 < x < 2^31-1 sets both internal seeds
                   to x.
       rand({x,y}) for integer 0 < x,y < 2^31-1 sets seed1 to x and
                   seed2 to y.
?expressions functions value
?value
 B = value("A") is effectively the same as B = A, where A is the name of a
 user-defined variable.  This is useful when the name of the variable is itself
 held in a string variable. See `user-defined variables`.  It also allows you to
 read the name of a variable from a data file.  If the argument is a numerical
 expression, value() returns the value of that expression.  If the argument is a
 string that does not correspond to a currently defined variable,
 value() returns NaN.

?expressions functions word
?expressions functions words
?words
?word
 `word("string",n)` returns the nth word in string. For example,
 `word("one two three",2)` returns the string "two".

`words("string")` returns the number of words in string. For example,
 `words(" a b c d")` returns 4.

The `word` and `words` functions provide limited support for quoted strings,
 both single and double quotes can be used:
       print words("\"double quotes\" or 'single quotes'")   # 3
 A starting quote must either be preceded by a white space, or start the
 string. This means that apostrophes in the middle or at the end of words are
 considered as parts of the respective word:
       print words("Alexis' phone doesn't work") # 4
 Escaping quote characters is not supported. If you want to keep certain quotes,
 the respective section must be surrounded by the other kind of quotes:
       s = "Keep \"'single quotes'\" or '\"double quotes\"'"
       print word(s, 2) # 'single quotes'
       print word(s, 4) # "double quotes"
 Note, that in this last example the escaped quotes are necessary only for the
 string definition.

?expressions functions trim
?trim
 `trim("  padded string ")` returns the original string stripped of leading
 and trailing whitespace.  This is useful for string comparisons of input
 data fields that may contain extra whitespace. For example
      plot FOO using 1:( trim(strcol(3)) eq "A" ? $2 : NaN )

?expressions operators
?operators
 The operators in `gnuplot` are the same as the corresponding operators in the
 C programming language, except that all operators accept integer, real, and
 complex arguments, unless otherwise noted.  The ** operator (exponentiation)
 is supported, as in FORTRAN.

Parentheses may be used to change order of evaluation.
?expressions operators unary
?operators unary
?unary
 The following is a list of all the unary operators and their usages:

Symbol      Example    Explanation
       -           -a          unary minus
       +           +a          unary plus (no-operation)
       ~           ~a        * one's complement
       !           !a        * logical negation
       !           a!        * factorial
       $           $3        * call arg/column during `using` manipulation
       ||          |A|         cardinality of array A

(*) Starred explanations indicate that the operator requires an integer
 argument.

Operator precedence is the same as in Fortran and C.  As in those languages,
 parentheses may be used to change the order of operation.  Thus -2**2 = -4,
 but (-2)**2 = 4.

The factorial operator returns an integer when N! is sufficiently small
 (N <= 20 for 64-bit integers). It returns a floating point approximation
 for larger values of N.

?cardinality
 This operator returns the number of elements |A| when applied to array A.
 It returns the number of data lines |$DATA| when applied to datablock $DATA.
?expressions operators binary
?operators binary
 The following is a list of all the binary operators and their usages:

Symbol       Example      Explanation
       **          a**b          exponentiation
       *           a*b           multiplication
       /           a/b           division
       %           a%b         * modulo
       +           a+b           addition
       -           a-b           subtraction
       ==          a==b          equality
       !=          a!=b          inequality
       <           a<b           less than
       <=          a<=b          less than or equal to
       >           a>b           greater than
       >=          a>=b          greater than or equal to
       <<          0xff<<1       left shift unsigned
       >>          0xff>>2       right shift unsigned
       &           a&b         * bitwise AND
       ^           a^b         * bitwise exclusive OR
       |           a|b         * bitwise inclusive OR
       &&          a&&b        * logical AND
       ||          a||b        * logical OR
       =           a = b         assignment
       ,           (a,b)         serial evaluation
       .           A.B           string concatenation
       eq          A eq B        string equality
       ne          A ne B        string inequality

(*) Starred explanations indicate that the operator requires integer
 arguments.
 Capital letters A and B indicate that the operator requires string arguments.

Logical AND (&&) and OR (||) short-circuit the way they do in C.  That is,
 the second `&&` operand is not evaluated if the first is false; the second
 `||` operand is not evaluated if the first is true.

Serial evaluation occurs only in parentheses and is guaranteed to proceed
 in left to right order.  The value of the rightmost subexpression is returned.
?expressions operators ternary
?operators ternary
?ternary
 There is a single ternary operator:

Symbol       Example      Explanation
       ?:          a?b:c     ternary operation

The ternary operator behaves as it does in C.  The first argument (a), which
 must be an integer, is evaluated.  If it is true (non-zero), the second
 argument (b) is evaluated and returned; otherwise the third argument (c) is
 evaluated and returned.

The ternary operator is very useful both in constructing piecewise functions
 and in plotting points only when certain conditions are met.

Examples:

Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <= x < 2,
 and undefined elsewhere:
       f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
       plot f(x)
 Note that `gnuplot` quietly ignores undefined values, so the final branch of
 the function (1/0) will produce no plottable points.  Note also that f(x)
 will be plotted as a continuous function across the discontinuity if a line
 style is used.  To plot it discontinuously, create separate functions for the
 two pieces.  (Parametric functions are also useful for this purpose.)

For data in a file, plot the average of the data in columns 2 and 3 against
 the datum in column 1, but only if the datum in column 4 is non-negative:

plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )

For an explanation of the `using` syntax, please see `plot datafile using`.
?expressions operators summation
?operators summation
?summation
 A summation expression has the form
       sum [<var> = <start> : <end>] <expression>
 <var> is treated as an integer variable that takes on successive integral
 values from <start> to <end>.  For each of these, the current value of
 <expression> is added to a running total whose final value becomes the value
 of the summation expression.
 Examples:
       print sum [i=1:10] i
           55.
       # Equivalent to plot 'data' using 1:($2+$3+$4+$5+$6+...)
       plot 'data' using 1 : (sum [col=2:MAXCOL] column(col))
 It is not necessary that <expression> contain the variable <var>.
 Although <start> and <end> can be specified as variables or expressions,
 their value cannot be changed dynamically as a side-effect of carrying
 out the summation. If <end> is less than <start> then the value of the
 summation is zero.
?expressions gnuplot-defined
?gnuplot-defined
?gnuplot-defined variables
?GPVAL
?gpval
 Gnuplot maintains a number of read-only variables that reflect the current
 internal state of the program and the most recent plot. These variables begin
 with the prefix "GPVAL_".
 Examples include GPVAL_TERM, GPVAL_X_MIN, GPVAL_X_MAX, GPVAL_Y_MIN.
 Type `show variables all` to display the complete list and current values.
 Values related to axes parameters (ranges, log base) are values used during the
 last plot, not those currently `set`.

Example:  To calculate the fractional screen coordinates of the point [X,Y]
      GRAPH_X = (X - GPVAL_X_MIN) / (GPVAL_X_MAX - GPVAL_X_MIN)
      GRAPH_Y = (Y - GPVAL_Y_MIN) / (GPVAL_Y_MAX - GPVAL_Y_MIN)
      SCREEN_X = GPVAL_TERM_XMIN + GRAPH_X * (GPVAL_TERM_XMAX - GPVAL_TERM_XMIN)
      SCREEN_Y = GPVAL_TERM_YMIN + GRAPH_Y * (GPVAL_TERM_YMAX - GPVAL_TERM_YMIN)
      FRAC_X = SCREEN_X * GPVAL_TERM_SCALE / GPVAL_TERM_XSIZE
      FRAC_Y = SCREEN_Y * GPVAL_TERM_SCALE / GPVAL_TERM_YSIZE

The read-only variable GPVAL_ERRNO is set to a non-zero value if any gnuplot
 command terminates early due to an error.  The most recent error message is
 stored in the string variable GPVAL_ERRMSG.  Both GPVAL_ERRNO and GPVAL_ERRMSG
 can be cleared using the command `reset errors`.

Interactive terminals with `mouse` functionality maintain read-only variables
 with the prefix "MOUSE_".  See `mouse variables` for details.

The `fit` mechanism uses several variables with names that begin "FIT_".  It
 is safest to avoid using such names.  When using `set fit errorvariables`, the
 error for each fitted parameter will be stored in a variable named like the
 parameter, but with "_err" appended.  See the documentation on `fit` and
 `set fit` for details.

See `user-defined variables`, `reset errors`, `mouse variables`, and `fit`.

?expressions user-defined
?user-defined variables
?user-defined
?variables
 New user-defined variables and functions of one through twelve variables may
 be declared and used anywhere, including on the `plot` command itself.

User-defined function syntax:
       <func-name>( <dummy1> {,<dummy2>} ... {,<dummy12>} ) = <expression>

where <expression> is defined in terms of <dummy1> through <dummy12>.

User-defined variable syntax:
       <variable-name> = <constant-expression>

Examples:
       w = 2
       q = floor(tan(pi/2 - 0.1))
       f(x) = sin(w*x)
       sinc(x) = sin(pi*x)/(pi*x)
       delta(t) = (t == 0)
       ramp(t) = (t > 0) ? t : 0
       min(a,b) = (a < b) ? a : b
       comb(n,k) = n!/(k!*(n-k)!)
       len3d(x,y,z) = sqrt(x*x+y*y+z*z)
       plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)

file = "mydata.inp"
       file(n) = sprintf("run_%d.dat",n)

The final two examples illustrate a user-defined string variable and a
 user-defined string function.

Note that the variables `pi` (3.14159...) and `NaN` (IEEE "Not a Number") are
 already defined.  You can redefine these to something else if you really need
 to. The original values can be recovered by setting:

NaN = GPVAL_NaN
       pi  = GPVAL_pi

Other variables may be defined under various gnuplot operations like mousing in
 interactive terminals or fitting; see `gnuplot-defined variables` for details.

You can check for existence of a given variable V by the exists("V")
 expression. For example
       a = 10
       if (exists("a")) print "a is defined"
       if (!exists("b")) print "b is not defined"

Valid names are the same as in most programming languages: they must begin
 with a letter, but subsequent characters may be letters, digits, or "_".

Each function definition is made available as a special string-valued
 variable with the prefix 'GPFUN_'.

Example:
       set label GPFUN_sinc at graph .05,.95

See `show functions`, `functions`, `gnuplot-defined variables`, `macros`,
 `value`.
?arrays
 Arrays are implemented as indexed lists of user variables.  The elements in an
 array are not limited to a single type of variable.  Arrays must be created
 explicitly before being referenced. The size of an array cannot be changed
 after creation.  All elements are initially undefined.  In most places an array
 element can be used instead of a named user variable.

The cardinality (number of elements) of array A is given by the expression |A|.

Example:
      array A[6]
      A[1] = 1
      A[2] = 2.0
      A[3] = {3.0, 3.0}
      A[4] = "four"
      A[6] = A[2]**3
      array B[6] = [ 1, 2.0, A[3], "four", , B[2]**3 ]

do for [i=1:6] { print A[i], B[i] }
          1 1
          2.0 2.0
          {3.0, 3.0} {3.0, 3.0}
          four four
          <undefined> <undefined>
          8.0 8.0

Note: Arrays and variables share the same namespace.  For example, assignment
 of a string variable named FOO will destroy any previously created array with
 name FOO.

The name of an array can be used in a `plot`, `splot`, `fit`, or `stats`
 command.  This is equivalent to providing a file in which column 1 holds the
 array index (from 1 to size), column 2 holds the value of real(A[i]) and
 column 3 holds the value of imag(A[i]).

Example:
      array A[200]
      do for [i=1:200] { A[i] = sin(i * pi/100.) }
      plot A title "sin(x) in centiradians"

When plotting the imaginary component of complex array values, it may be
 referenced either as imag(A[$1]) or as $3.  These two commands are equivalent

plot A using (real(A[$1])) : (imag(A[$1]))
      plot A using 2:3

?fonts
 Gnuplot does not provide any fonts of its own. It relies on external font
 handling, the details of which unfortunately vary from one terminal type to
 another. Brief documentation of font mechanisms that apply to more than one
 terminal type is given here. For information on font use by other individual
 terminals, see the documentation for that terminal.

Although it is possible to include non-alphabetic symbols by temporarily
 switching to a special font, e.g. the Adobe Symbol font, the preferred method
 is now to choose UTF-8 encoding and treat the symbol like any other character.
 Alternatively you can specify the unicode entry point for the desired symbol
 as an escape sequence in enhanced text mode.
 See `encoding`, `unicode`, `locale`, and `escape sequences`.

?fonts cairo
 These terminals find and access fonts using the external fontconfig tool set.
 Please see the
 It is usually sufficient in gnuplot to request a font by a generic name and
 size, letting fontconfig substitute a similar font if necessary. The following
 will probably all work:
      set term pdfcairo font "sans,12"
      set term pdfcairo font "Times,12"
      set term pdfcairo font "Times-New-Roman,12"

?gd
?fonts gd
 Font handling for the png, gif, jpeg, and sixelgd terminals is done by the
 library libgd.  Five basic fonts are provided directly by libgd. These are
 `tiny` (5x8 pixels), `small` (6x12 pixels), `medium`, (7x13 Bold), `large`
 (8x16) or `giant` (9x15 pixels). These fonts cannot be scaled or rotated.
 Use one of these keywords instead of the `font` keyword. E.g.
      set term png tiny

On most systems libgd also provides access to Adobe Type 1 fonts (*.pfa) and
 TrueType fonts (*.ttf). You must give the name of the font file, not the name
 of the font inside it, in the form "<face> {,<pointsize>}".
 <face> is either the full pathname to the font file, or the first part of a
 filename in one of the directories listed in the GDFONTPATH environmental
 variable. That is, 'set term png font "Face"' will look for a font file named
 either <somedirectory>/Face.ttf or <somedirectory>/Face.pfa.
 For example, if GDFONTPATH contains `/usr/local/fonts/ttf:/usr/local/fonts/pfa`
 then the following pairs of commands are equivalent
      set term png font "arial"
      set term png font "/usr/local/fonts/ttf/arial.ttf"
      set term png font "Helvetica"
      set term png font "/usr/local/fonts/pfa/Helvetica.pfa"
 To request a default font size at the same time:
      set term png font "arial,11"

Both TrueType and Adobe Type 1 fonts are fully scalable and rotatable.
 If no specific font is requested in the "set term" command, gnuplot checks
 the environmental variable GNUPLOT_DEFAULT_GDFONT to see if there is a
 preferred default font.
?fonts postscript
 PostScript font handling is done by the printer or viewing program.
 Gnuplot can create valid PostScript or encapsulated PostScript (*.eps) even if
 no fonts at all are installed on your computer.  Gnuplot simply refers to the
 font by name in the output file, and assumes that the printer or viewing
 program will know how to find or approximate a font by that name.

All PostScript printers or viewers should know about the standard set of Adobe
 fonts `Times-Roman`, `Helvetica`, `Courier`, and `Symbol`.  It is likely that
 many additional fonts are also available, but the specific set depends on your
 system or printer configuration. Gnuplot does not know or care about this;
 the output *.ps or *.eps files that it creates will simply refer to whatever
 font names you request.

Thus
      set term postscript eps font "Times-Roman,12"
 will produce output that is suitable for all printers and viewers.

On the other hand
      set term postscript eps font "Garamond-Premier-Pro-Italic"
 will produce an output file that contains valid PostScript, but since it
 refers to a specialized font, only some printers or viewers will be able to
 display the specific font that was requested.  Most will substitute a
 different font.

However, it is possible to embed a specific font in the output file so that
 all printers will be able to use it. This requires that the a suitable font
 description file is available on your system. Note that some font files require
 specific licensing if they are to be embedded in this way.
 See `postscript fontfile` for more detailed description and examples.
?glossary
 Throughout this document an attempt has been made to maintain consistency of
 nomenclature.  This cannot be wholly successful because as `gnuplot` has
 evolved over time, certain command and keyword names have been adopted that
 preclude such perfection.  This section contains explanations of the way
 some of these terms are used.

A "page" or "screen" or "canvas" is the entire area addressable by `gnuplot`.
 On a desktop it is a full window; on a plotter, it is a single sheet of paper;
 in svga mode it is the full monitor screen.

A screen may contain one or more "plots".  A plot is defined by an abscissa
 and an ordinate, although these need not actually appear on it, as well as
 the margins and any text written therein.

A plot contains one "graph".  A graph is defined by an abscissa and an
 ordinate, although these need not actually appear on it.

A graph may contain one or more "lines".  A line is a single function or
 data set.  "Line" is also a plotting style.  The word will also be used in
 sense "a line of text".  Presumably the context will remove any ambiguity.

The lines on a graph may have individual names.  These may be listed
 together with a sample of the plotting style used to represent them in
 the "key", sometimes also called the "legend".

The word "title" occurs with multiple meanings in `gnuplot`.  In this
 document, it will always be preceded by the adjective "plot", "line", or
 "key" to differentiate among them.
 A 2D graph may have up to four labeled `axes`.  The names of the four axes
 are "x" for the axis along the bottom border of the plot, "y" for the axis
 along the left border, "x2" for the top border, and "y2" for the right border.
 See `axes`.

A 3D graph may have up to three labeled `axes` -- "x", "y" and "z".  It is
 not possible to say where on the graph any particular axis will fall because
 you can change the direction from which the graph is seen with `set view`.

When discussing data files, the term "record" will be resurrected and used
 to denote a single line of text in the file, that is, the characters between
 newline or end-of-record characters.  A "point" is the datum extracted from
 a single record.  A "block" of data is a set of consecutive records delimited
 by blank records.  A line, when referred to in the context of a data file,
 is a subset of a block.  Note that the term "data block" may also be used to
 refer to a named block inline data (see `datablocks`).
?inline data
?inline
?datablocks
 There are two mechanisms for embedding data into a stream of gnuplot commands.
 If the special filename '-' appears in a plot command, then the lines
 immediately following the plot command are interpreted as inline data.
 See `special-filenames`.  Data provided in this way can only be used once, by
 the plot command it follows.

The second mechanism defines a named data block as a here-document.  The named
 data is persistent and may be referred to by more than one plot command.
 Example:
      $Mydata << EOD
      11 22 33 first line of data
      44 55 66 second line of data
      # comments work just as in a data file
      77 88 99
      EOD
      stats $Mydata using 1:3
      plot $Mydata using 1:3 with points, $Mydata using 1:2 with impulses

Data block names must begin with a $ character, which distinguishes them from
 other types of persistent variables.  The end-of-data delimiter (EOD in the
 example) may be any sequence of alphanumeric characters.

The storage associated with named data blocks can be released using `undefine`
 command. `undefine $*` frees all named data blocks at once.
?iteration
?iterate
 gnuplot supports command iteration and block-structured if/else/while/do
 constructs.  See `if`, `while`, and `do`.
 Simple iteration is possible inside `plot` or `set` commands.
 See `plot for`.  General iteration spanning multiple
 commands is possible using a block construct as shown below.
 For a related new feature, see the `summation` expression type.
 Here is an example using several of these new syntax features:
       set multiplot layout 2,2
       fourier(k, x) = sin(3./2*k)/k * 2./3*cos(k*x)
       do for [power = 0:3] {
           TERMS = 10**power
           set title sprintf("%g term Fourier series",TERMS)
           plot 0.5 + sum [k=1:TERMS] fourier(k,x) notitle
       }
       unset multiplot

Iteration is controlled by an iteration specifier with syntax

for [<var> in "string of N elements"]

for [<var> = <start> : <end> { : <increment> }]

In the first case <var> is a string variable that successively evaluates to
 single-word substrings 1 to N of the string in the iteration specifier.
 In the second case <start>, <end>, and <increment> are integers or integer
 expressions.

?scope
 With one exception, gnuplot variables are global.
 There is a single, persistent, list of active variables indexed by name.
 Assignment to a variable creates or replaces an entry in that list.
 The only way to remove a variable from that list is the `undefine` command.

The single exception to this is the variable used in an iteration specifier.
 The scope of the iteration variable is private to that iteration.
 You cannot permanently change the value of the iteration variable inside the
 iterated clause.  If the iteration variable has a value prior to iteration,
 that value will be retained or restored at the end of the iteration.
 For example, the following commands will print 1 2 3 4 5 6 7 8 9 10 A.

i = "A"
      do for [i=1:10] { print i; i=10; }
      print i

?linetypes
?colors
 In older gnuplot versions, each terminal type provided a set of distinct
 "linetypes" that could differ in color, in thickness, in dot/dash pattern, or
 in some combination of color and dot/dash.  These colors and patterns were not
 guaranteed to be consistent across different terminal types although most
 used the color sequence red/green/blue/magenta/cyan/yellow.  You can select
 this old behaviour via the command `set colorsequence classic`, but by default
 gnuplot version 5 uses a terminal-independent sequence of 8 colors.

You can further customize the sequence of linetype properties interactively or
 in an initialization file.  See `set linetype`.  Several sample initialization
 files are provided in the distribution package.

The current linetype properties for a particular terminal can be previewed by
 issuing the `test` command after setting the terminal type.

Successive functions or datafiles plotted by a single command will be assigned
 successive linetypes in the current default sequence.  You can override this
 for any individual function, datafile, or plot element by giving explicit line
 properties in the plot command.

Examples:

plot "foo", "bar"                 # plot two files using linetypes 1, 2
      plot sin(x) linetype 4            # use linetype color 4

In general, colors can be specified using named colors, rgb (red, green, blue)
 components, hsv (hue, saturation, value) components, or a coordinate along the
 current pm3d palette.

Examples:

plot sin(x) lt rgb "violet"       # one of gnuplot's named colors
      plot sin(x) lt rgb "#FF00FF"      # explicit RGB triple in hexadecimal
      plot sin(x) lt palette cb -45     # whatever color corresponds to -45
                                        # in the current cbrange of the palette
      plot sin(x) lt palette frac 0.3   # fractional value along the palette

See `colorspec`, `show colornames`, `hsv`, `set palette`, `cbrange`.
 See also `set monochrome`.

Linetypes also have an associated dot-dash pattern although not all terminal
 types are capable of using it. Gnuplot version 5 allows you to specify the
 dot-dash pattern independent of the line color. See `dashtype`.

?colorspec
?rgbcolor
?lc
?linecolor
?tc
?textcolor
 Many commands allow you to specify a linetype with an explicit color.

Syntax:

... {linecolor | lc} {"colorname" | <colorspec> | <n>}
       ... {textcolor | tc} {<colorspec> | {linetype | lt} <n>}
       ... {fillcolor | fc} {<colorspec> | linetype <n> | linestyle <n>}

where <colorspec> has one of the following forms:

rgbcolor "colorname"    # e.g. "blue"
       rgbcolor "0xRRGGBB"     # string containing hexadecimal constant
       rgbcolor "0xAARRGGBB"   # string containing hexadecimal constant
       rgbcolor "#RRGGBB"      # string containing hexadecimal in x11 format
       rgbcolor "#AARRGGBB"    # string containing hexadecimal in x11 format
       rgbcolor <integer val>  # integer value representing AARRGGBB
       rgbcolor variable       # integer value is read from input file
       palette frac <val>      # <val> runs from 0 to 1
       palette cb <value>      # <val> lies within cbrange
       palette z
       variable                # color index is read from input file
       bgnd                    # background color
       black

The "<n>" is the linetype number the color of which is used, see `test`.

"colorname" refers to one of the color names built in to gnuplot. For a list
 of the available names, see `show colornames`.

Hexadecimal constants can be given in quotes as "#RRGGBB" or "0xRRGGBB", where
 RRGGBB represents the red, green, and blue components of the color and must be
 between 00 and FF.  For example, magenta = full-scale red + full-scale blue
 could be represented by "0xFF00FF", which is the hexadecimal representation of
 (255 << 16) + (0 << 8) + (255).

"#AARRGGBB" represents an RGB color with an alpha channel (transparency)
 value in the high bits. An alpha value of 0 represents a fully opaque color;
 i.e., "#00RRGGBB" is the same as "#RRGGBB".  An alpha value of 255 (FF)
 represents full transparency.

The color palette is a linear gradient of colors that smoothly maps a
 single numerical value onto a particular color.  Two such mappings are always
 in effect. `palette frac`  maps a fractional value between 0 and 1 onto the
 full range of the color palette.  `palette cb` maps the range of the color
 axis onto the same palette.  See `set cbrange`.  See also `set colorbox`.
 You can use either of these to select a constant color from the current
 palette.

"palette z" maps the z value of each plot segment or plot element into the
 cbrange mapping of the palette. This allows smoothly-varying color along a
 3d line or surface. It also allows coloring 2D plots by palette values read
 from an extra column of data (not all 2D plot styles allow an extra column).
 There are two special color specifiers: `bgnd` for background color and `black`.
?background
?bgnd
 Most terminals allow you to set an explicit background color for the plot.
 The special linetype `bgnd` will draw in this color, and `bgnd` is also
 recognized as a color.
 Examples:
      # This will erase a section of the canvas by writing over it in the
      # background color
      set term wxt background rgb "gray75"
      set object 1 rectangle from x0,y0 to x1,y1 fillstyle solid fillcolor bgnd
      # This will draw an "invisible" line along the x axis
      plot 0 lt bgnd
?linecolor variable
?lc variable
?textcolor variable
?tc variable
?variable linecolor
 `lc variable` tells the program to use the value read from one column of the
 input data as a linetype index, and use the color belonging to that linetype.
 This requires a corresponding additional column in the `using` specifier.
 Text colors can be set similarly using `tc variable`.

Examples:
       # Use the third column of data to assign colors to individual points
       plot 'data' using 1:2:3 with points lc variable

# A single data file may contain multiple sets of data, separated by two
       # blank lines.  Each data set is assigned as index value (see `index`)
       # that can be retrieved via the `using` specifier `column(-2)`.
       # See `pseudocolumns`.  This example uses to value in column -2 to
       # draw each data set in a different line color.
       plot 'data' using 1:2:(column(-2)) with lines lc variable

?rgbcolor variable
?lc rgbcolor variable
?tc rgbcolor variable
?variable rgbcolor
?variable textcolor
 You can assign a separate color for each data point, line segment, or label in
 your plot.  `lc rgbcolor variable` tells the program to read RGB color
 information for each line in the data file. This requires a corresponding
 additional column in the `using` specifier.  The extra column is interpreted as
 a 24-bit packed RGB triple. If the value is provided directly in the data file
 it is easiest to give it as a hexadecimal value (see `rgbcolor`).
 Alternatively, the `using` specifier can contain an expression that evaluates
 to a 24-bit RGB color as in the example below.
 Text colors are similarly set using `tc rgbcolor variable`.

Example:
       # Place colored points in 3D at the x,y,z coordinates corresponding to
       # their red, green, and blue components
       rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
       splot "data" using 1:2:3:(rgb($1,$2,$3)) with points lc rgb variable

?dashtype
 In gnuplot version 5 the dash pattern (`dashtype`) is a separate property
 associated with each line, analogous to `linecolor` or `linewidth`.  It is not
 necessary to place the current terminal in a special mode just to draw dashed
 lines.  I.e. the command `set term <termname> {solid|dashed}` is now ignored.
 If backwards compatibility with old scripts written for version 4 is required,
 the following lines can be used instead:

if (GPVAL_VERSION >= 5.0) set for [i=1:9] linetype i dashtype i
      if (GPVAL_VERSION < 5.0) set termoption dashed

All lines have the property `dashtype solid` unless you specify otherwise.
 You can change the default for a particular linetype using the command
 `set linetype` so that it affects all subsequent commands, or you can include
 the desired dashtype as part of the `plot` or other command.

Syntax:
       dashtype N          # predefined dashtype invoked by number
       dashtype "pattern"  # string containing a combination of the characters
                           # dot (.) hyphen (-) underscore(_) and space.
       dashtype (s1,e1,s2,e2,s3,e3,s4,e4)  # dash pattern specified by 1 to 4
                           # numerical pairs <solid length>, <emptyspace length>

Example:
       # Two functions using linetype 1 but distinguished by dashtype
       plot f1(x) with lines lt 1 dt solid, f2(x) with lines lt 1 dt 3

Some terminals support user-defined dash patterns in addition to whatever
 set of predefined dash patterns they offer.

Examples:
      plot f(x) dt 3            # use terminal-specific dash pattern 3
      plot f(x) dt ".. "        # construct a dash pattern on the spot
      plot f(x) dt (2,5,2,15)   # numerical representation of the same pattern
      set dashtype 11 (2,4,4,7) # define new dashtype to be called by index
      plot f(x) dt 11           # plot using our new dashtype

If you specify a dash pattern using a string the program will convert this to
 a sequence of <solid>,<empty> pairs. Dot "." becomes (2,5), dash "-" becomes
 (10,10), underscore "_" becomes (20,10), and each space character " " adds 10
 to the previous <empty> value.  The command `show dashtype` will show both the
 original string and the converted numerical sequence.

?linestyles vs linetypes
 A `linestyle` is a temporary association of properties linecolor, linewidth,
 dashtype, and pointtype.  It is defined using the command `set style line`.
 Once you have defined a linestyle, you can use it in a plot command to control
 the appearance of one or more plot elements.  In other words, it is just like
 a linetype except for its lifetime.  Whereas `linetypes` are permanent (they
 last until you explicitly redefine them), `linestyles` last until the next
 reset of the graphics state.

Examples:

# define a new line style with terminal-independent color cyan,
      # linewidth 3, and associated point type 6 (a circle with a dot in it).
      set style line 5 lt rgb "cyan" lw 3 pt 6
      plot sin(x) with linespoints ls 5          # user-defined line style 5

?layers
?behind
?front
?back
 A gnuplot plot is built up by drawing its various components in a fixed order.
 This order can be modified by assigning some components to a specific layer
 using the keywords `behind`, `back`, or `front`. For example, to replace the
 background color of the plot area you could define a colored rectangle with the
 attribute `behind`.
      set object 1 rectangle from graph 0,0 to graph 1,1 fc rgb "gray" behind
 The order of drawing is
      behind
      back
      the plot itself
      the plot legend (`key`)
      front
 Within each layer elements are drawn in the order
      grid, axis, and border elements
      pixmaps in numerical order
      objects (rectangles, circles, ellipses, polygons) in numerical order
      labels in numerical order
      arrows in numerical order
 In the case of multiple plots on a single page (multiplot mode) this order
 applies separately to each component plot, not to the multiplot as a whole.
?mouse input
 Many terminals allow interaction with the current plot using the mouse. Some
 also support the definition of hotkeys to activate pre-defined functions by
 hitting a single key while the mouse focus is in the active plot window.
 It is even possible to combine mouse input with `batch` command scripts, by
 invoking the command `pause mouse` and then using the mouse variables returned
 by mouse clicking as parameters for subsequent scripted actions.
 See `bind` and `mouse variables`.  See also the command `set mouse`.
?commands bind
?hotkey
?hotkeys
?bind
 Syntax:
       bind {allwindows} [<key-sequence>] ["<gnuplot commands>"]
       bind <key-sequence> ""
       reset bind

The `bind` allows defining or redefining a hotkey, i.e. a sequence of gnuplot
 commands which will be executed when a certain key or key sequence is pressed
 while the driver's window has the input focus. Note that `bind` is only
 available if gnuplot was compiled with `mouse` support and it is used by all
 mouse-capable terminals. A user-specified binding supersedes any builtin
 bindings, except that <space> and 'q' cannot normally be rebound. For an
 exception, see `bind space`.

Only mouse button 1 can be bound, and only for 2D plots.

You get the list of all hotkeys by typing `show bind` or `bind` or by typing
 the hotkey 'h' in the graph window.

Key bindings are restored to their default state by `reset bind`.

Note that multikey-bindings with modifiers must be given in quotes.

Normally hotkeys are only recognized when the currently active plot window
 has focus. `bind allwindows <key> ...` (short form: `bind all <key> ...`)
 causes the binding for <key> to apply to all gnuplot plot windows, active
 or not.  In this case gnuplot variable MOUSE_KEY_WINDOW is set to the ID
 of the originating window, and may be used by the bound command.

Examples:

- set bindings:

bind a "replot"
     bind "ctrl-a" "plot x*x"
     bind "ctrl-alt-a" 'print "great"'
     bind Home "set view 60,30; replot"
     bind all Home 'print "This is window ",MOUSE_KEY_WINDOW'

- show bindings:
     bind "ctrl-a"          # shows the binding for ctrl-a
     bind                   # shows all bindings
     show bind              # show all bindings

- remove bindings:
     bind "ctrl-alt-a" ""   # removes binding for ctrl-alt-a
                              (note that builtins cannot be removed)
     reset bind             # installs default (builtin) bindings

- bind a key to toggle something:
   v=0
   bind "ctrl-r" "v=v+1;if(v%2)set term x11 noraise; else set term x11 raise"

Modifiers (ctrl / alt) are case insensitive, keys not:
     ctrl-alt-a == CtRl-alT-a
     ctrl-alt-a != ctrl-alt-A

List of modifiers (alt == meta):
     ctrl, alt, shift (only valid for Button1 Button2 Button3)

List of supported special keys:

"BackSpace", "Tab", "Linefeed", "Clear", "Return", "Pause", "Scroll_Lock",
    "Sys_Req", "Escape", "Delete", "Home", "Left", "Up", "Right", "Down",
    "PageUp", "PageDown", "End", "Begin",

"KP_Space", "KP_Tab", "KP_Enter", "KP_F1", "KP_F2", "KP_F3", "KP_F4",
    "KP_Home", "KP_Left", "KP_Up", "KP_Right", "KP_Down", "KP_PageUp",
    "KP_PageDown", "KP_End", "KP_Begin", "KP_Insert", "KP_Delete", "KP_Equal",
    "KP_Multiply", "KP_Add", "KP_Separator", "KP_Subtract", "KP_Decimal",
    "KP_Divide",

"KP_1" - "KP_9", "F1" - "F12"

The following are window events rather than actual keys

"Button1" "Button2" "Button3" "Close"

See also help for `mouse`.
?commands bind space
?bind space
 If gnuplot was built with configuration option --enable-raise-console, then
 typing <space> in the plot window raises gnuplot's command window. This hotkey
 can be changed to ctrl-space by starting gnuplot as 'gnuplot -ctrlq', or by
 setting the XResource 'gnuplot*ctrlq'.  See `x11 command-line-options`.
?mouse variables
 When `mousing` is active, clicking in the active window will set several user
 variables that can be accessed from the gnuplot command line. The coordinates
 of the mouse at the time of the click are stored in MOUSE_X MOUSE_Y MOUSE_X2
 and MOUSE_Y2. The mouse button clicked, and any meta-keys active at that time,
 are stored in MOUSE_BUTTON MOUSE_SHIFT MOUSE_ALT and MOUSE_CTRL.  These
 variables are set to undefined at the start of every plot, and only become
 defined in the event of a mouse click in the active plot window. To determine
 from a script if the mouse has been clicked in the active plot window, it is
 sufficient to test for any one of these variables being defined.

plot 'something'
       pause mouse
       if (exists("MOUSE_BUTTON")) call 'something_else'; \
       else print "No mouse click."

It is also possible to track keystrokes in the plot window using the mousing
 code.

plot 'something'
       pause mouse keypress
       print "Keystroke ", MOUSE_KEY, " at ", MOUSE_X, " ", MOUSE_Y

When `pause mouse keypress` is terminated by a keypress, then MOUSE_KEY will
 contain the ascii character value of the key that was pressed. MOUSE_CHAR will
 contain the character itself as a string variable.  If the pause command is
 terminated abnormally (e.g. by ctrl-C or by externally closing the plot window)
 then MOUSE_KEY will equal -1.

Note that after a zoom by mouse, you can read the new ranges as GPVAL_X_MIN,
 GPVAL_X_MAX, GPVAL_Y_MIN, and GPVAL_Y_MAX, see `gnuplot-defined variables`.
?persist
 Many gnuplot terminals (aqua, pm, qt, x11, windows, wxt, ...) open separate
 display windows on the screen into which plots are drawn.  The `persist` option
 tells gnuplot to leave these windows open when the main program exits.
 It has no effect on non-interactive terminal output.
 For example if you issue the command

gnuplot -persist -e 'plot [-5:5] sinh(x)'

gnuplot will open a display window, draw the plot into it, and then exit,
 leaving the display window containing the plot on the screen.
 You can also specify `persist` or `nopersist` when you set a new terminal.

set term qt persist size 700,500

Depending on the terminal type, some mousing operations may still be possible
 in the persistent window.  However operations like zoom/unzoom that require
 redrawing the plot are not possible because the main program has exited.
 If you want to leave a plot window open and fully mouseable after creating
 the plot, for example when running gnuplot from a script file rather than
 interactively, see `pause mouse close`.

?plotting
 There are four `gnuplot` commands which actually create a plot: `plot`,
 `splot`, `replot`, and `refresh`.  Other commands control the layout, style,
 and content of the plot that will eventually be created.
 `plot` generates 2D plots. `splot` generates 3D plots (actually 2D projections,
 of course). `replot` reexecutes the previous `plot` or `splot` command.
 `refresh` is similar to `replot` but it reuses any previously stored data
 rather than rereading data from a file or input stream.

Each time you issue one of these four commands it will redraw the screen or
 generate a new page of output containing all of the currently defined axes,
 labels, titles, and all of the various functions or data sources listed in the
 original plot command. If instead you need to place several complete plots next
 to each other on the same page, e.g. to make a panel of sub-figures or to inset
 a small plot inside a larger plot, use the command `set multiplot` to suppress
 generation of a new page for each plot command.

Much of the general information about plotting can be found in the discussion
 of `plot`; information specific to 3D can be found in the `splot` section.

`plot` operates in either rectangular or polar coordinates -- see `set polar`.
 `splot` operates in Cartesian coordinates, but will accept azimuthal or
 cylindrical coordinates on input. See `set mapping`.
 `plot` also lets you use each of the four borders -- x (bottom), x2 (top), y
 (left) and y2 (right) -- as an independent axis.  The `axes` option lets you
 choose which pair of axes a given function or data set is plotted against.  A
 full complement of `set` commands exists to give you complete control over
 the scales and labeling of each axis.  Some commands have the name of an
 axis built into their names, such as `set xlabel`.  Other commands have one
 or more axis names as options, such as `set logscale xy`.  Commands and
 options controlling the z axis have no effect on 2D graphs.

`splot` can plot surfaces and contours in addition to points and/or lines.
 See `set isosamples` for information about defining the grid for a 3D function.
 See `splot datafile` for information about the requisite file structure for 3D
 data. For contours see `set contour`, `set cntrlabel`, and `set cntrparam`.

In `splot`, control over the scales and labels of the axes are the same as
 with `plot` except that there is also a z axis and labeling the x2 and y2 axes
 is possible only for pseudo-2D plots created using `set view map`.
?plugins
?uigamma
 The set of functions available for plotting or for evaluating expressions
 can be extended through a plugin mechanism that imports executable functions
 from a shared library.  For example, gnuplot versions through 5.4 do not
 provide a built-in implementation of the upper incomplete gamma function
 Q(a,x).
 You could define an approximation directly in gnuplot like this:
       Q(a,x) = 1. - igamma(a,x)
 However this has inherently limited precision as the value of Q approaches 1.
 If you need a more accurate implementation, it would be better to provide one
 via a plugin (see below).  Once imported, the function can be used just as any
 other built-in or user-defined function in gnuplot.
 See `import`.

The gnuplot distribution includes source code and instructions for creating
 a plugin library in the directory demo/plugin.  You can modify the simple
 example file `demo_plugin.c` by replacing one or more of the toy example
 functions with an implementation of the function you are interested in.
 This could include invocation of functions from an external mathematical
 library.

The demo/plugin directory also contains source for a plugin that implements
 Q(a,x). As noted above, this plugin allows earlier versions of gnuplot to
 provide the same function `uigamma` as the current development version.
      import Q(a,x) from "uigamma_plugin"
      uigamma(a,x) = ((x<1 || x<a) ? 1.0-igamma(a,x) : Q(a,x))

?startup
?start
?start-up
?initialization
?.gnuplot
 When gnuplot is run, it first looks for a system-wide initialization file
 `gnuplotrc`.  The location of this file is determined when the program is built
 and is reported by `show loadpath`.  The program then looks in the user's HOME
 directory for a file called `.gnuplot` on Unix-like systems or `GNUPLOT.INI` on
 other systems.  (OS/2 will look for it in the directory named in
 the environment variable `GNUPLOT`; Windows will use `APPDATA`).
 Note: The program can be configured to look first in the current directory,
 but this is not recommended because it is bad security practice.
?string
?strings
 In addition to string constants, most gnuplot commands also accept a string
 variable, a string expression, or a function that returns a string.
 For example, the following four methods of creating a plot all result in the
 same plot title:

four = "4"
       graph4 = "Title for plot #4"
       graph(n) = sprintf("Title for plot #%d",n)

plot 'data.4' title "Title for plot #4"
       plot 'data.4' title graph4
       plot 'data.4' title "Title for plot #".four
       plot 'data.4' title graph(4)

Since integers are promoted to strings when operated on by the string
 concatenation operator ('.' character), the following method also works:

N = 4
       plot 'data.'.N title "Title for plot #".N

In general, elements on the command line will only be evaluated as possible
 string variables if they are not otherwise recognizable as part of the normal
 gnuplot syntax. So the following sequence of commands is legal, although
 probably should be avoided so as not to cause confusion:

plot = "my_datafile.dat"
       title = "My Title"
       plot plot title title
?string substring
 Substrings can be specified by appending a range specifier to any string,
 string variable, or string-valued function.  The range specifier has the
 form [begin:end], where begin is the index of the first character of the
 substring and end is the index of the last character of the substring.
 The first character has index 1.  The begin or end fields may be empty, or
 contain '*', to indicate the true start or end of the original string.
 E.g.  str[:] and str[*:*] both describe the full string str.
?string operators
 Three binary operators require string operands: the string concatenation
 operator ".", the string equality operator "eq" and the string inequality
 operator "ne".  The following example will print TRUE.

if ("A"."B" eq "AB") print "TRUE"
?string functions
 Gnuplot provides several built-in functions that operate on strings.
 General formatting functions: see `gprintf` `sprintf`.
 Time formatting functions: see `strftime` `strptime`.
 String manipulation: see `substr` `strstrt` `trim` `word` `words`.
?string encoding
 Gnuplot's built-in string manipulation functions are sensitive to utf-8
 encoding (see `set encoding`). For example

utf8string = "αβγ"
  strlen(utf8string) returns 3 (number of characters, not number of bytes)
  utf8string[2:2] evaluates to "β"
  strstrt(utf8string,"β") evaluates to 2

?substitution
 When a command line to gnuplot is first read, i.e. before it is interpreted
 or executed, two forms of lexical substitution are performed. These are
 triggered by the presence of text in backquotes (ascii character 96) or
 preceded by @ (ascii character 64).
?substitution backquotes
?backquotes
?shell commands
 Command-line substitution is specified by a system command enclosed in
 backquotes.  This command is spawned and the output it produces replaces
 the backquoted text on the command line.  Exit status of the system command
 is returned in variables GPVAL_SYSTEM_ERRNO and GPVAL_SYSTEM_ERRMSG.

CHANGE (differs from versions 4 through 5.2): Internal carriage-return ('\r')
 and newline ('\n') characters are not stripped from the input stream during
 substitution.  This change brings backquote substitution in line with the
 system() function.

Command-line substitution can be used anywhere on the `gnuplot` command
 line except inside strings delimited by single quotes.

Example:

This will run the program `leastsq` and replace `leastsq` (including
 backquotes) on the command line with its output:
       f(x) = `leastsq`

or, in VMS
       f(x) = `run leastsq`

These will generate labels with the current time and userid:
       set label "generated on `date +%Y-%m-%d` by `whoami`" at 1,1
       set timestamp "generated on %Y-%m-%d by `whoami`"
?substitution macros
?macros
 The character @ is used to trigger substitution of the current value of a
 string variable into the command line. The text in the string variable may
 contain any number of lexical elements.  This allows string variables to be
 used as command line macros.  Only string constants may be expanded using this
 mechanism, not string-valued expressions.
 For example:

style1 = "lines lt 4 lw 2"
       style2 = "points lt 3 pt 5 ps 2"
       range1 = "using 1:3"
       range2 = "using 1:5"
       plot "foo" @range1 with @style1, "bar" @range2 with @style2

The line containing @ symbols is expanded on input, so that by the time it is
 executed the effect is identical to having typed in full

plot "foo" using 1:3 with lines lt 4 lw 2, \
            "bar" using 1:5 with points lt 3 pt 5 ps 2

The function exists() may be useful in connection with macro evaluation.
 The following example checks that C can safely be expanded as the name of
 a user-defined variable:

C = "pi"
       if (exists(C)) print C," = ", @C

Macro expansion does not occur inside either single or double quotes.
 However macro expansion does occur inside backquotes.

Macro expansion is handled as the very first thing the interpreter does when
 looking at a new line of commands and is only done once. Therefore, code like
 the following will execute correctly:

A = "c=1"
      @A

but this line will not, since the macro is defined on the same line
 and will not be expanded in time

A = "c=1"; @A   # will not expand to c=1

Macro expansion inside a bracketed iteration occurs before the loop is
 executed; i.e. @A will always act as the original value of A even if A itself
 is reassigned inside the loop.

For execution of complete commands the `evaluate` command may also be handy.
?mixing_macros_backquotes
?substitution mixing_macros_backquotes
 The interaction of string variables, backquotes and macro substitution is
 somewhat complicated.  Backquotes do not block macro substitution, so

filename = "mydata.inp"
       lines = ` wc --lines @filename | sed "s/ .*//" `

results in the number of lines in mydata.inp being stored in the integer
 variable lines. And double quotes do not block backquote substitution, so

mycomputer = "`uname -n`"

results in the string returned by the system command `uname -n` being stored
 in the string variable mycomputer.

However, macro substitution is not performed inside double quotes, so you
 cannot define a system command as a macro and then use both macro and backquote
 substitution at the same time.

machine_id = "uname -n"
        mycomputer = "`@machine_id`"  # doesn't work!!

This fails because the double quotes prevent @machine_id from being interpreted
 as a macro. To store a system command as a macro and execute it later you must
 instead include the backquotes as part of the macro itself.  This is
 accomplished by defining the macro as shown below.  Notice that the sprintf
 format nests all three types of quotes.

machine_id = sprintf('"`uname -n`"')
       mycomputer = @machine_id
?syntax
?specify
?punctuation
 Options and any accompanying parameters are separated by spaces whereas lists
 and coordinates are separated by commas.  Ranges are separated by colons and
 enclosed in brackets [], text and file names are enclosed in quotes, and a
 few miscellaneous things are enclosed in parentheses.

Commas are used to separate coordinates on the `set` commands `arrow`,
 `key`, and `label`; the list of variables being fitted (the list after the
 `via` keyword on the `fit` command); lists of discrete contours or the loop
 parameters which specify them on the `set cntrparam` command; the arguments
 of the `set` commands `dgrid3d`, `dummy`, `isosamples`, `offsets`, `origin`,
 `samples`, `size`, `time`, and `view`; lists of tics or the loop parameters
 which specify them; the offsets for titles and axis labels; parametric
 functions to be used to calculate the x, y, and z coordinates on the `plot`,
 `replot` and `splot` commands; and the complete sets of keywords specifying
 individual plots (data sets or functions) on the `plot`, `replot` and `splot`
 commands.

Parentheses are used to delimit sets of explicit tics (as opposed to loop
 parameters) and to indicate computations in the `using` filter of the `fit`,
 `plot`, `replot` and `splot` commands.

(Parentheses and commas are also used as usual in function notation.)

Square brackets are used to delimit ranges given in `set`, `plot`
 or `splot` commands.

Colons are used to separate extrema in `range` specifications (whether they
 are given on `set`, `plot` or `splot` commands) and to separate entries in
 the `using` filter of the `plot`, `replot`, `splot` and `fit` commands.

Semicolons are used to separate commands given on a single command line.

Curly braces are used in the syntax for enhanced text mode and to delimit
 blocks in if/then/else statements.  They are also used to denote complex
 numbers: {3,2} = 3 + 2i.
?quotes
?syntax quotes
 Gnuplot uses three forms of quote marks for delimiting text strings,
 double-quote (ascii 34), single-quote (ascii 39), and backquote (ascii 96).

Filenames may be entered with either single- or double-quotes.  In this
 manual the command examples generally single-quote filenames and double-quote
 other string tokens for clarity.

String constants and text strings used for labels, titles, or other plot
 elements may be enclosed in either single quotes or double quotes. Further
 processing of the quoted text depends on the choice of quote marks.

Backslash processing of special characters like \n (newline) and
 \345 (octal character code) is performed only for double-quoted strings.
 In single-quoted strings, backslashes are just ordinary characters.  To get
 a single-quote (ascii 39) in a single-quoted string, it must be doubled.
 Thus the strings "d\" s' b\\" and 'd" s'' b\' are completely equivalent.

Text justification is the same for each line of a multi-line string.
 Thus the center-justified string
       "This is the first line of text.\nThis is the second line."
 will produce
                        This is the first line of text.
                           This is the second line.
 but
       'This is the first line of text.\nThis is the second line.'
 will produce
           This is the first line of text.\nThis is the second line.

Enhanced text processing is performed for both double-quoted text and
 single-quoted text, but only by terminals supporting this mode.
 See `enhanced text`.

Back-quotes are used to enclose system commands for substitution into the
 command line.  See `substitution`.
?time/date
 `gnuplot` supports the use of time and/or date information as input data.
 This feature is activated by the commands `set xdata time`, `set ydata time`,
 etc.

Internally all times and dates are converted to the number of seconds from
 the year 1970.  The command `set timefmt` defines the default format for all
 inputs: data files, ranges, tics, label positions -- anything that accepts a
 time data value defaults to receiving it in this format.  Only one default
 format can be in effect at a given time. Thus if both x and y data in a file
 are time/date, by default they are interpreted in the same format. However
 this default can be replaced when reading any particular file or column of
 input using the `timecolumn` function in the corresponding `using` specifier.

The conversion to and from seconds assumes Universal Time (which is the same
 as Greenwich Standard Time).  There is no provision for changing the time
 zone or for daylight savings.  If all your data refer to the same time zone
 (and are all either daylight or standard) you don't need to worry about these
 things.  But if the absolute time is crucial for your application, you'll
 need to convert to UT yourself.

Commands like `show xrange` will re-interpret the integer according to
 `timefmt`.  If you change `timefmt`, and then `show` the quantity again, it
 will be displayed in the new `timefmt`.  For that matter, if you reset the
 data type flag for that axis (e.g. `set xdata`), the quantity will be shown
 in its numerical form.

The commands `set format` or `set tics format` define the format that will be
 used for tic labels, whether or not input for the specified axis is time/date.

If time/date information is to be plotted from a file, the `using` option
 _must_ be used on the `plot` or `splot` command.  These commands simply use
 white space to separate columns, but white space may be embedded within the
 time/date string.  If you use tabs as a separator, some trial-and-error may
 be necessary to discover how your system treats them.

The `time` function can be used to get the current system time. This value
 can be converted to a date string with the `strftime` function, or it can be
 used in conjunction with `timecolumn` to generate relative time/date plots.
 The type of the argument determines what is returned. If the argument is an
 integer, `time` returns the current time as an integer, in seconds from
 1 Jan 1970. If the argument is real (or complex), the result is real as well.
 The precision of the fractional (sub-second) part depends on your operating
 system. If the argument is a string, it is assumed to be a format string,
 and it is passed to `strftime` to provide a formatted time/date string.

The following example demonstrates time/date plotting.

Suppose the file "data" contains records like

03/21/95 10:00  6.02e23

This file can be plotted by

set xdata time
       set timefmt "%m/%d/%y"
       set xrange ["03/21/95":"03/22/95"]
       set format x "%m/%d"
       set timefmt "%m/%d/%y %H:%M"
       plot "data" using 1:3

which will produce xtic labels that look like "03/21".

Gnuplot tracks time to millisecond precision. Time formats have been
 modified to match this.
 Example: print the current time to msec precision
      print strftime("%H:%M:%.3S %d-%b-%Y",time(0.0))
      18:15:04.253 16-Apr-2011

See `time_specifiers`.
?plotting styles

Many plotting styles are available in gnuplot.
 They are listed alphabetically below.
 The commands `set style data` and `set style function` change the
 default plotting style for subsequent `plot` and `splot` commands.

You can also specify the plot style explicitly as part of
 the `plot` or `splot` command.  If you want to mix plot styles within a
 single plot, you must specify the plot style for each component.

Example:

plot 'data' with boxes, sin(x) with lines

Each plot style has its own expected set of data entries in a data file.
 For example, by default the `lines` style expects either a single column of
 y values (with implicit x ordering) or a pair of columns with x in the first
 and y in the second.  For more information on how to fine-tune how columns in a
 file are interpreted as plot data, see `using`.

?plotting styles arrows
?style arrows
?with arrows
?arrows
 The 2D `arrows` style draws an arrow with specified length and orientation
 angle at each point (x,y).  Additional input columns may be used to provide
 variable (per-datapoint) color information or arrow style.
 It is identical to the 2D style `with vectors` except that each the arrow
 head is positioned using length + angle rather than delta_x + delta_y.
 See `with vectors`.

4 columns:  x  y  length  angle

The keywords `with arrows` may be followed by inline arrow style properties,
 a reference to a predefined arrow style, or `arrowstyle variable` to load the
 index of the desired arrow style for each arrow from a separate column.

`length` > 0 is interpreted in x-axis coordinates.
 -1 < `length` < 0 is interpreted in horizontal graph coordinates; i.e. |length|
 is a fraction of the total graph width.
 The program will adjust for differences in x and y scaling or plot aspect ratio
 so that the visual length is independent of the orientation angle.

`angle` is always specified in degrees.
?beeswarm
?bee swarm
 "Bee swarm" plots result from applying jitter to separate overlapping points.
 A typical use is to compare the distribution of y values exhibited by two or
 more categories of points, where the category determines the x coordinate.
 See the `set jitter` command for how to control the overlap criteria and the
 displacement pattern used for jittering.  The plots in the figure were created
 by the same plot command but different jitter settings.

set jitter
      plot $data using 1:2:1 with points lc variable
?plotting styles boxerrorbars
?style boxerrorbars
?with boxerrorbars
?boxerrorbars
 The `boxerrorbars` style is only relevant to 2D data plotting.  It is a
 combination of the `boxes` and `yerrorbars` styles.  It requires 3, 4, or 5
 columns of data.
 An additional (4th, 5th or 6th) input column may be used to provide variable
 (per-datapoint) color information (see `linecolor` and `rgbcolor variable`).
 The error bar will be drawn in the same color as the border of the box.

3 columns:  x  y  ydelta
      4 columns:  x  y  ydelta xdelta        # boxwidth != -2
      4 columns:  x  y  ylow  yhigh          # boxwidth == -2
      5 columns:  x  y  ylow  yhigh  xdelta

The boxwidth will come from the fourth column if the y errors are given as
 "ydelta" and the boxwidth was not previously set to -2.0 (`set boxwidth -2.0`)
 or from the fifth column if the y errors are in the form of "ylow yhigh".  The
 special case  `boxwidth = -2.0` is for four-column data with y errors in the
 form "ylow yhigh".  In this case the boxwidth will be calculated so that each
 box touches the adjacent boxes.  The width will also be calculated in cases
 where three-column data are used.

The box height is determined from the y error in the same way as it is for
 the `yerrorbars` style---either from y-ydelta to y+ydelta or from ylow to
 yhigh, depending on how many data columns are provided.
?plotting styles boxes
?style boxes
?with boxes
?boxes
 In 2D plots the `boxes` style draws a rectangle centered about the given
 x coordinate that extends from the x axis, i.e. from y=0 not from the graph
 border, to the given y coordinate.  The width of the box can be provided in
 an additional input column or controlled by `set boxwidth`.  Otherwise each
 box extends to touch the adjacent boxes.

In 3D plots the `boxes` style draws a box centered at the given [x,y]
 coordinate that extends from the plane at z=0 to the given z coordinate.
 The width of the box on x can be provided in a separate input column or via
 `set boxwidth`.  The depth of the box on y is controlled by `set boxdepth`.
 Boxes do not automatically expand to touch each other as in 2D plots.
?style boxes 2D
?boxes 2D

`plot with boxes` uses 2 or 3 columns of basic data.  Additional input columns
 may be used to provide information such as variable line or fill color.
 See `rgbcolor variable`.

2 columns:  x  y
      3 columns:  x  y  x_width

The width of the box is obtained in one of three ways.  If the input data has a
 third column, this will be used to set the box width.  Otherwise if a width has
 been set using the `set boxwidth` command, this will be used.  If neither of
 these is available, the width of each box will be calculated so that it touches
 the adjacent boxes.

The box interiors are drawn using the current fillstyle.
 Alternatively a fillstyle may be specified in the plot command.
 See `set style fill`.
 If no fillcolor is given in the plot command, the current line color is used.

Examples:

To plot a data file with solid filled boxes with a small vertical space
 separating them (bargraph):

set boxwidth 0.9 relative
       set style fill solid 1.0
       plot 'file.dat' with boxes

To plot a sine and a cosine curve in pattern-filled boxes style:

set style fill pattern
       plot sin(x) with boxes, cos(x) with boxes

The sin plot will use pattern 0; the cos plot will use pattern 1.
 Any additional plots would cycle through the patterns supported by the
 terminal driver.

To specify explicit fillstyles and fillcolors for each dataset:

plot 'file1' with boxes fs solid 0.25 fc 'cyan', \
           'file2' with boxes fs solid 0.50 fc 'blue', \
           'file3' with boxes fs solid 0.75 fc 'magenta', \
           'file4' with boxes fill pattern 1, \
           'file5' with boxes fill empty
?style boxes 3D
?boxes 3D

`splot with boxes` requires at least 3 columns of input data.  Additional
 input columns may be used to provide information such as box width or
 fill color.

3 columns:  x  y  z
      4 columns:  x  y  z  [x_width or color]
      5 columns:  x  y  z  x_width  color

The last column is used as a color only if the splot command specifies a
 variable color mode.  Examples

splot 'blue_boxes.dat' using 1:2:3 fc "blue"
      splot 'rgb_boxes.dat' using 1:2:3:4 fc rgb variable
      splot 'category_boxes.dat' using 1:2:3:4:5 lc variable

In the first example all boxes are blue and have the width previously set
 by `set boxwidth`.  In the second example the box width is still taken from
 `set boxwidth` because the 4th column is interpreted as a 24-bit RGB color.
 The third example command reads box width from column 4 and interprets the
 value in column 5 as an integer linetype from which the color is derived.

By default boxes have no thickness; they consist of a single rectangle parallel
 to the xz plane at the specified y coordinate.  You can change this to a true
 box with four sides and a top by setting a non-zero extent on y.
 See `set boxdepth`.

3D boxes are processed as pm3d quadrangles rather than as surfaces. Because of
 this the front/back order of drawing is not affected by `set hidden3d`.
 Similarly if you want each box face to have a border you must use
 `set pm3d border` rather than `set style fill border`.  See `set pm3d`.
 For best results use a combination of `set pm3d depthorder base` and
 `set pm3d lighting`.

?plotting styles boxplot
?style boxplot
?with boxplot
?boxplot
 Boxplots are a common way to represent a statistical distribution of values.
 Quartile boundaries are determined such that 1/4 of the points have a value
 equal or less than the first quartile boundary, 1/2 of the points have a value
 equal or less than the second quartile (median) value, etc.  A box is drawn
 around the region between the first and third quartiles, with a horizontal line
 at the median value.  Whiskers extend from the box to user-specified limits.
 Points that lie outside these limits are drawn individually.

Examples

# Place a boxplot at x coordinate 1.0 representing the y values in column 5
     plot 'data' using (1.0):5

# Same plot but suppress outliers and force the width of the boxplot to 0.3
     set style boxplot nooutliers
     plot 'data' using (1.0):5:(0.3)

By default only one boxplot is produced that represents all y values from the
 second column of the using specification. However, an additional (fourth)
 column can be added to the specification. If present, the values of that
 column will be interpreted as the discrete levels of a factor variable.
 As many boxplots will be drawn as there are levels in the factor variable.
 The separation between these boxplots is 1.0 by default, but it can be changed
 by `set style boxplot separation`. By default, the value of the factor variable
 is shown as a tic label below (or above) each boxplot.

Example

# Suppose that column 2 of 'data' contains either "control" or "treatment"
     # The following example produces two boxplots, one for each level of the
     # factor
     plot 'data' using (1.0):5:(0):2

The default width of the box can be set via `set boxwidth <width>` or may be
 specified as an optional 3rd column in the `using` clause of the plot command.
 The first and third columns (x coordinate and width) are normally provided as
 constants rather than as data columns.

By default the whiskers extend from the ends of the box to the most distant
 point whose y value lies within 1.5 times the interquartile range. By default
 outliers are drawn as circles (point type 7).  The width of the bars at the
 end of the whiskers may be controlled using `set bars` or `set errorbars`.

These default properties may be changed using the `set style boxplot` command.
 See `set style boxplot`, `bars`, `boxwidth`, `fillstyle`, `candlesticks`.

?plotting styles boxxyerror
?style boxxyerror
?with boxxyerror
?boxxyerror
 The `boxxyerror` plot style is only relevant to 2D data plotting.
 It is similar to the `xyerrorbars` style except that it draws rectangular areas
 rather than crosses.  It uses either 4 or 6 basic columns of input data.
 Additional input columns may be used to provide information such as
 variable line or fill color (see `rgbcolor variable`).

4 columns:  x  y  xdelta  ydelta
      6 columns:  x  y  xlow  xhigh  ylow  yhigh

The box width and height are determined from the x and y errors in the same
 way as they are for the `xyerrorbars` style---either from xlow to xhigh and
 from ylow to yhigh, or from x-xdelta to x+xdelta and from y-ydelta to
 y+ydelta, depending on how many data columns are provided.

The 6 column form of the command provides a convenient way to plot rectangles
 with arbitrary x and y bounds.

An additional (5th or 7th) input column may be used to provide variable
 (per-datapoint) color information (see `linecolor` and `rgbcolor variable`).

The interior of the boxes is drawn according to the current fillstyle.
 See `set style fill` and `boxes` for details.  Alternatively a new fillstyle
 may be specified in the plot command.
?plotting styles candlesticks
?style candlesticks
?with candlesticks
?candlesticks
 The `candlesticks` style can be used for 2D data plotting of financial
 data or for generating box-and-whisker plots of statistical data.
 The symbol is a rectangular box, centered horizontally at the x
 coordinate and limited vertically by the opening and closing prices.  A
 vertical line segment at the x coordinate extends up from the top of the
 rectangle to the high price and another down to the low.  The vertical line
 will be unchanged if the low and high prices are interchanged.

Five columns of basic data are required:

financial data:   date  open  low  high  close
       whisker plot:     x  box_min  whisker_min  whisker_high  box_high

The width of the rectangle can be controlled by the `set boxwidth` command.
 For backwards compatibility with earlier gnuplot versions, when the
 boxwidth parameter has not been set then the width of the candlestick
 rectangle is taken from `set errorbars <width>`.

Alternatively, an explicit width for each box-and-whiskers grouping may be
 specified in an optional 6th column of data.  The width must be given in the
 same units as the x coordinate.

An additional (6th, or 7th if the 6th column is used for width data)
 input column may be used to provide variable (per-datapoint) color
 information (see `linecolor` and `rgbcolor variable`).

By default the vertical line segments have no crossbars at the top and
 bottom. If you want crossbars, which are typically used for box-and-whisker
 plots, then add the keyword `whiskerbars` to the plot command.  By default
 these whiskerbars extend the full horizontal width of the candlestick, but
 you can modify this by specifying a fraction of the full width.

The usual convention for financial data is that the rectangle is empty
 if (open < close) and solid fill if (close < open). This is the behavior you
 will get if the current fillstyle is set to "empty". See `fillstyle`.
 If you set the fillstyle to solid or pattern, then this will be used for
 all boxes independent of open and close values.
 See also `set errorbars` and `financebars`.  See also the
 candlestick
 and
 finance
 demos.

Note: To place additional symbols, such as the median value, on a
 box-and-whisker plot requires additional plot commands as in this example:

# Data columns:X Min 1stQuartile Median 3rdQuartile Max
   set errorbars 4.0
   set style fill empty
   plot 'stat.dat' using 1:3:2:6:5 with candlesticks title 'Quartiles', \
        ''         using 1:4:4:4:4 with candlesticks lt -1 notitle

# Plot with crossbars on the whiskers, crossbars are 50% of full width
   plot 'stat.dat' using 1:3:2:6:5 with candlesticks whiskerbars 0.5

See `set boxwidth`, `set errorbars`, `set style fill`, and `boxplot`.
?plotting styles circles
?style circles
?with circles
?circles
 The `circles` style plots a circle with an explicit radius at each data point.
 The radius is always interpreted in the units of the plot's horizontal axis
 (x or x2).  The scale on y and the aspect ratio of the plot are both ignored.
 If the radius is not given in a separate column for each point it is taken from
 `set style circle`.  In this case the radius may use graph or screen coordinates.

Many combinations of per-point and previously set properties are possible.
 For 2D plots these include

using x:y
     using x:y:radius
     using x:y:color
     using x:y:radius:color
     using x:y:radius:arc_begin:arc_end
     using x:y:radius:arc_begin:arc_end:color

By default a full circle will be drawn.  It is possible to instead plot arc
 segments by specifying a start and end angle (in degrees) in columns 4 and 5.

A per-circle color may be provided in the last column of the using specifier.
 In this case the plot command must include a corresponding variable color
 term such as `lc variable` or `fillcolor rgb variable`.

For 3D plots the using specifier must contain

splot DATA using x:y:z:radius:color

where the variable color column is options.
 See `set style circle` and `set style fill`.

Examples:

# draws circles whose area is proportional to the value in column 3
     set style fill transparent solid 0.2 noborder
     plot 'data' using 1:2:(sqrt($3)) with circles, \
          'data' using 1:2 with linespoints

# draws Pac-men instead of circles
     plot 'data' using 1:2:(10):(40):(320) with circles

# draw a pie chart with inline data
     set xrange [-15:15]
     set style fill transparent solid 0.9 noborder
     plot '-' using 1:2:3:4:5:6 with circles lc var
     0    0    5    0    30    1
     0    0    5   30    70    2
     0    0    5   70   120    3
     0    0    5  120   230    4
     0    0    5  230   360    5
     e

The result is similar to using a `points` plot with variable size points and
 pointstyle 7, except that the circles will scale with the x axis range.
 See also `set object circle` and `fillstyle`.
?plotting styles ellipses
?style ellipses
?with ellipses
?ellipses
 The `ellipses` style plots an ellipse at each data point.  This style is
 only relevant for 2D plotting.  Each ellipse is described in terms of its
 center, major and minor diameters, and the angle between its major diameter
 and the x axis.

2 columns: x y
      3 columns: x y major_diam
      4 columns: x y major_diam minor_diam
      5 columns: x y major_diam minor_diam angle

If only two input columns are present, they are taken as the coordinates of
 the centers, and the ellipses will be drawn with the default extent
 (see `set style ellipse`).  The orientation of the ellipse, which is
 defined as the angle between the major diameter and the plot's x axis,
 is taken from the default ellipse style (see `set style ellipse`).
 If three input columns are provided, the third column is used for both
 diameters.  The orientation angle defaults to zero.
 If four columns are present, they are interpreted as x, y, major diameter,
 minor diameter.  Note that these are diameters, not radii.
 An optional 5th column may specify the orientation angle in degrees.
 The ellipses will also be drawn with their default extent if either of the
 supplied diameters in the 3-4-5 column form is negative.

In all of the above cases, optional variable color data may be given in an
 additional last (3th, 4th, 5th or 6th) column. See `colorspec`.

By default, the major diameter is interpreted in the units of the plot's
 horizontal axis (x or x2) while the minor diameter in that of the vertical
 (y or y2).  If the x and y axis scales are not equal, the major/minor diameter
 ratio will no longer be correct after rotation.
 This can be changed with the `units` keyword, however.

There are three alternatives:
 if `units xy` is included in the plot specification, the axes will be scaled
 as described above. `units xx` ensures that both diameters are interpreted
 in units of the x axis, while `units yy` means that both diameters are
 interpreted in units of the y axis. In the latter two cases the ellipses
 will have the correct aspect ratio, even if the plot is resized.
 If `units` is omitted from the plot command, the setting from
 `set style ellipse` will be used.

Example (draws ellipses, cycling through the available line types):

plot 'data' using 1:2:3:4:(0):0 with ellipses

See also `set object ellipse`, `set style ellipse` and `fillstyle`.

?plotting styles dots
?style dots
?with dots
?dots
 The `dots` style plots a tiny dot at each point; this is useful for scatter
 plots with many points.  Either 1 or 2 columns of input data are required in
 2D.  Three columns are required in 3D.

For some terminals (post, pdf) the size of the dot can be controlled by
 changing the linewidth.

1 column    y         # x is row number
      2 columns:  x  y
      3 columns:  x  y  z   # 3D only (splot)

?plotting styles filledcurves
?style filledcurves
?with filledcurves
?filledcurves
 The `filledcurves` style is only used for 2D plotting. It has three variants.
 The first two variants require either a single function or two columns (x,y)
 of input data, and may be further modified by the options listed below.

Syntax:

plot ... with filledcurves [option]

where the option can be one of the following

[closed | {above | below}
     {x1 | x2 | y | r}[=<a>] | xy=<x>,<y>]

The first variant, `closed`, treats the curve itself as a closed polygon.
 This is the default if there are two columns of input data.

The second variant is to fill the area between the curve and a given axis,
 a horizontal or vertical line, or a point.

filledcurves closed   ... just filled closed curve,
     filledcurves x1       ... x1 axis,
     filledcurves x2       ... x2 axis, etc for y1 and y2 axes,
     filledcurves y=42     ... line at y=42, i.e. parallel to x axis,
     filledcurves xy=10,20 ... point 10,20 of x1,y1 axes (arc-like shape).
     filledcurves above r=1.5  the area of a polar plot outside radius 1.5

The third variant fills the area between two curves sampled at the same set of
 x coordinates.  It requires three columns of input data (x, y1, y2).
 This is the default if there are three or more columns of input data.
 If you have a y value in column 2 and an associated error value in column 3
 the area of uncertainty can be represented by shading.
 See also the similar 3D plot style `zerrorfill`.

3 columns:  x  y  yerror

plot $DAT using 1:($2-$3):($2+$3) with filledcurves, \
          $DAT using 1:2 smooth mcs with lines

The `above` and `below` options apply both to commands of the form
     ... filledcurves above {x1|x2|y|r}=<val>
 and to commands of the form
     ... using 1:2:3 with filledcurves below
 In either case the option limits the filled area to one side of the bounding
 line or curve.

Notes: Not all terminal types support this plotting mode.
        The x= and y= keywords are ignored for 3 columns data plots

Zooming a filled curve drawn from a datafile may produce empty or incorrect
 areas because gnuplot is clipping points and lines, and not areas.

If the values <x>, <y>, or <a> are outside the drawing boundary they are
 moved to the graph boundary. Then the actual fill area in the case
 of option xy=<x>,<y> will depend on xrange and yrange.
?filledcurves border
 Plotting `with filledcurves` can be further customized by giving a fillstyle
 (solid/transparent/pattern) or a fillcolor.  If no fillstyle (`fs`)
 is given in the plot command then the current default fill style is used.
 See `set style fill`.  If no fillcolor (`fc`) is given in the plot command,
 the usual linetype color sequence is followed.

The {{no}border} property of the fillstyle is honored by filledcurves mode
 `closed`, the default.  It is ignored by all other filledcurves modes.
 Example:
      plot 'data' with filledcurves fc "cyan" fs solid 0.5 border lc "blue"
?plotting styles financebars
?style financebars
?with financebars
?financebars
 The `financebars` style is only relevant for 2D data plotting of financial
 data.  It requires 1 x coordinate (usually a date) and 4 y values (prices).

5 columns:   date  open  low  high  close

An additional (6th) input column may be used to provide variable
 (per-record) color information (see `linecolor` and `rgbcolor variable`).

The symbol is a vertical line segment, located horizontally at the x
 coordinate and limited vertically by the high and low prices.  A horizontal
 tic on the left marks the opening price and one on the right marks the
 closing price.  The length of these tics may be changed by `set errorbars`.
 The symbol will be unchanged if the high and low prices are interchanged.
 See `set errorbars` and `candlesticks`, and also the
 finance demo.
?plotting styles fsteps
?style fsteps
?with fsteps
?fsteps
 The `fsteps` style is only relevant to 2D plotting.  It connects consecutive
 points with two line segments: the first from (x1,y1) to (x1,y2) and the
 second from (x1,y2) to (x2,y2).  The input column requires are the same as for
 plot styles `lines` and `points`.  The difference between `fsteps` and `steps`
 is that `fsteps` traces first the change in y and then the change in x.
 `steps` traces first the change in x and then the change in y.

See also
 steps demo.
?style fillsteps
?with fillsteps
?fillsteps
 The `fillsteps` style is exactly like `steps` except that the area between
 the curve and y=0 is filled in the current fill style.  See `steps`.
?plotting styles histeps
?style histeps
?with histeps
?histeps
 The `histeps` style is only relevant to 2D plotting.  It is intended for
 plotting histograms.  Y-values are assumed to be centered at the x-values;
 the point at x1 is represented as a horizontal line from ((x0+x1)/2,y1) to
 ((x1+x2)/2,y1).  The lines representing the end points are extended so that
 the step is centered on at x.  Adjacent points are connected by a vertical
 line at their average x, that is, from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).
 The input column requires are the same as for plot styles `lines` and `points`.

If `autoscale` is in effect, it selects the xrange from the data rather than
 the steps, so the end points will appear only half as wide as the others.
 See also
 steps demo.

?style histograms
?with histograms
?set style histogram
?plotting styles histograms
?histograms
 The `histograms` style is only relevant to 2D plotting.  It produces a bar
 chart from a sequence of parallel data columns. Each element of the `plot`
 command must specify a single input data source (e.g. one column of the input
 file), possibly with associated tic values or key titles.
 Four styles of histogram layout are currently supported.

set style histogram clustered {gap <gapsize>}
       set style histogram errorbars {gap <gapsize>} {<linewidth>}
       set style histogram rowstacked
       set style histogram columnstacked
       set style histogram {title font "name,size" tc <colorspec>}

The default style corresponds to `set style histogram clustered gap 2`.
 In this style, each set of parallel data values is collected into a group of
 boxes clustered at the x-axis coordinate corresponding to their sequential
 position (row #) in the selected datafile columns.  Thus if <n> datacolumns are
 selected, the first cluster is centered about x=1, and contains <n> boxes whose
 heights are taken from the first entry in the corresponding <n> data columns.
 This is followed by a gap and then a second cluster of boxes centered about x=2
 corresponding to the second entry in the respective data columns, and so on.
 The default gap width of 2 indicates that the empty space between clusters is
 equivalent to the width of 2 boxes.  All boxes derived from any one column
 are given the same fill color and/or pattern (see `set style fill`).

Each cluster of boxes is derived from a single row of the input data file.
 It is common in such input files that the first element of each row is a
 label. Labels from this column may be placed along the x-axis underneath
 the appropriate cluster of boxes with the `xticlabels` option to `using`.

The `errorbars` style is very similar to the `clustered` style, except that it
 requires additional columns of input for each entry. The first column holds
 the height (y value) of that box, exactly as for the `clustered` style.
      2 columns:        y yerr          bar extends from y-yerr to y+err
      3 columns:        y ymin ymax     bar extends from ymin to ymax
 The appearance of the error bars is controlled by the current value of
 `set errorbars` and by the optional <linewidth> specification.

Two styles of stacked histogram are supported, chosen by the command
 `set style histogram {rowstacked|columnstacked}`.  In these styles the data
 values from the selected columns are collected into stacks of boxes.
 Positive values stack upwards from y=0; negative values stack downwards.
 Mixed positive and negative values will produce both an upward stack and a
 downward stack.  The default stacking mode is `rowstacked`.

The `rowstacked` style places a box resting on the x-axis for each
 data value in the first selected column; the first data value results in
 a box a x=1, the second at x=2, and so on.  Boxes corresponding to the
 second and subsequent data columns are layered on top of these, resulting
 in a stack of boxes at x=1 representing the first data value from each
 column, a stack of boxes at x=2 representing the second data value from
 each column, and so on.  All boxes derived from any one column are given the
 same fill color and/or pattern (see `set style fill`).

The `columnstacked` style is similar, except that each stack of boxes is
 built up from a single data column. Each data value from the first specified
 column yields a box in the stack at x=1, each data value from the second
 specified column yields a box in the stack at x=2, and so on.  In this style
 the color of each box is taken from the row number, rather than the column
 number, of the corresponding data field.

Box widths may be modified using the `set boxwidth` command.
 Box fill styles may be set using the `set style fill` command.

Histograms always use the x1 axis, but may use either y1 or y2.
 If a plot contains both histograms and other plot styles, the non-histogram
 plot elements may use either the x1 or the x2 axis.

Examples:
 Suppose that the input file contains data values in columns 2, 4, 6, ...
 and error estimates in columns 3, 5, 7, ...  This example plots the values
 in columns 2 and 4 as a histogram of clustered boxes (the default style).
 Because we use iteration in the plot command, any number of data columns can
 be handled in a single command. See `plot for`.

set boxwidth 0.9 relative
       set style data histograms
       set style histogram cluster
       set style fill solid 1.0 border lt -1
       plot for [COL=2:4:2] 'file.dat' using COL

This will produce a plot with clusters of two boxes (vertical bars) centered
 at each integral value on the x axis.  If the first column of the input file
 contains labels, they may be placed along the x-axis using the variant command

plot for [COL=2:4:2] 'file.dat' using COL:xticlabels(1)

If the file contains both magnitude and range information for each value,
 then error bars can be added to the plot.  The following commands will add
 error bars extending from (y-<error>) to (y+<error>), capped by horizontal bar
 ends drawn the same width as the box itself. The error bars and bar ends are
 drawn with linewidth 2, using the border linetype from the current fill style.

set errorbars fullwidth
       set style fill solid 1 border lt -1
       set style histogram errorbars gap 2 lw 2
       plot for [COL=2:4:2] 'file.dat' using COL:COL+1

This shows how to plot the same data as a rowstacked histogram.  Just to be
 different, this example lists the separate columns explicitly rather than using
 iteration.

set style histogram rowstacked
       plot 'file.dat' using 2, '' using 4:xtic(1)

This will produce a plot in which each vertical bar corresponds to one row of
 data.  Each vertical bar contains a stack of two segments, corresponding in
 height to the values found in columns 2 and 4 of the datafile.
 Finally, the commands

set style histogram columnstacked
       plot 'file.dat' using 2, '' using 4

will produce two vertical stacks, one for each column of data.  The stack at
 x=1 will contain a box for each entry in column 2 of the datafile.  The stack
 at x=2 will contain a box for each parallel entry in column 4 of the datafile.

Because this interchanges gnuplot's usual interpretation of input rows and
 columns, the specification of key titles and x-axis tic labels must also be
 modified accordingly. See the comments given below.

set style histogram columnstacked
       plot '' u 5:key(1)            # uses first column to generate key titles
       plot '' u 5 title columnhead  # uses first row to generate xtic labels

Note that the two examples just given present exactly the same data values,
 but in different formats.
?newhistogram
?histograms newhistogram
?plotting styles histograms newhistogram
 Syntax:

newhistogram {"<title>" {font "name,size"} {tc <colorspec>}}
                   {lt <linetype>} {fs <fillstyle>} {at <x-coord>}

More than one set of histograms can appear in a single plot. In this case you
 can force a gap between them, and a separate label for each set, by using the
 `newhistogram` command.
 For example

set style histogram  cluster
       plot newhistogram "Set A", 'a' using 1, '' using 2, '' using 3, \
            newhistogram "Set B", 'b' using 1, '' using 2, '' using 3

The labels "Set A" and "Set B" will appear beneath the respective sets of
 histograms, under the overall x axis label.

The newhistogram command can also be used to force histogram coloring to
 begin with a specific color (linetype). By default colors will continue to
 increment successively even across histogram boundaries. Here is an example
 using the same coloring for multiple histograms
       plot newhistogram "Set A" lt 4, 'a' using 1, '' using 2, '' using 3, \
            newhistogram "Set B" lt 4, 'b' using 1, '' using 2, '' using 3

Similarly you can force the next histogram to begin with a specified fillstyle.
 If the fillstyle is set to `pattern`, then the pattern used for filling will
 be incremented automatically.

The `at <x-coord>` option sets the x coordinate position of the following
 histogram to <x-coord>. For example

set style histogram cluster
        set style data histogram
        set style fill solid 1.0 border -1
        set xtic 1 offset character 0,0.3
        plot newhistogram "Set A", \
             'file.dat' u 1 t 1, '' u 2 t 2, \
             newhistogram "Set B" at 8, \
             'file.dat' u 2 t 2, '' u 2 t 2

will position the second histogram to start at x=8.
?automated
?histograms automated
?styles histograms automated
?plotting styles histograms automated
 If you want to create a histogram from many columns of data in a single file,
 it is very convenient to use the plot iteration feature.  See `plot for`.
 For example, to create stacked histograms of the data in columns 3 through 8

set style histogram columnstacked
       plot for [i=3:8] "datafile" using i title columnhead
?plotting styles image
?style image
?with image
?image
?rgbimage
?rgbalpha
 The `image`, `rgbimage`, and `rgbalpha` plotting styles all project a
 uniformly sampled grid of data values onto a plane  in either 2D or 3D.
 The input data may be an actual bitmapped image, perhaps converted from a
 standard format such as PNG, or a simple array of numerical values.

This figure illustrates generation of a heat map from an array of scalar values.
 The current palette is used to map each value onto the color assigned to the
 corresponding pixel.
       plot '-' matrix with image
       5 4 3 1 0
       2 2 0 0 1
       0 0 0 1 0
       0 1 2 4 3
       e
       e

Each pixel (data point) of the input 2D image will become a rectangle or
 parallelipiped in the plot. The coordinates of each data point will determine
 the center of the parallelipiped.  That is, an M x N set of data will form an
 image with M x N pixels.  This is different from the pm3d plotting style, where
 an M x N set of data will form a surface of (M-1) x (N-1) elements.  The scan
 directions for a binary image data grid can be further controlled by additional
 keywords. See `binary keywords flipx`, `keywords center`, and `keywords rotate`.

Image data can be scaled to fill a particular rectangle within a 2D plot
 coordinate system by specifying the x and y extent of each pixel.
 See `binary keywords dx` and `dy`. To generate the figure at the right,
 the same input image was placed multiple times, each with a specified dx, dy,
 and origin. The input PNG image of a building is 50x128 pixels.  The tall
 building was drawn by mapping this using `dx=0.5 dy=1.5`.  The short building
 used a mapping `dx=0.5 dy=0.35`.

The `image` style handles input pixels containing a grayscale or color palette
 value. Thus 2D plots (`plot` command) require 3 columns of data (x,y,value),
 while 3D plots (`splot` command) require 4 columns of data (x,y,z,value).

The `rgbimage` style handles input pixels that are described by three separate
 values for the red, green, and blue components.  Thus 5D data (x,y,r,g,b) is
 needed for `plot` and 6D data (x,y,z,r,g,b) for `splot`.  The individual red,
 green, and blue components are assumed to lie in the range [0:255].
 This matches the convention used in PNG and JPEG files (see `binary filetype`).
 However some data files use an alternative convention in which RGB components
 are floating point values in the range [0:1]. To use the `rgbimage` style with
 such data, first use the command `set rgbmax 1.0`.

The `rgbalpha` style handles input pixels that contain alpha channel
 (transparency) information in addition to the red, green, and blue components.
 Thus 6D data (x,y,r,g,b,a) is needed for `plot` and 7D data (x,y,z,r,g,b,a)
 for `splot`.  The r, g, b, and alpha components are assumed to lie in the range
 [0:255].  To plot data for which RGBA components are floating point values in
 the range [0:1], first use the command `set rgbmax 1.0`.

If only a single data column is provided for the color components of either
 rgbimage or rgbalpha plots, it is interpreted as containing 32 bit packed ARGB 
 data using the convention that alpha=0 means opaque and alpha=255 means fully
 transparent. Note that this is backwards from the alpha convention if alpha
 is supplied in a separate column, but matches the ARGB packing convention for
 individual commands to set color. See `colorspec`.
?image transparency
?transparency
?alpha channel
 The `rgbalpha` plotting style assumes that each pixel of input data contains
 an alpha value in the range [0:255].  A pixel with alpha = 0 is purely
 transparent and does not alter the underlying contents of the plot. A pixel
 with alpha = 255 is purely opaque.  All terminal types can handle these two
 extreme cases.  A pixel with 0 < alpha < 255 is partially transparent.
 Terminal types that do not support partial transparency will round this value
 to 0 or 255.
?plotting styles image pixels
?style image pixels
?with image pixels
?image pixels
?pixels
 Some terminals use device- or library-specific optimizations to render image
 data within a rectangular 2D area.  This sometimes produces undesirable output,
 e.g. bad clipping or scaling, missing edges.  The `pixels` keyword tells
 gnuplot to use generic code that renders the image pixel-by-pixel instead.
 This rendering mode is slower and may result in much larger output files, but
 should produce a consistent rendered view on all terminals.
 Example:
       plot 'data' with image pixels

?plotting styles impulses
?style impulses
?with impulses
?impulses
 The `impulses` style displays a vertical line from y=0 to the y value of each
 point (2D) or from z=0 to the z value of each point (3D).  Note that the y or z
 values may be negative.  Data from additional columns can be used to control
 the color of each impulse.  To use this style effectively in 3D plots, it is
 useful to choose thick lines (linewidth > 1). This approximates a 3D bar chart.

1 column:   y
      2 columns:  x  y     # line from [x,0] to [x,y]  (2D)
      3 columns:  x  y  z  # line from [x,y,0] to [x,y,z] (3D)

?plotting styles labels
?style labels
?with labels
?labels
 The `labels` style reads coordinates and text from a data file and places
 the text string at the corresponding 2D or 3D position.  3 or 4 input columns
 of basic data are required.  Additional input columns may be used to provide
 properties that vary point by point such as text rotation angle (keywords
 `rotate variable`) or color (see `textcolor variable`).

3 columns:  x  y  string    # 2D version
      4 columns:  x  y  z  string # 3D version

The font, color, rotation angle and other properties of the printed text
 may be specified as additional command options (see `set label`). The example
 below generates a 2D plot with text labels constructed from the city whose
 name is taken from column 1 of the input file, and whose geographic coordinates
 are in columns 4 and 5. The font size is calculated from the value in column 3,
 in this case the population.

CityName(String,Size) = sprintf("{/=%d %s}", Scale(Size), String)
   plot 'cities.dat' using 5:4:(CityName(stringcolumn(1),$3)) with labels

If we did not want to adjust the font size to a different size for each city
 name, the command would be much simpler:

plot 'cities.dat' using 5:4:1 with labels font "Times,8"

If the labels are marked as `hypertext` then the text only appears if the
 mouse is hovering over the corresponding anchor point.  See `hypertext`.
 In this case you must enable the label's `point` attribute so that there is
 a point to act as the hypertext anchor:

plot 'cities.dat' using 5:4:1 with labels hypertext point pt 7

The `labels` style can also be used in place of the `points` style when the
 set of predefined point symbols is not suitable or not sufficiently flexible.
 For example, here we define a set of chosen single-character symbols and assign
 one of them to each point in a plot based on the value in data column 3:

set encoding utf8
   symbol(z) = "∙□+⊙♠♣♡♢"[int(z):int(z)]
   splot 'file' using 1:2:(symbol($3)) with labels

This example shows use of labels with variable rotation angle in column 4 and
 textcolor ("tc") in column 5.  Note that variable color is always taken from
 the last column in the `using` specifier.

plot $Data using 1:2:3:4:5 with labels tc variable rotate variable
?plotting styles lines
?style lines
?with lines
?lines
 The `lines` style connects adjacent points with straight line segments.
 It may be used in either 2D or 3D plots. The basic form requires 1, 2, or 3
 columns of input data.
 Additional input columns may be used to provide information such as
 variable line color (see `rgbcolor variable`).

2D form (no "using" spec)
      1 column:   y       # implicit x from row number
      2 columns:  x  y
 3D form (no "using" spec)
      1 column:   z       # implicit x from row, y from index
      3 columns:  x  y  z

See also `linetype`, `linewidth`, and `linestyle`.
?plotting styles linespoints
?style linespoints
?with linespoints
?style lp
?with lp
?linespoints
?lp
?pointinterval
?pointnumber
 The `linespoints` style (short form `lp`) connects adjacent points with
 straight line segments and then goes back to draw a small symbol at each point.
 Points are drawn with the default size determined by `set pointsize` unless a
 specific point size is given in the plot command or a variable point size is
 provided in an additional column of input data.  Additional input columns may
 also be used to provide information such as variable line color.
 See `lines` and `points`.

Two keywords control whether or not every point in the plot is marked with a
 symbol, `pointinterval` (short form `pi`) and `pointnumber` (short form `pn`).

`pi N` or `pi -N` tells gnuplot to only place a symbol on every Nth point.
 A negative value for N will erase the portion of line segment that passes
 underneath the symbol. The size of the erased portion is controlled by
 `set pointintervalbox`.

`pn N` or `pn -N` tells gnuplot to label only N of the data points, evenly
 spaced over the data set.  As with `pi`, a negative value for N will erase the
 portion of line segment that passes underneath the symbol.

?plotting styles parallelaxes
?plot with parallelaxes
?with parallelaxes
?parallelaxes
?parallel
 Parallel axis plots can highlight correlation in a multidimensional data set.
 Individual columns of input data are each associated with a separately scaled
 vertical axis.  If all columns are drawn from a single file then each line on
 the plot represents values from a single row of data in that file.
 It is common to use some discrete categorization to assign line colors,
 allowing visual exploration of the correlation between this categorization and
 the axis dimensions.

Syntax:

set style data parallelaxes
     plot $DATA using col1{:varcol1} {at <xpos>} {<line properties}, \
          $DATA using col2, ...

CHANGE: Version 5.4 of gnuplot introduces a change in the syntax for plot style
 parallelaxes.  The revised syntax allows an unlimited number of parallel axes.

gnuplot 5.2:   plot $DATA using 1:2:3:4:5 with parallelaxes
      gnuplot 5.4:   plot for [col=1:5] $DATA using col with parallelaxes

The new syntax also allows explicit placement of the parallel vertical axes
 along the x axis as in the example below.  If no explicit x coordinate is
 provide axis N will be placed at x=N.

array xpos[5] = [1, 5, 6, 7, 11, 12]
      plot for [col=1:5] $DATA using col with parallelaxes at xpos[col]

By default gnuplot will automatically determine the range and scale of the
 individual axes from the input data, but the usual `set axis range` commands
 can be used to customize this.  See `set paxis`.
 Polar plots are generated by changing the current coordinate system to
 polar before issuing a plot command.  The option `set polar` tells gnuplot to
 interpret input 2D coordinates as <angle>,<radius> rather than <x>,<y>.
 Many, but not all, of the 2D plotting styles work in polar mode.
 The figure shows a combination of plot styles `lines` and `filledcurves`.
 See `set polar`, `set rrange`, `set size square`, `set theta`, `set ttics`.
?plotting styles points
?style points
?with points
?points
?point type
?pointtype
 The `points` style displays a small symbol at each point. The command `set
 pointsize` may be used to change the default size of all points. The point type
 defaults to that of the linetype. See `linetype`.  If no `using` spec is found
 in the plot command, input data columns are interpreted implicitly in the order
      x y pointsize pointtype color
 Any columns beyond the first two (x and y) are optional; they correspond to
 additional plot properties `pointsize variable`, `pointtype variable`, etc.

The first 8 point types are shared by all terminals. Individual terminals may
 provide a much larger number of distinct point types. Use the `test` command
 to show what is provided by the current terminal settings.

Alternatively any single printable character may be given instead of a
 numerical point type, as in the example below.  You may use any unicode
 character as the pointtype (assumes utf8 support). See `escape sequences`.
 Longer strings may be plotted using plot style `labels` rather than `points`.

plot f(x) with points pt "#"
      plot d(x) with points pt "\U+2299"

?points variable
?with points variable
?variable
?pointtype variable
?pointsize variable
 When using the keywords `pointtype`, `pointsize`, or `linecolor` in a plot
 command, the additional keyword `variable` may be given instead of a number.
 In this case the corresponding properties of each point are assigned by
 additional columns of input data. Variable pointsize is always taken from the
 first additional column provided in a `using` spec.  Variable color is always
 taken from the last additional column. See `colorspec`. If all three properties
 are specified for each point, the order of input data columns is thus

plot DATA using x:y:pointsize:pointtype:color \
           with points lc variable pt variable ps variable

Note: for information on user-defined program variables, see `variables`.
?plotting styles polygons
?style polygons
?with polygons
?polygons
      splot DATA {using x:y:z} with polygons
            {fillstyle <fillstyle spec>}
            {fillcolor <colorspec>}
 `splot with polygons` uses pm3d to render individual triangles, quadrangles,
 and larger polygons in 3D.  These may be facets of a 3D surface or isolated
 shapes. The code assumes that the vertices lie in a plane.
 Vertices defining individual polygons are read from successive records of the
 input file.  A blank line separates one polygon from the next.

The fill style and color may be specified in the splot command, otherwise the
 global fillstyle from `set style fill` is used.  Due to limitations in the
 pm3d code, a single border line style from `set pm3d border` is applied to all
 polygons.  This restriction may be removed in a later gnuplot version.
 
 pm3d sort order and lighting are applied to the faces. It is probably always
 desirable to use `set pm3d depthsort`.

set xyplane at 0
      set view equal xyz
      unset border
      unset tics
      set pm3d depth
      set pm3d border lc "black" lw 1.5
      splot 'icosahedron.dat' with polygons \
            fs transparent solid 0.8 fc bgnd
?plotting styles spiderplot
?with spiderplot
?spiderplot
?radar chart
 Spider plots are essentially parallel axis plots in which the axes are arranged
 radially rather than vertically. Such plots are sometimes called `rader charts`.
 In gnuplot this requires working within a coordinate system established by the
 command `set spiderplot`, analogous to `set polar` except that the angular
 coordinate is determined implicitly by the parallel axis number. The appearance,
 labelling, and tic placement of the axes is controlled by `set paxis`.
 Further style choices are controlled using `set style spiderplot`, `set grid`,
 and the individual components of the plot command.

Because each spider plot corresponds to a row of data rather than a column,
 it would make no sense to generate key entry titles in the normal way.
 Instead, if a plot component contains a title the text is used to label the
 corresponding axis. This overrides any previous `set paxis n label "Foo"`.
 To place a title in the key, you can either use a separate `keyentry` command
 or extract text from a column in the input file with the `key(column)`
 using specifier.  See `keyentry`, `using key`.
 
 In this figure a spiderplot with 5 axes is used to compare multiple entities
 that are each characterized by five scores.  Each line (row) in $DATA
 generates a new polygon on the plot.

set spiderplot
      set style spiderplot fs transparent solid 0.2 border
      set for [p=1:5] paxis p range [0:100]
      set for [p=2:5] paxis p tics format ""
      set             paxis 1 tics font ",9"
      set for [p=1:5] paxis p label sprintf("Score %d",p)
      set grid spiderplot
      plot for [i=1:5] $DATA using i:key(1)

?newspiderplot
?spiderplot newspiderplot
 Normally the sequential elements of a plot command `with spiderplot` each
 correspond to one vertex of a single polygon.  In order to describe multiple
 polygons in the same plot command, they must be separated by `newspiderplot`.
 Example:
      # One polygon with 10 vertices
      plot for [i=1:5] 'A' using i, for [j=1:5] 'B' using j
      # Two polygons with 5 vertices
      plot for [i=1:5] 'A' using i, newspiderplot, for [j=1:5] 'B' using j

?plotting styles steps
?style steps
?with steps
?steps
 The `steps` style is only relevant to 2D plotting.  It connects consecutive
 points with two line segments: the first from (x1,y1) to (x2,y1) and the
 second from (x2,y1) to (x2,y2).  The input column requires are the same as for
 plot styles `lines` and `points`.  The difference between `fsteps` and `steps`
 is that `fsteps` traces first the change in y and then the change in x.
 `steps` traces first the change in x and then the change in y.  To fill the
 area between the curve and the baseline at y=0, use `fillsteps`.
 See also
 steps demo.

?plotting styles rgbalpha
?style rgbalpha
?with rgbalpha
 See `image`.
?plotting styles rgbimage
?style rgbimage
?with rgbimage
 See `image`.
?plotting styles vectors
?style vectors
?with vectors
?vectors
 The 2D `vectors` style draws a vector from (x,y) to (x+xdelta,y+ydelta).
 The 3D `vectors` style is similar, but requires six columns of basic data.
 In both cases, an additional input column (5th in 2D, 7th in 3D) may be used
 to provide variable (per-datapoint) color information.
 (see `linecolor` and `rgbcolor variable`).
 A small arrowhead is drawn at the end of each vector.

4 columns:  x  y  xdelta  ydelta
      6 columns:  x  y  z  xdelta  ydelta  zdelta

The keywords "with vectors" may be followed by an inline arrow style
 specifications, a reference to a predefined arrow style, or a request to read
 the index of the desired arrow style for each vector from a separate column.
 Note: If you choose "arrowstyle variable" it will fill in all arrow properties
 at the time the corresponding vector is drawn; you cannot mix this keyword with
 other line or arrow style qualifiers in the plot command.

plot ... with vectors filled heads
      plot ... with vectors arrowstyle 3
      plot ... using 1:2:3:4:5 with vectors arrowstyle variable

Example:
       plot 'file.dat' using 1:2:3:4 with vectors head filled lt 2
       splot 'file.dat' using 1:2:3:(1):(1):(1) with vectors filled head lw 2

splot with vectors is supported only for `set mapping cartesian`.
 `set clip one` and `set clip two` affect vectors drawn in 2D.
 See `set clip` and `arrowstyle`.

See also the 2D plot style `with arrows` that is identical to `with vectors`
 except that each arrow is specified using x:y:length:angle.
?plotting styles xerrorbars
?style xerrorbars
?with xerrorbars
?xerrorbars
 The `xerrorbars` style is only relevant to 2D data plots.  `xerrorbars` is
 like `points`, except that a horizontal error bar is also drawn.  At each point
 (x,y), a line is drawn from (xlow,y) to (xhigh,y) or from (x-xdelta,y) to
 (x+xdelta,y), depending on how many data columns are provided.  The appearance
 of the tic mark at the ends of the bar is controlled by `set errorbars`.
 The basic style requires either 3 or 4 columns:

3 columns:  x  y  xdelta
      4 columns:  x  y  xlow  xhigh

An additional input column (4th or 5th) may be used to provide information
 such as variable point color.

?plotting styles xyerrorbars
?style xyerrorbars
?with xyerrorbars
?xyerrorbars
 The `xyerrorbars` style is only relevant to 2D data plots.  `xyerrorbars` is
 like `points`, except that horizontal and vertical error bars are also drawn.
 At each point (x,y), lines are drawn from (x,y-ydelta) to (x,y+ydelta) and
 from (x-xdelta,y) to (x+xdelta,y) or from (x,ylow) to (x,yhigh) and from
 (xlow,y) to (xhigh,y), depending upon the number of data columns provided.
 The appearance of the tic mark at the ends of the bar is controlled by
 `set errorbars`.  Either 4 or 6 input columns are required.

4 columns:  x  y  xdelta  ydelta
      6 columns:  x  y  xlow  xhigh  ylow  yhigh

If data are provided in an unsupported mixed form, the `using` filter on the
 `plot` command should be used to set up the appropriate form.  For example,
 if the data are of the form (x,y,xdelta,ylow,yhigh), then you can use

plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars

An additional input column (5th or 7th) may be used to provide variable
 (per-datapoint) color information.

?plotting styles yerrorbars
?plotting styles errorbars
?style yerrorbars
?with yerrorbars
?style errorbars
?with errorbars
?yerrorbars
 The `yerrorbars` (or `errorbars`) style is only relevant to 2D data plots.
 `yerrorbars` is like `points`, except that a vertical error bar is also drawn.
 At each point (x,y), a line is drawn from (x,y-ydelta) to (x,y+ydelta) or
 from (x,ylow) to (x,yhigh), depending on how many data columns are provided.
 The appearance of the tic mark at the ends of the bar is controlled by
 `set errorbars`.

2 columns:  [implicit x] y ydelta
      3 columns:  x  y  ydelta
      4 columns:  x  y  ylow  yhigh

An additional input column (4th or 5th) may be used to provide information
 such as variable point color.

See also
 errorbar demo.
?plotting styles xerrorlines
?style xerrorlines
?with xerrorlines
?xerrorlines
 The `xerrorlines` style is only relevant to 2D data plots.
 `xerrorlines` is like `linespoints`, except that a horizontal error line is
 also drawn. At each point (x,y), a line is drawn from (xlow,y) to (xhigh,y)
 or from (x-xdelta,y) to (x+xdelta,y), depending on how many data columns are
 provided.  The appearance of the tic mark at the ends of the bar is controlled
 by `set errorbars`.  The basic style requires either 3 or 4 columns:

3 columns:  x  y  xdelta
      4 columns:  x  y  xlow  xhigh

An additional input column (4th or 5th) may be used to provide information
 such as variable point color.

?plotting styles xyerrorlines
?style xyerrorlines
?with xyerrorlines
?xyerrorlines
 The `xyerrorlines` style is only relevant to 2D data plots.
 `xyerrorlines` is like `linespoints`, except that horizontal and vertical
 error bars are also drawn. At each point (x,y), lines are drawn from
 (x,y-ydelta) to (x,y+ydelta) and from (x-xdelta,y) to (x+xdelta,y) or from
 (x,ylow) to (x,yhigh) and from (xlow,y) to (xhigh,y), depending upon the
 number of data columns provided.  The appearance of the tic mark at the ends
 of the bar is controlled by `set errorbars`.
 Either 4 or 6 input columns are required.

4 columns:  x  y  xdelta  ydelta
      6 columns:  x  y  xlow  xhigh  ylow  yhigh

plot 'data' using 1:2:($1-$3):($1+$3):4:5 with xyerrorlines

An additional input column (5th or 7th) may be used to provide variable
 (per-datapoint) color information.

?plotting styles yerrorlines
?plotting styles errorlines
?style yerrorlines
?with yerrorlines
?style errorlines
?with errorlines
?yerrorlines
 The `yerrorlines` (or `errorlines`) style is only relevant to 2D data
 plots. `yerrorlines` is like `linespoints`, except that a vertical error line
 is also drawn. At each point (x,y), a line is drawn from (x,y-ydelta) to
 (x,y+ydelta) or from (x,ylow) to (x,yhigh), depending on how many data columns
 are provided.  The appearance of the tic mark at the ends of the bar is
 controlled by `set errorbars`.  Either 3 or 4 input columns are required.

3 columns:  x  y  ydelta
      4 columns:  x  y  ylow  yhigh

An additional input column (4th or 5th) may be used to provide information
 such as variable point color.

See also
 errorbar demo.
?3D plots
?plotting styles 3D plots
 3D plots are generated using the command `splot` rather than `plot`.
 Many of the 2D plot styles (points, images, impulse, labels, vectors) can also
 be used in 3D by providing an extra column of data containing z coordinate.
 Some plot types (pm3d coloring, surfaces, contours) must be generated using the
 `splot` command even if only a 2D projection is wanted.
?surface plots
 The styles `splot with lines` and `splot with surface` both generate a surface
 made from a grid of lines.  Solid surfaces can be generated using the style
 `splot with pm3d`.  Usually the surface is displayed at some convenient viewing
 angle, such that it clearly represents a 3D surface.  See `set view`.
 In this case the X, Y, and Z axes are all visible in the plot.
 The illusion of 3D is enhanced by choosing hidden line removal. See `hidden3d`.
 The `splot` command can also calculate and draw contour lines corresponding
 to constant Z values. These contour lines may be drawn onto the surface
 itself, or projected onto the XY plane. See `set contour`.
?2D projection (set view map)
 An important special case of the `splot` command is to map the Z coordinate
 onto a 2D surface by projecting the plot along the Z axis onto the xy plane.
 See `set view map`.  This plot mode is useful for contour plots and heat maps.
 This figure shows contours plotted once with plot style `lines` and once with
 style `labels`.
?PM3D PLOTS
 3D surfaces can also be drawn using solid pm3d quadrangles rather than 
 lines. In this case there is no hidden surface removal, but if the component
 facets are drawn back-to-front then a similar effect is achieved.
 See `set pm3d depthorder`. While pm3d surfaces are by default colored using a
 smooth color palette (see `set palette`), it is also possible to specify a
 solid color surface or to specify distinct solid colors for the top and bottom
 surfaces as in the figure shown here.  See `pm3d fillcolor`.
 Unlike the line-trimming in hidden3d mode, pm3d surfaces can be smoothly
 clipped to the current zrange.  See `set pm3d clipping`.

?fenceplots
 Fence plots combine several 2D plots by aligning their Y coordinates and
 separating them from each other by a displacement along X. Filling the area
 between a base value and each plot's series of Z values enhances the visual
 impact of the alignment on Y and comparison on Z. There are several ways
 such plots can be created in gnuplot. The simplest is to use the 5 column
 variant of the `zerrorfill` style. Suppose there are separate curves z = Fi(y)
 indexed by i. A fence plot is generated by `splot with zerrorfill` using
 input columns
      i y z_base z_base Fi(y)

?plotting styles isosurface
?style isosurface
?with isosurface
?isosurface
 This 3D plot style requires a populated voxel grid (see `set vgrid`, `vfill`).
 Linear interpolation of voxel grid values is used to estimate fractional grid
 coordinates corresponding to the requested isolevel.  These points are then 
 used to generate a tessellated surface.  The facets making up the surface are
 rendered as pm3d polygons, so the surface coloring, transparency, and border
 properties are controlled by `set pm3d`.  In general the surface is easier to
 interpret visually if facets are given a thin border that is darker than the
 fill color.  By default the tessellation uses a mixture of quadrangles and
 triangles.  To use triangle only, see `set isosurface`.
 Example:
      set style fill solid 0.3
      set pm3d depthorder border lc "blue" lw 0.2
      splot $helix with isosurface level 10 fc "cyan"

?plotting styles zerrorfill
?style zerrorfill
?with zerrorfill
?zerrorfill
 Syntax:

splot DATA using 1:2:3:4[:5] with zerrorfill {fc|fillcolor <colorspec>}
                 {lt|linetype <n>} {<line properties>}

The `zerrorfill` plot style is similar to one variant of the 2D plot style
 `filledcurves`.  It fills the area between two functions or data lines that
 are sampled at the same x and y points.  It requires 4 or 5 input columns:

4 columns:  x  y  z  zdelta
      5 columns:  x  y  z  zlow  zhigh

The area between zlow and zhigh is filled and then a line is drawn through the
 z values. By default both the line and the fill area use the same color, but
 you can change this in the splot command.  The fill area properties are also
 affected by the global fill style; see `set style fill`.

If there are multiple curves in the splot command each new curve may occlude
 all previous curves.  To get proper depth sorting so that curves can only be
 occluded by curves closer to the viewer, use `set pm3d depthorder base`.
 Unfortunately this causes all the filled areas to be drawn after all of the
 corresponding lines of z values.  In order to see both the lines and the
 depth-sorted fill areas you probably will need to make the fill areas
 partially transparent or use pattern fill rather than solid fill.

The fill area in the first two examples below is the same.

splot 'data' using 1:2:3:4 with zerrorfill fillcolor "grey" lt black
      splot 'data' using 1:2:3:($3-$4):($3+$4) with zerrorfill
      splot '+' using 1:(const):(func1($1)):(func2($1)) with zerrorfill
      splot for [k=1:5] datafile[k] with zerrorfill lt black fc lt (k+1)

This plot style can also be used to create fence plots. See `fenceplots`.

?commands
 This section lists the commands acceptable to `gnuplot` in alphabetical
 order.  Printed versions of this document contain all commands; the text
 available interactively may not be complete.  Indeed, on some systems there may
 be no commands at all listed under this heading.

Note that in most cases unambiguous abbreviations for command names and their
 options are permissible, i.e., "`p f(x) w li`" instead of "`plot f(x) with
 lines`".

In the syntax descriptions, braces ({}) denote optional arguments and a
 vertical bar (|) separates mutually exclusive choices.
?commands break
?break
 The `break` command is only meaningful inside the bracketed iteration clause
 of a `do` or `while` statement.  It causes the remaining statements inside the
 bracketed clause to be skipped and iteration is terminated.  Execution resumes
 at the statement following the closing bracket.  See also `continue`.
?commands cd
?cd
 The `cd` command changes the working directory.

Syntax:
       cd '<directory-name>'

The directory name must be enclosed in quotes.

Examples:
       cd 'subdir'
       cd ".."

It is recommended that Windows users use single-quotes, because backslash [\]
 has special significance inside double-quotes and has to be escaped.
 For example,
       cd "c:\newdata"
 fails, but
       cd 'c:\newdata'
       cd "c:\\newdata"
 work as expected.
?commands call
?call
 The `call` command is identical to the `load` command with one exception:
 the name of the file being loaded may be followed by up to nine parameters.

call "inputfile" <param-1> <param-2> <param-3> ... <param-9>

Previous versions of gnuplot performed macro-like substitution of the special
 tokens $0, $1, ... $9 with the literal contents of these parameters.
 This mechanism is now deprecated (see `call old-style`).

Gnuplot now provides a set of string variables ARG0, ARG1, ..., ARG9 and an
 integer variable ARGC. When a `call` command is executed ARG0 is set to the
 name of the input file, ARGC is set to the number of parameters present, and
 ARG1 to ARG9 are loaded from the parameters that follow it on the command line.
 Any existing contents of the ARG variables are saved and restored across a
 `call` command.

Because the parameters ARG1 ... ARG9 are stored in ordinary string variables
 they may be dereferenced by macro expansion (analogous to the older deprecated
 syntax).  However in many cases it is more natural to use them as you would any
 other variable.

In parallel to the string parameters ARG1 ... ARG9, the passed parameters are
 stored in an array ARGV[9].  See `argv`.

?argv
?ARGV
?call argv
?call ARGV
 When a gnuplot script is entered via the `call` command any parameters passed
 by the caller are available via two mechanisms.  Each parameter is stored as a
 string in variables ARG1, ARG2, ... ARG9.  Each parameter is also stored as one
 element of the array ARGV[9]. Numerical values are stored as complex variables.
 All other values are stored as strings.  Thus after a call

call 'routine_1.gp'  1 pi "title"

The three arguments are available inside routine_1.gp as follows

ARG1 = "1"         ARGV[1] = 1.0
      ARG2 = "3.14159"   ARGV[2] = 3.14159265358979...
      ARG3 = "title"     ARGV[3] = "title"

In this example ARGV[1] and ARGV[2] have the full precision of a floating point
 variable.  ARG2 lost precision in being stored as a string using format "%g".
?call example
?commands call example
      Call site
          MYFILE = "script1.gp"
          FUNC = "sin(x)"
          call MYFILE FUNC 1.23 "This is a plot title"
      Upon entry to the called script
          ARG0 holds "script1.gp"
          ARG1 holds the string "sin(x)"
          ARG2 holds the string "1.23"
          ARG3 holds the string "This is a plot title"
          ARGC is 3
      The script itself can now execute
          plot @ARG1 with lines title ARG3
          print ARG2 * 4.56, @ARG2 * 4.56
          print "This plot produced by script ", ARG0

Notice that because ARG1 is a string it must be dereferenced as a macro,
 but ARG2 may be dereferenced either as a macro (yielding a numerical constant)
 or a variable (yielding that same numerical value after auto-promotion of the
 string "1.23" to a real).

The same result could be obtained directly from a shell script by invoking
 gnuplot with the `-c` command line option:

gnuplot -persist -c "script1.gp" "sin(x)" 1.23 "This is a plot title"

?commands call old-style
?call old-style
 This describes the deprecated call mechanism used by old versions of gnuplot.

call "<input-file>" <param-0> <param-1> ... <param-9>

The name of the input file must be enclosed in quotes.
 As each line is read from the input file, it is scanned for the following
 special character sequences: $0 $1 $2 $3 $4 $5 $6 $7 $8 $9 $#.  If found, the
 sequence `$`+digit is replaced by the corresponding parameter from the `call`
 command line. Quote characters are not copied and string variable substitution
 is not performed. The character sequence `$#` is replaced by the number of
 passed parameters. `$` followed by any other character is treated as an escape
 sequence; use `$$` to get a single `$`.

Example:

If the file 'calltest.gp' contains the line:
       print "argc=$# p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"

entering the command:
       call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"

will display:
       argc=7 p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx

NOTES: This use of the `$` character conflicts both with gnuplot's own syntax
 for datafile columns and with the use of `$` to indicate environmental
 variables in a unix-like shell. The special sequence `$#` was mis-interpreted
 as a comment delimiter in gnuplot versions 4.5 through 4.6.3.  Quote characters
 are ignored during substitution, so string constants are easily corrupted.
?commands clear
?clear
?inset
 The `clear` command erases the current screen or output device as specified
 by `set terminal` and `set output`.  This usually generates a formfeed on
 hardcopy devices.

For some terminals `clear` erases only the portion of the plotting surface
 defined by `set size`, so for these it can be used in conjunction with `set
 multiplot` to create an inset.

Example:
       set multiplot
       plot sin(x)
       set origin 0.5,0.5
       set size 0.4,0.4
       clear
       plot cos(x)
       unset multiplot

Please see `set multiplot`, `set size`, and `set origin` for details.
?commands continue
?continue
 The `continue` command is only meaningful inside the bracketed iteration clause
 of a `do` or `while` statement.  It causes the remaining statements inside the
 bracketed clause to be skipped.  Execution resumes at the start of the next
 iteration (if any remain in the loop condition).  See also `break`.
?commands do
?do
 Syntax:
       do for <iteration-spec> {
            <commands>
            <commands>
       }
 Execute a sequence of commands multiple times.  The commands must be enclosed
 in curly brackets, and the opening "{" must be on the same line as the `do`
 keyword.  This command cannot be used with old-style (un-bracketed) if/else
 statements.  See `if`.  For examples of iteration specifiers, see `iteration`.
 Example:
       set multiplot layout 2,2
       do for [name in "A B C D"] {
           filename = name . ".dat"
           set title sprintf("Condition %s",name)
           plot filename title name
       }
       unset multiplot
 See also `while`, `continue`, `break`.
?commands evaluate
?evaluate
 The `evaluate` command executes the commands given as an argument string.
 Newline characters are not allowed within the string.

Syntax:
       eval <string expression>

This is especially useful for a repetition of similar commands.

Example:
       set_label(x, y, text) \
         = sprintf("set label '%s' at %f, %f point pt 5", text, x, y)
       eval set_label(1., 1., 'one/one')
       eval set_label(2., 1., 'two/one')
       eval set_label(1., 2., 'one/two')

Please see `substitution macros` for another way to execute commands
 from a string.
?commands exit
?exit
      exit
      exit message "error message text"
      exit status <integer error code>

The commands `exit` and `quit`, as well as the END-OF-FILE character (usually
 Ctrl-D) terminate input from the current input stream: terminal session, pipe,
 or file input (pipe).  If input streams are nested (inherited `load` scripts),
 then reading will continue in the parent stream. When the top level stream is
 closed, the program itself will exit.

The command `exit gnuplot` will immediately and unconditionally cause gnuplot
 to exit even if the input stream is multiply nested.  In this case any open
 output files may not be completed cleanly. Example of use:

bind "ctrl-x" "unset output; exit gnuplot"

The command `exit error "error message"` simulates a program error.
 In interactive mode it prints the error message and returns to the command
 line, breaking out of all nested loops or calls.  In non-interactive mode
 the program will exit.

When gnuplot exits to the controlling shell, the return value is not usually
 informative. This variant of the command allows you to return a specific value.

exit status <value>

See help for `batch/interactive` for more details.
?commands fit
?fit
?least-squares
?Marquardt
 The `fit` command fits a user-supplied real-valued expression to a set of
 data points, using the nonlinear least-squares Marquardt-Levenberg
 algorithm. There can be up to 12 independent variables, there is always 1
 dependent variable, and any number of parameters can be fitted.
 Optionally, error estimates can be input for weighting the data points.

The basic use of `fit` is best explained by a simple example:

f(x) = a + b*x + c*x**2
       fit f(x) 'measured.dat' using 1:2 via a,b,c
       plot 'measured.dat' u 1:2, f(x)

Syntax:
       fit {<ranges>} <expression>
           '<datafile>' {datafile-modifiers}
           {{unitweights} | {y|xy|z}error | errors <var1>{,<var2>,...}}
           via '<parameter file>' | <var1>{,<var2>,...}

Ranges may be specified to filter the data used in fitting.
 Out-of-range data points are ignored. The syntax is
       [{dummy_variable=}{<min>}{:<max>}],
 analogous to `plot`; see `plot ranges`.

<expression> can be any valid `gnuplot` expression, although the most common is
 a previously user-defined function of the form f(x) or f(x,y). It must be
 real-valued.
 The names of the independent variables are set by the `set dummy` command,
 or in the <ranges> part of the command (see below); by default, the first
 two are called x and y.
 Furthermore, the expression should depend on one or more variables whose
 value is to be determined by the fitting procedure.

<datafile> is treated as in the `plot` command.  All the `plot datafile`
 modifiers (`using`, `every`,...) except `smooth` are applicable to `fit`.
 See `plot datafile`.

The datafile contents can be interpreted flexibly by providing a `using`
 qualifier as with plot commands. For example to generate the independent
 variable x as the sum of columns 2 and 3, while taking z from column 6 and
 requesting equal weights:

fit ... using ($2+$3):6

In the absence of a `using` specification, the fit implicitly assumes
 there is only a single independent variable. If the file itself, or the
 using specification, contains only a single column of data, the line
 number is taken as the independent variable.
 If a `using` specification is given, there can be up to 12 independent
 variables (and more if specially configured at compile time).

The `unitweights` option, which is the default, causes all data points to be
 weighted equally. This can be changed by using the `errors` keyword to read
 error estimates of one or more of the variables from the data file. These
 error estimates are interpreted as the standard deviation s of the
 corresponding variable value and used to compute a weight for the datum as
 1/s**2.

In case of error estimates of the independent variables, these weights are
 further multiplied by fitting function derivatives according to the
 "effective variance method" (Jay Orear, Am. J. Phys., Vol. 50, 1982).

The `errors` keyword is to be followed by a comma-separated list of one or
 more variable names for which errors are to be input; the dependent variable
 z must always be among them, while independent variables are optional.
 For each variable in this list, an additional column will be read from the
 file, containing that variable's error estimate. Again, flexible
 interpretation is possible by providing the `using` qualifier.
 Note that the number of independent variables is thus implicitly given by the
 total number of columns in the `using` qualifier, minus 1 (for the dependent
 variable), minus the number of variables in the `errors` qualifier.

As an example, if one has 2 independent variables, and errors for the
 first independent variable and the dependent variable, one uses
 the `errors x,z` qualifier, and a `using` qualifier with 5 columns,
 which are interpreted as x:y:z:sx:sz (where x and y are the independent
 variables, z the dependent variable, and sx and sz the standard
 deviations of x and z).

A few shorthands for the `errors` qualifier are available:
 `yerrors` (for fits with 1 column of independent variable), and
 `zerrors` (for the general case) are all equivalent to `errors z`,
 indicating that there is a single extra column with errors of the
 dependent variable.

`xyerrors`, for the case of 1 independent variable, indicates that there
 are two extra columns, with errors of both the independent and the
 dependent variable.  In this case the errors on x and y are treated by
 Orear's effective variance method.

Note that `yerror` and `xyerror` are similar in both form and interpretation
 to the `yerrorlines` and `xyerrorlines` 2D plot styles.

With the command `set fit v4` the fit command syntax is compatible with
 `gnuplot` version 4.  In this case there must be two more `using`
 qualifiers (z and s) than there are independent variables, unless there is
 only one variable.  `gnuplot` then uses the following formats, depending on
 the number of columns given in the `using` specification:

z                           # 1 independent variable (line number)
       x:z                         # 1 independent variable (1st column)
       x:z:s                       # 1 independent variable (3 columns total)
       x:y:z:s                     # 2 independent variables (4 columns total)
       x1:x2:x3:z:s                # 3 independent variables (5 columns total)
       x1:x2:x3:...:xN:z:s         # N independent variables (N+2 columns total)

Please beware that this means that you have to supply z-errors s in a fit with
 two or more independent variables. If you want unit weights you need to supply
 them explicitly by using e.g. then format x:y:z:(1).

The dummy variable names may be changed when specifying a range as noted above.
 The first range corresponds to the first `using` spec, and so on.  A range may
 also be given for z (the dependent variable), in which case data points for
 which f(x,...) is out of the z range will not contribute to the residual being
 minimized.

Multiple datasets may be simultaneously fit with functions of one
 independent variable by making y a 'pseudo-variable', e.g., the dataline
 number, and fitting as two independent variables.  See `fit multi-branch`.

The `via` qualifier specifies which parameters are to be optimized, either
 directly, or by referencing a parameter file.

Examples:
       f(x) = a*x**2 + b*x + c
       g(x,y) = a*x**2 + b*y**2 + c*x*y
       set fit limit 1e-6
       fit f(x) 'measured.dat' via 'start.par'
       fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
       fit f(x) './data/trash.dat' using 1:2:3 yerror via a, b, c
       fit g(x,y) 'surface.dat' using 1:2:3 via a, b, c
       fit a0 + a1*x/(1 + a2*x/(1 + a3*x)) 'measured.dat' via a0,a1,a2,a3
       fit a*x + b*y 'surface.dat' using 1:2:3 via a,b
       fit [*:*][yaks=*:*] a*x+b*yaks 'surface.dat' u 1:2:3 via a,b

fit [][][t=*:*] a*x + b*y + c*t 'foo.dat' using 1:2:3:4 via a,b,c

set dummy x1, x2, x3, x4, x5
       h(x1,x2,x3,x4,s5) = a*x1 + b*x2 + c*x3 + d*x4 + e*x5
       fit h(x1,x2,x3,x4,x5) 'foo.dat' using 1:2:3:4:5:6 via a,b,c,d,e

After each iteration step, detailed information about the current state
 of the fit is written to the display.  The same information about the
 initial and final states is written to a log file, "fit.log".  This file
 is always appended to, so as to not lose any previous fit history;  it
 should be deleted or renamed as desired. By using the command
 `set fit logfile`, the name of the log file can be changed.

If activated by using `set fit errorvariables`, the error for each fitted
 parameter will be stored in a variable named like the parameter, but with
 "_err" appended.  Thus the errors can be used as input for further
 computations.

If `set fit prescale` is activated, fit parameters are prescaled by
 their initial values. This helps the Marquardt-Levenberg routine
 converge more quickly and reliably in cases where parameters differ
 in size by several orders of magnitude.

The fit may be interrupted by pressing Ctrl-C (Ctrl-Break in wgnuplot).
 After the current iteration completes, you have the option to
 (1) stop the fit and accept the current parameter values,
 (2) continue the fit,
 (3) execute a `gnuplot` command as specified by `set fit script` or the
 environment variable `FIT_SCRIPT`.  The default is `replot`, so if you
 had previously plotted both the data and the fitting function in one graph,
 you can display the current state of the fit.

Once `fit` has finished, the `save fit` command may be used to store final
 values in a file for subsequent use as a parameter file.   See `save fit`
 for details.
?commands fit parameters
?fit parameters
?commands fit adjustable_parameters
?fit adjustable_parameters
?fit_parameters
 There are two ways that `via` can specify the parameters to be adjusted,
 either directly on the command line or indirectly, by referencing a
 parameter file.  The two use different means to set initial values.

Adjustable parameters can be specified by a comma-separated list of variable
 names after the `via` keyword.  Any variable that is not already defined
 is created with an initial value of 1.0.  However, the fit is more likely
 to converge rapidly if the variables have been previously declared with more
 appropriate starting values.

In a parameter file, each parameter to be varied and a corresponding initial
 value are specified, one per line, in the form
       varname = value

Comments, marked by '#', and blank lines are permissible.  The
 special form
       varname = value       # FIXED

means that the variable is treated as a 'fixed parameter', initialized by the
 parameter file, but not adjusted by `fit`.  For clarity, it may be useful to
 designate variables as fixed parameters so that their values are reported by
 `fit`.  The keyword `# FIXED` has to appear in exactly this form.

?commands fit beginners_guide
?fit beginners_guide
?fit guide
?fitting
 `fit` is used to find a set of parameters that 'best' fits your data to your
 user-defined function.  The fit is judged on the basis of the sum of the
 squared differences or 'residuals' (SSR) between the input data points and
 the function values, evaluated at the same places.  This quantity is often
 called 'chisquare' (i.e., the Greek letter chi, to the power of 2).  The
 algorithm attempts to minimize SSR, or more precisely, WSSR, as the residuals
 are 'weighted' by the input data errors (or 1.0) before being squared;
 see `fit error_estimates` for details.

That's why it is called 'least-squares fitting'.  Let's look at an example
 to see what is meant by 'non-linear', but first we had better go over some
 terms.  Here it is convenient to use z as the dependent variable for
 user-defined functions of either one independent variable, z=f(x), or two
 independent variables, z=f(x,y).  A parameter is a user-defined variable
 that `fit` will adjust, i.e., an unknown quantity in the function
 declaration.  Linearity/non-linearity refers to the relationship of the
 dependent variable, z, to the parameters which `fit` is adjusting, not of
 z to the independent variables, x and/or y.  (To be technical, the
 second {and higher} derivatives of the fitting function with respect to
 the parameters are zero for a linear least-squares problem).

For linear least-squares (LLS), the user-defined function will be a sum of
 simple functions, not involving any parameters, each multiplied by one
 parameter.  NLLS handles more complicated functions in which parameters can
 be used in a large number of ways.  An example that illustrates the
 difference between linear and nonlinear least-squares is the Fourier series.
 One member may be written as
      z=a*sin(c*x) + b*cos(c*x).
 If a and b are the unknown parameters and c is constant, then estimating
 values of the parameters is a linear least-squares problem.  However, if
 c is an unknown parameter, the problem is nonlinear.

In the linear case, parameter values can be determined by comparatively
 simple linear algebra, in one direct step.  However LLS is a special case
 which is also solved along with more general NLLS problems by the iterative
 procedure that `gnuplot` uses.  `fit` attempts to find the minimum by doing
 a search.  Each step (iteration) calculates WSSR with a new set of parameter
 values.  The Marquardt-Levenberg algorithm selects the parameter values for
 the next iteration.  The process continues until a preset criterion is met,
 either (1) the fit has "converged" (the relative change in WSSR is less than
 a certain limit, see `set fit limit`), or (2) it reaches a preset iteration
 count limit (see `set fit maxiter`).  The fit may also be interrupted
 and subsequently halted from the keyboard (see `fit`).  The user variable
 FIT_CONVERGED contains 1 if the previous fit command terminated due to
 convergence; it contains 0 if the previous fit terminated for any other
 reason. FIT_NITER contains the number of iterations that were done during the last fit.

Often the function to be fitted will be based on a model (or theory) that
 attempts to describe or predict the behaviour of the data.  Then `fit` can
 be used to find values for the free parameters of the model, to determine
 how well the data fits the model, and to estimate an error range for each
 parameter.  See `fit error_estimates`.

Alternatively, in curve-fitting, functions are selected independent of
 a model (on the basis of experience as to which are likely to describe
 the trend of the data with the desired resolution and a minimum number
 of parameters*functions.)  The `fit` solution then provides an analytic
 representation of the curve.

However, if all you really want is a smooth curve through your data points,
 the `smooth` option to `plot` may be what you've been looking for rather
 than `fit`.
?commands fit error_estimates
?fit error_estimates
?fit errors
 In `fit`, the term "error" is used in two different contexts, data error
 estimates and parameter error estimates.

Data error estimates are used to calculate the relative weight of each data
 point when determining the weighted sum of squared residuals, WSSR or
 chisquare.  They can affect the parameter estimates, since they determine
 how much influence the deviation of each data point from the fitted function
 has on the final values.  Some of the `fit` output information, including
 the parameter error estimates, is more meaningful if accurate data error
 estimates have been provided.

The `statistical overview` describes some of the `fit` output and gives some
 background for the 'practical guidelines'.
?commands fit error statistical_overview
?fit error statistical_overview
?statistical_overview
 The theory of non-linear least-squares (NLLS) is generally described in terms
 of a normal distribution of errors, that is, the input data is assumed to be
 a sample from a population having a given mean and a Gaussian (normal)
 distribution about the mean with a given standard deviation.  For a sample of
 sufficiently large size, and knowing the population standard deviation, one
 can use the statistics of the chisquare distribution to describe a "goodness
 of fit" by looking at the variable often called "chisquare".  Here, it is
 sufficient to say that a reduced chisquare (chisquare/degrees of freedom,
 where degrees of freedom is the number of datapoints less the number of
 parameters being fitted) of 1.0 is an indication that the weighted sum of
 squared deviations between the fitted function and the data points is the
 same as that expected for a random sample from a population characterized by
 the function with the current value of the parameters and the given standard
 deviations.

If the standard deviation for the population is not constant, as in counting
 statistics where variance = counts, then each point should be individually
 weighted when comparing the observed sum of deviations and the expected sum
 of deviations.

At the conclusion `fit` reports 'stdfit', the standard deviation of the fit,
 which is the rms of the residuals, and the variance of the residuals, also
 called 'reduced chisquare' when the data points are weighted.  The number of
 degrees of freedom (the number of data points minus the number of fitted
 parameters) is used in these estimates because the parameters used in
 calculating the residuals of the datapoints were obtained from the same data.
 If the data points have weights, `gnuplot` calculates the so-called p-value,
 i.e. one minus the cumulative distribution function of the
 chisquare-distribution for the number of degrees of freedom and the resulting
 chisquare, see `practical_guidelines`.
 These values are exported to the variables
       FIT_NDF = Number of degrees of freedom
       FIT_WSSR = Weighted sum-of-squares residual
       FIT_STDFIT = sqrt(WSSR/NDF)
       FIT_P = p-value

To estimate confidence levels for the parameters, one can use the minimum
 chisquare obtained from the fit and chisquare statistics to determine the
 value of chisquare corresponding to the desired confidence level, but
 considerably more calculation is required to determine the combinations of
 parameters which produce such values.

Rather than determine confidence intervals, `fit` reports parameter error
 estimates which are readily obtained from the variance-covariance matrix
 after the final iteration.  By convention, these estimates are called
 "standard errors" or "asymptotic standard errors", since they are calculated
 in the same way as the standard errors (standard deviation of each parameter)
 of a linear least-squares problem, even though the statistical conditions for
 designating the quantity calculated to be a standard deviation are not
 generally valid for the NLLS problem.  The asymptotic standard errors are
 generally over-optimistic and should not be used for determining confidence
 levels, but are useful for qualitative purposes.

The final solution also produces a correlation matrix indicating correlation of
 parameters in the region of the solution; The main diagonal elements,
 autocorrelation, are always 1; if all parameters were independent, the
 off-diagonal elements would be nearly 0.  Two variables which completely
 compensate each other would have an off-diagonal element of unit magnitude,
 with a sign depending on whether the relation is proportional or inversely
 proportional.  The smaller the magnitudes of the off-diagonal elements, the
 closer the estimates of the standard deviation of each parameter would be to
 the asymptotic standard error.
?commands fit error practical_guidelines
?fit error practical_guidelines
?practical_guidelines
?guidelines
 If you have a basis for assigning weights to each data point, doing so lets
 you make use of additional knowledge about your measurements, e.g., take into
 account that some points may be more reliable than others.  That may affect
 the final values of the parameters.

Weighting the data provides a basis for interpreting the additional `fit`
 output after the last iteration.  Even if you weight each point equally,
 estimating an average standard deviation rather than using a weight of 1
 makes WSSR a dimensionless variable, as chisquare is by definition.

Each fit iteration will display information which can be used to evaluate
 the progress of the fit.  (An '*' indicates that it did not find a smaller
 WSSR and is trying again.)  The 'sum of squares of residuals', also called
 'chisquare', is the WSSR between the data and your fitted function; `fit`
 has minimized that.  At this stage, with weighted data, chisquare is expected
 to approach the number of degrees of freedom (data points minus parameters).
 The WSSR can be used to calculate the reduced chisquare (WSSR/ndf) or stdfit,
 the standard deviation of the fit, sqrt(WSSR/ndf).  Both of these are
 reported for the final WSSR.

If the data are unweighted, stdfit is the rms value of the deviation of the
 data from the fitted function, in user units.

If you supplied valid data errors, the number of data points is large enough,
 and the model is correct, the reduced chisquare should be about unity.  (For
 details, look up the 'chi-squared distribution' in your favorite statistics
 reference.)  If so, there are additional tests, beyond the scope of this
 overview, for determining how well the model fits the data.

A reduced chisquare much larger than 1.0 may be due to incorrect data error
 estimates, data errors not normally distributed, systematic measurement
 errors, 'outliers', or an incorrect model function.  A plot of the residuals,
 e.g., `plot 'datafile' using 1:($2-f($1))`, may help to show any systematic
 trends.  Plotting both the data points and the function may help to suggest
 another model.

Similarly, a reduced chisquare less than 1.0 indicates WSSR is less than that
 expected for a random sample from the function with normally distributed
 errors.  The data error estimates may be too large, the statistical
 assumptions may not be justified, or the model function may be too general,
 fitting fluctuations in a particular sample in addition to the underlying
 trends.  In the latter case, a simpler function may be more appropriate.

The p-value of the fit is one minus the cumulative distribution function of
 the chisquare-distribution for the number of degrees of freedom and the
 resulting chisquare.  This can serve as a measure of the goodness-of-fit.
 The range of the p-value is between zero and one.  A very small or large
 p-value indicates that the model does not describe the data and its errors
 well.  As described above, this might indicate a problem with the data, its
 errors or the model, or a combination thereof.  A small p-value might
 indicate that the errors have been underestimated and the errors of the
 final parameters should thus be scaled. See also `set fit errorscaling`.

You'll have to get used to both `fit` and the kind of problems you apply it
 to before you can relate the standard errors to some more practical estimates
 of parameter uncertainties or evaluate the significance of the correlation
 matrix.

Note that `fit`, in common with most NLLS implementations, minimizes the
 weighted sum of squared distances (y-f(x))**2.  It does not provide any means
 to account for "errors" in the values of x, only in y.  Also, any "outliers"
 (data points outside the normal distribution of the model) will have an
 exaggerated effect on the solution.
?commands fit control
?fit control
 There are a number of environment variables that can be defined to affect
 `fit` before starting `gnuplot`, see `fit control environment`. At run time
 adjustments to the `fit` command operation can be controlled by `set fit`.
 See `fit control variables`.
?commands fit control variables
?fit control variables
 DEPRECATED in version 5.
 These user variables used to affect fit behaviour.

FIT_LIMIT - use `set fit limit <epsilon>`
     FIT_MAXITER - use `set fit maxiter <number_of_cycles>`
     FIT_START_LAMBDA - use `set fit start-lambda <value>`
     FIT_LAMBDA_FACTOR - use `set fit lambda-factor <value>`
     FIT_SKIP - use the datafile `every` modifier
     FIT_INDEX - See `fit multi-branch`

?commands fit control environment
?fit control environment
 The environment variables must be defined before `gnuplot` is executed; how
 to do so depends on your operating system.

FIT_LOG
 changes the name (and/or path) of the file to which the fit log will be
 written from the default of "fit.log" in the working directory. The default
 value can be overwritten using the command `set fit logfile`.

FIT_SCRIPT
 specifies a command that may be executed after an user interrupt. The default
 is `replot`, but a `plot` or `load` command may be useful to display a plot
 customized to highlight the progress of the fit. This setting can also be
 changed using `set fit script`.
?commands fit multi-branch
?fit multi-branch
?multi-branch
?branch
 In multi-branch fitting, multiple data sets can be simultaneously fit with
 functions of one independent variable having common parameters by minimizing
 the total WSSR.  The function and parameters (branch) for each data set are
 selected by using a 'pseudo-variable', e.g., either the dataline number (a
 'column' index of -1) or the datafile index (-2), as the second independent
 variable.

Example:  Given two exponential decays of the form, z=f(x), each describing
 a different data set but having a common decay time, estimate the values of
 the parameters.  If the datafile has the format x:z:s, then
      f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
      fit f(x,y) 'datafile' using  1:-2:2:3  via a, b, tau

For a more complicated example, see the file "hexa.fnc" used by the
 "fit.dem" demo.

Appropriate weighting may be required since unit weights may cause one
 branch to predominate if there is a difference in the scale of the dependent
 variable.  Fitting each branch separately, using the multi-branch solution
 as initial values, may give an indication as to the relative effect of each
 branch on the joint solution.
?commands fit starting_values
?fit starting_values
?starting_values
 Nonlinear fitting is not guaranteed to converge to the global optimum (the
 solution with the smallest sum of squared residuals, SSR), and can get stuck
 at a local minimum.  The routine has no way to determine that;  it is up to
 you to judge whether this has happened.

`fit` may, and often will get "lost" if started far from a solution, where
 SSR is large and changing slowly as the parameters are varied, or it may
 reach a numerically unstable region (e.g., too large a number causing a
 floating point overflow) which results in an "undefined value" message
 or `gnuplot` halting.

To improve the chances of finding the global optimum, you should set the
 starting values at least roughly in the vicinity of the solution, e.g.,
 within an order of magnitude, if possible.  The closer your starting values
 are to the solution, the less chance of stopping at a false minimum.  One way
 to find starting values is to plot data and the fitting function on the same
 graph and change parameter values and `replot` until reasonable similarity
 is reached.  The same plot is also useful to check whether the fit found a
 false minimum.

Of course finding a nice-looking fit does not prove there is no "better" fit
 (in either a statistical sense, characterized by an improved goodness-of-fit
 criterion, or a physical sense, with a solution more consistent with the
 model.)  Depending on the problem, it may be desirable to `fit` with various
 sets of starting values, covering a reasonable range for each parameter.
?commands fit tips
?fit tips
?tips
 Here are some tips to keep in mind to get the most out of `fit`.  They're not
 very organized, so you'll have to read them several times until their essence
 has sunk in.

The two forms of the `via` argument to `fit` serve two largely distinct
 purposes.  The `via "file"` form is best used for (possibly unattended) batch
 operation, where you supply the starting parameter values in a file.

The `via var1, var2, ...` form is best used interactively, where the command
 history mechanism may be used to edit the list of parameters to be fitted or
 to supply new startup values for the next try.  This is particularly useful
 for hard problems, where a direct fit to all parameters at once won't work
 without good starting values.  To find such, you can iterate several times,
 fitting only some of the parameters, until the values are close enough to the
 goal that the final fit to all parameters at once will work.

Make sure that there is no mutual dependency among parameters of the function
 you are fitting.  For example, don't try to fit a*exp(x+b), because
 a*exp(x+b)=a*exp(b)*exp(x).  Instead, fit either a*exp(x) or exp(x+b).

A technical issue: The larger the ratio of the largest and the
 smallest absolute parameter values, the slower the fit will converge.
 If the ratio is close to or above the inverse of the machine floating
 point precision, it may take next to forever to converge, or refuse
 to converge at all.  You will either have to adapt your function to avoid
 this, e.g., replace 'parameter' by '1e9*parameter' in the function
 definition, and divide the starting value by 1e9 or use `set fit prescale`
 which does this internally according to the parameter starting values.

If you can write your function as a linear combination of simple functions
 weighted by the parameters to be fitted, by all means do so.  That helps a
 lot, because the problem is no longer nonlinear and should converge with only
 a small number of iterations, perhaps just one.

Some prescriptions for analysing data, given in practical experimentation
 courses, may have you first fit some functions to your data, perhaps in a
 multi-step process of accounting for several aspects of the underlying
 theory one by one, and then extract the information you really wanted from
 the fitting parameters of those functions.  With `fit`, this may often be
 done in one step by writing the model function directly in terms of the
 desired parameters.  Transforming data can also quite often be avoided,
 though sometimes at the cost of a more difficult fit problem.  If you think
 this contradicts the previous paragraph about simplifying the fit function,
 you are correct.

A "singular matrix" message indicates that this implementation of the
 Marquardt-Levenberg algorithm can't calculate parameter values for the next
 iteration.  Try different starting values, writing the function in another
 form, or a simpler function.

Finally, a nice quote from the manual of another fitting package (fudgit),
 that kind of summarizes all these issues:  "Nonlinear fitting is an art!"
?commands help
?help
 The `help` command displays built-in help. To specify information on a
 particular topic use the syntax:

help {<topic>}

If <topic> is not specified, a short message is printed about `gnuplot`.
 After help for the requested topic is given, a menu of subtopics is given;
 help for a subtopic may be requested by typing its name, extending the help
 request.  After that subtopic has been printed, the request may be extended
 again or you may go back one level to the previous topic.  Eventually, the
 `gnuplot` command line will return.

If a question mark (?) is given as the topic, the list of topics currently
 available is printed on the screen.
?commands history
?history
 The `history` command prints or saves previous commands in the history list,
 or reexecutes a previous entry in the list.  To modify the behavior of this
 command, see `set history`.

Input lines with `history` as their first command are not stored in the
 command history.

Examples:

history               # show the complete history
       history 5             # show last 5 entries in the history
       history quiet 5       # show last 5 entries without entry numbers
       history "hist.gp"     # write the complete history to file hist.gp
       history "hist.gp" append # append the complete history to file hist.gp
       history 10 "hist.gp"  # write last 10 commands to file hist.gp
       history 10 "|head -5 >>diary.gp" # write 5 history commands using pipe
       history ?load         # show all history entries starting with "load"
       history ?"set c"      # like above, several words enclosed in quotes
       hist !"set xr"        # like above, several words enclosed in quotes
       hist !55              # reexecute the command at history entry 55
?commands if
?if
 New syntax:
       if (<condition>) { <commands>;
              <commands>
              <commands>
       } else {
              <commands>
       }
 Old syntax:
       if (<condition>) <command-line> [; else if (<condition>) ...; else ...]

This version of gnuplot supports block-structured if/else statements. If the
 keyword `if` or `else` is immediately followed by an opening "{", then
 conditional execution applies to all statements, possibly on multiple input
 lines, until a matching "}" terminates the block.  If commands may be nested.

The old single-line if/else syntax is still supported, but can not be
 mixed with the new block-structured syntax.  See `if-old`.
?if if-old
?if-old
 Through gnuplot version 4.4, the scope of the if/else commands was limited to
 a single input line. Now a multi-line clause may be enclosed in curly brackets.
 The old syntax is still honored but cannot be used inside a bracketed clause.

If no opening "{" follows the `if` keyword, the command(s) in <command-line>
 will be executed if <condition> is true (non-zero) or skipped if <condition> is
 false (zero). Either case will consume commands on the input line until the
 end of the line or an occurrence of `else`.  Note that use of `;` to allow
 multiple commands on the same line will _not_ end the conditionalized commands.

Examples:
       pi=3
       if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
 will display:
       ?Fixing pi!
       3.14159265358979
 but
       if (1==2) print "Never see this"; print "Or this either"
 will not display anything.

else:
       v=0
       v=v+1; if (v%2) print "2" ; else if (v%3) print "3"; else print "fred"
 (repeat the last line repeatedly!)
?for
 The `plot`, `splot`, `set` and `unset` commands may optionally contain an
 iteration for clause.  This has the effect of executing the basic command
 multiple times, each time re-evaluating any expressions that make use of the
 iteration control variable.  Iteration of arbitrary command sequences can be
 requested using the `do` command.
 Two forms of iteration clause are currently supported:

for [intvar = start:end{:increment}]
       for [stringvar in "A B C D"]

Examples:

plot for [filename in "A.dat B.dat C.dat"] filename using 1:2 with lines
       plot for [basename in "A B C"] basename.".dat" using 1:2 with lines
       set for [i = 1:10] style line i lc rgb "blue"
       unset for [tag = 100:200] label tag

Nested iteration is supported:

set for [i=1:9] for [j=1:9] label i*10+j sprintf("%d",i*10+j) at i,j

See additional documentation for `iteration`, `do`.
?commands import
?import
 The `import` command associates a user-defined function name with a function
 exported by an external shared object.  This constitutes a plugin mechanism
 that extends the set of functions available in gnuplot. See `plugins`.

Syntax:
       import func(x[,y,z,...]) from "sharedobj[:symbol]"

Examples:
       # make the function myfun, exported by "mylib.so" or "mylib.dll"
       # available for plotting or numerical calculation in gnuplot
       import myfun(x) from "mylib"
       import myfun(x) from "mylib:myfun"    # same as above

# make the function theirfun, defined in "theirlib.so" or "theirlib.dll"
       # available under a different name
       import myfun(x,y,z) from "theirlib:theirfun"

The program extends the name given for the shared object by either ".so" or
 ".dll" depending on the operating system, and searches for it first as a full
 path name and then as a path relative to the current directory. The operating
 system itself may also search any directories in LD_LIBRARY_PATH or
 DYLD_LIBRARY_PATH.

?commands load
?load
 The `load` command executes each line of the specified input file as if it
 had been typed in interactively.  Files created by the `save` command can
 later be `load`ed.  Any text file containing valid commands can be created
 and then executed by the `load` command.  Files being `load`ed may themselves
 contain `load` or `call` commands.  See `comments` for information about
 comments in commands.  To `load` with arguments, see `call`.

Syntax:
       load "<input-file>"

The name of the input file must be enclosed in quotes.

The special filename "-" may be used to `load` commands from standard input.
 This allows a `gnuplot` command file to accept some commands from standard
 input.  Please see help for `batch/interactive` for more details.

On some systems which support a popen function (Unix), the load file can be
 read from a pipe by starting the file name with a '<'.

Examples:
       load 'work.gnu'
       load "func.dat"
       load "< loadfile_generator.sh"

The `load` command is performed implicitly on any file names given as
 arguments to `gnuplot`.  These are loaded in the order specified, and
 then `gnuplot` exits.
 See `raise`.
?commands pause
?pause
?pause mouse
 The `pause` command displays any text associated with the command and then
 waits a specified amount of time or until the carriage return is pressed.
 `pause` is especially useful in conjunction with `load` files.

Syntax:
       pause <time> {"<string>"}
       pause mouse {<endcondition>}{, <endcondition>} {"<string>"}
       pause mouse close

<time> may be any constant or floating-point expression.  `pause -1` will wait
 until a carriage return is hit, zero (0) won't pause at all, and a positive
 number will wait the specified number of seconds.
 `pause 0` is synonymous with `print`.

If the current terminal supports `mousing`, then `pause mouse` will terminate
 on either a mouse click or on ctrl-C.  For all other terminals, or if mousing
 is not active, `pause mouse` is equivalent to `pause -1`.

If one or more end conditions are given after `pause mouse`, then any one of
 the conditions will terminate the pause. The possible end conditions are
 `keypress`, `button1`, `button2`, `button3`, `close`, and `any`.
 If the pause terminates on a keypress, then the ascii value of the key pressed
 is returned in MOUSE_KEY.  The character itself is returned as a one character
 string in MOUSE_CHAR. Hotkeys (bind command) are disabled if keypress is one of
 the end conditions.  Zooming is disabled if button3 is one of the end
 conditions.

In all cases the coordinates of the mouse are returned in variables MOUSE_X,
 MOUSE_Y, MOUSE_X2, MOUSE_Y2.  See `mouse variables`.

Note: Since `pause` communicates with the operating system rather than the
 graphics, it may behave differently with different device drivers (depending
 upon how text and graphics are mixed).

Examples:
       pause -1    # Wait until a carriage return is hit
       pause 3     # Wait three seconds
       pause -1  "Hit return to continue"
       pause 10  "Isn't this pretty?  It's a cubic spline."
       pause mouse "Click any mouse button on selected data point"
       pause mouse keypress "Type a letter from A-F in the active window"
       pause mouse button1,keypress
       pause mouse any "Any key or button will terminate"

The variant "pause mouse key" will resume after any keypress in the active
 plot window. If you want to wait for a particular key to be pressed, you can
 use a loop such as:

print "I will resume after you hit the Tab key in the plot window"
       plot <something>
       pause mouse key
       while (MOUSE_KEY != 9) {
           pause mouse key
       }
?commands pause mouse close
?pause mouse close
?pause close
 The command `pause mouse close` is a specific example of pausing to wait for
 an external event.  In this case the program waits for a "close" event from
 the plot window.  Exactly how to generate such an event varies with your
 desktop environment and configuration, but usually you can close the plot
 window by clicking on some widget on the window border or by typing
 a hot-key sequence such as <alt><F4> or <ctrl>q.  If you are unsure whether
 a suitable widget or hot-key is available to the user, you may also want to
 define a hot-key sequence using gnuplot's own mechanism. See `bind`.

The command sequence below may be useful when running gnuplot from a script
 rather than from the command line.

plot <...whatever...>
      bind all "alt-End" "exit gnuplot"
      pause mouse close

?commands plot
?plot
 `plot` is the primary command for drawing plots with `gnuplot`.  It offers
 many different graphical representations for functions and data.
 `plot` is used to draw 2D functions and data.
 `splot` draws 2D projections of 3D surfaces and data.

Syntax:
       plot {<ranges>} <plot-element> {, <plot-element>, <plot-element>}

Each plot element consists of a definition, a function, or a data source
 together with optional properties or modifiers:
       plot-element:
            {<iteration>}
            <definition> | {sampling-range} <function> | <data source>
                         | keyentry
            {axes <axes>} {<title-spec>}
            {with <style>}

The graphical representation of each plot element is determined by the keyword
 `with`, e.g. `with lines` or `with boxplot`.   See `plotting styles`.

The data to be plotted is either generated by a function (two functions if in
 parametric mode), read from a data file, or read from a named data block that
 was defined previously.  Multiple datafiles, data blocks, and/or functions may
 be plotted in a single plot command separated by commas.
 See `data`, `inline data`, `functions`.

A plot-element that contains the definition of a function or variable does not
 create any visible output, see third example below.

Examples:
       plot sin(x)
       plot sin(x), cos(x)
       plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
       plot "datafile.1" with lines, "datafile.2" with points
       plot [t=1:10] [-pi:pi*2] tan(t), \
            "data.1" using (tan($2)):($3/$4) smooth csplines \
                     axes x1y2 notitle with lines 5
       plot for [datafile in "spinach.dat broccoli.dat"] datafile

See also `show plot`.
?commands plot axes
?plot axes
?axes
 There are four possible sets of axes available; the keyword <axes> is used to
 select the axes for which a particular line should be scaled.  `x1y1` refers
 to the axes on the bottom and left; `x2y2` to those on the top and right;
 `x1y2` to those on the bottom and right; and `x2y1` to those on the top and
 left.  Ranges specified on the `plot` command apply only to the first set of
 axes (bottom left).
?binary
?data binary
?datafile binary
?plot data binary
 BINARY DATA FILES:

It is necessary to provide the keyword `binary` after the filename.
 Adequate details of the file format must be given on the command line or
 extracted from the file itself for a supported binary `filetype`.
 In particular, there are two structures for binary files,  binary matrix
 format and binary general format.

The `binary matrix` format contains a two dimensional array of 32 bit IEEE
 float values plus an additional column and row of coordinate values.  In the
 `using` specifier of a plot command, column 1 refers to the matrix row
 coordinate, column 2 refers to the matrix column coordinate, and column 3
 refers to the value stored in the array at those coordinates.

The `binary general` format contains an arbitrary number of columns for which
 information must be specified at the command line.  For example, `array`,
 `record`, `format` and `using` can indicate the size, format and dimension
 of data.  There are a variety of useful commands for skipping file headers
 and changing endianess.  There are a set of commands for positioning and
 translating data since often coordinates are not part of the file when uniform
 sampling is inherent in the data.  Unlike reading from a text or matrix binary
 file, general binary does not treat the generated columns as 1, 2 or 3 in the
 `using` list. Instead column 1 refers to column 1 of the file, or as specified
 in the `format` list.

There are global default settings for the various binary options which may
 be set using the same syntax as the options when used as part of the `(s)plot
 <filename> binary ...` command.  This syntax is `set datafile binary ...`.
 The general rule is that common command-line specified parameters override
 file-extracted parameters which override default parameters.

`Binary matrix` is the default binary format when no keywords specific to
 `binary general` are given, i.e., `array`, `record`, `format`, `filetype`.

General binary data can be entered at the command line via the special file
 name '-'.  However, this is intended for use through a pipe where programs
 can exchange binary data, not for keyboards.  There is no "end of record"
 character for binary data.  Gnuplot continues reading from a pipe until it
 has read the number of points declared in the `array` qualifier.
 See `binary matrix` or `binary general` for more details.

The `index` keyword is not supported, since the file format allows only one
 surface per file.  The `every` and `using` filters are supported.  `using`
 operates as if the data were read in the above triplet form.
 Binary File Splot Demo.
?commands plot binary general
?commands splot binary general
?plot binary general
?splot binary general
?datafile binary general
?data binary general
?binary general
 The `binary` keyword appearing alone indicates a binary data file that
 contains both coordinate information describing a non-uniform grid and
 the value of each grid point (see `binary matrix`).  Binary data in any other
 format requires additional keywords to describe the layout of the data.
 Unfortunately the syntax of these required additional keywords is convoluted.
 Nevertheless the general binary mode is particularly useful for application
 programs sending large amounts of data to gnuplot.

Syntax:
       plot '<file_name>' {binary <binary list>} ...
       splot '<file_name>' {binary <binary list>} ...

General binary format is activated by keywords in <binary list> pertaining
 to information about file structure, i.e., `array`, `record`, `format` or
 `filetype`.  Otherwise, non-uniform matrix binary format is assumed.
 (See `binary matrix` for more details.)

Gnuplot knows how to read a few standard binary file types that are fully
 self-describing, e.g. PNG images.  Type `show datafile binary` at the
 command line for a list. Apart from these, you can think of binary data
 files as conceptually the same as text data.  Each point has columns of
 information which are selected via the `using` specification.  If no `format`
 string is specified, gnuplot will read in a number of binary values equal
 to the largest column given in the `<using list>`.  For example, `using 1:3`
 will result in three columns being read, of which the second will be ignored.
 Certain plot types have an associated default using specification.
 For example, `with image` has a default of `using 1`, while `with rgbimage`
 has a default of `using 1:2:3`.
?binary array
 Describes the sampling array dimensions associated with the binary file.
 The coordinates will be generated by gnuplot.  A number must be specified
 for each dimension of the array.  For example, `array=(10,20)` means the
 underlying sampling structure is two-dimensional with 10 points along the
 first (x) dimension and 20 points along the second (y) dimension.
 A negative number indicates that data should be read until the end of file.
 If there is only one dimension, the parentheses may be omitted.
 A colon can be used to separate the dimensions for multiple records.
 For example, `array=25:35` indicates there are two one-dimensional records in
 the file.
?binary record
 This keyword serves the same function as `array` and has the same syntax.
 However, `record` causes gnuplot to not generate coordinate information.
 This is for the case where such information may be included in one of the
 columns of the binary data file.
?binary skip
 This keyword allows you to skip sections of a binary file. For instance, if the
 file contains a 1024 byte header before the start of the data region you would
 probably want to use
       plot '<file_name>' binary skip=1024 ...
 If there are multiple records in the file, you may specify a leading offset for
 each. For example, to skip 512 bytes before the 1st record and 256 bytes before
 the second and third records
       plot '<file_name> binary record=356:356:356 skip=512:256:256 ...
?binary format
 The default binary format is a float.  For more flexibility, the format can
 include details about variable sizes.  For example, `format="%uchar%int%float"`
 associates an unsigned character with the first using column, an int with the
 second column and a float with the third column.  If the number of size
 specifications is less than the greatest column number, the size is implicitly
 taken to be similar to the last given variable size.

Furthermore, similar to the `using` specification, the format can include
 discarded columns via the `*` character and have implicit repetition via a
 numerical repeat-field.  For example, `format="%*2int%3float"` causes gnuplot
 to discard two ints before reading three floats.  To list variable sizes, type
 `show datafile binary datasizes`.  There are a group of names that are machine
 dependent along with their sizes in bytes for the particular compilation.
 There is also a group of names which attempt to be machine independent.
?binary endian
 Often the endianess of binary data in the file does not agree with the
 endianess used by the platform on which gnuplot is running.  Several words can
 direct gnuplot how to arrange bytes.  For example `endian=little` means treat
 the binary file as having byte significance from least to greatest. The options
 are

little:  least significant to greatest significance
                  big:  greatest significance to least significance
              default:  assume file endianess is the same as compiler
          swap (swab):  Interchange the significance.  (If things
                        don't look right, try this.)

Gnuplot can support "middle" ("pdp") endian if it is compiled with that option.
?binary filetype
?filetype
 For some standard binary file formats gnuplot can extract all the necessary
 information from the file in question.  As an example, "format=edf" will read
 ESRF Header File format files.  For a list of the currently supported file
 formats, type `show datafile binary filetypes`.

There is a special file type called `auto` for which gnuplot will check if the
 binary file's extension is a quasi-standard extension for a supported format.

Command line keywords may be used to override settings extracted from the file.
 The settings from the file override any defaults.  See `set datafile binary`.
?binary filetype avs
?filetype avs
?avs
 `avs` is one of the automatically recognized binary file types for images.
 AVS is an extremely simple format, suitable mostly for streaming between
 applications. It consists of 2 longs (xwidth, ywidth) followed by a stream
 of pixels, each with four bytes of information alpha/red/green/blue.
?binary filetype edf
?filetype edf
?edf
?filetype ehf
?ehf
 `edf` is one of the automatically recognized binary file types for images.
 EDF stands for ESRF Data Format, and it supports both edf and ehf formats
 (the latter means ESRF Header Format).  More information on specifications
 can be found at

http://www.edfplus.info/specs
?binary filetype png
?binary filetype gif
?binary filetype jpeg
?filetype png
?filetype gif
?filetype jpeg
 If gnuplot was configured to use the libgd library for png/gif/jpeg output,
 then it can also be used to read these same image types as binary files.
 You can use an explicit command
       plot 'file.png' binary filetype=png
 Or the file type will be recognized automatically from the extension if you
 have previously requested
       set datafile binary filetype=auto
?binary keywords
 The following keywords apply only when generating coordinates from binary
 data files.  That is, the control mapping the individual elements of a binary
 array, matrix, or image to specific x/y/z positions.
?binary keywords scan
?scan
 A great deal of confusion can arise concerning the relationship between how
 gnuplot scans a binary file and the dimensions seen on the plot.  To lessen
 the confusion, conceptually think of gnuplot _always_ scanning the binary file
 point/line/plane or fast/medium/slow.  Then this keyword is used to tell
 gnuplot how to map this scanning convention to the Cartesian convention shown
 in plots, i.e., x/y/z.  The qualifier for scan is a two or three letter code
 representing where point is assigned (first letter), line is assigned (second
 letter), and plane is assigned (third letter).  For example, `scan=yx` means
 the fastest, point-by-point, increment should be mapped along the Cartesian
 y dimension and the middle, line-by-line, increment should be mapped along the
 x dimension.

When the plotting mode is `plot`, the qualifier code can include the two
 letters x and y.  For `splot`, it can include the three letters x, y and z.

There is nothing restricting the inherent mapping from point/line/plane to
 apply only to Cartesian coordinates.  For this reason there are cylindrical
 coordinate synonyms for the qualifier codes where t (theta), r and z are
 analogous to the x, y and z of Cartesian coordinates.
?binary keywords transpose
?transpose
 Shorthand notation for `scan=yx` or `scan=yxz`.  I.e. it affects the assignment
 of pixels to scan lines during input.  To instead transpose an image when it is
 displayed try
      plot 'imagefile' binary filetype=auto flipx rotate=90deg with rgbimage
?binary keywords dx
?binary keywords dy
?dx
?dy
 When gnuplot generates coordinates, it uses the spacing described by these
 keywords.  For example `dx=10 dy=20` would mean space samples along the
 x dimension by 10 and space samples along the y dimension by 20.  `dy` cannot
 appear if `dx` does not appear.  Similarly, `dz` cannot appear if `dy` does not
 appear.  If the underlying dimensions are greater than the keywords specified,
 the spacing of the highest dimension given is extended to the other dimensions.
 For example, if an image is being read from a file and only `dx=3.5` is given
 gnuplot uses a delta x and delta y of 3.5.

The following keywords also apply only when generating coordinates.  However
 they may also be used with matrix binary files.
?binary keywords flipx
?flipx
?flipy
?flipz
 Sometimes the scanning directions in a binary datafile are not consistent with
 that assumed by gnuplot.  These keywords can flip the scanning direction along
 dimensions x, y, z.
?binary keywords origin
?binary origin
 When gnuplot generates coordinates based upon transposition and flip, it
 attempts to always position the lower left point in the array at the origin,
 i.e., the data lies in the first quadrant of a Cartesian system after transpose
 and flip.

To position the array somewhere else on the graph, the `origin` keyword directs
 gnuplot to position the lower left point of the array at a point specified by a
 tuple.  The tuple should be a double for `plot` and a triple for `splot`.
 For example, `origin=(100,100):(100,200)` is for two records in the file and
 intended for plotting in two dimensions. A second example, `origin=(0,0,3.5)`,
 is for plotting in three dimensions.
?binary keywords center
?keywords center
?center
 Similar to `origin`, this keyword will position the array such that its center
 lies at the point given by the tuple.  For example, `center=(0,0)`.  Center
 does not apply when the size of the array is `Inf`.
?binary keywords rotate
?keywords rotate
?rotate
 The transpose and flip commands provide some flexibility in generating and
 orienting coordinates.  However, for full degrees of freedom, it is possible to
 apply a rotational vector described by a rotational angle in two dimensions.

The `rotate` keyword applies to the two-dimensional plane, whether it be `plot`
 or `splot`.  The rotation is done with respect to the positive angle of the
 Cartesian plane.

The angle can be expressed in radians, radians as a multiple of pi, or degrees.
 For example, `rotate=1.5708`, `rotate=0.5pi` and `rotate=90deg` are equivalent.

If `origin` is specified, the rotation is done about the lower left sample
 point before translation.  Otherwise, the rotation is done about the array
 `center`.
?binary keywords perpendicular
?perpendicular
 For `splot`, the concept of a rotational vector is implemented by a triple
 representing the vector to be oriented normal to the two-dimensional x-y plane.
 Naturally, the default is (0,0,1).  Thus specifying both rotate and
 perpendicular together can orient data myriad ways in three-space.

The two-dimensional rotation is done first, followed by the three-dimensional
 rotation.  That is, if R' is the rotational 2 x 2 matrix described by an angle,
 and P is the 3 x 3 matrix projecting (0,0,1) to (xp,yp,zp), let R be
 constructed from R' at the upper left sub-matrix, 1 at element 3,3 and zeros
 elsewhere.  Then the matrix formula for translating data is v' = P R v, where v
 is the 3 x 1 vector of data extracted from the data file.  In cases where the
 data of the file is inherently not three-dimensional, logical rules are used to
 place the data in three-space.  (E.g., usually setting the z-dimension value to
 zero and placing 2D data in the x-y plane.)
?commands plot datafile
?plot datafile
?data-file
?datafile
?data
?file
 Discrete data contained in a file can be displayed by specifying the name of
 the data file (enclosed in single or double quotes) on the `plot` command line.

Syntax:
       plot '<file_name>' {binary <binary list>}
                          {{nonuniform} matrix}
                          {index <index list> | index "<name>"}
                          {every <every list>}
                          {skip <number-of-lines>}
                          {using <using list>}
                          {smooth <option>}
                          {bins <options>}
                          {volatile} {noautoscale}

The modifiers `binary`, `index`, `every`, `skip`, `using`, `bins`, and `smooth`
 are discussed separately.  In brief
 *  `skip N` tells the program to ignore N lines at the start of the input file
 *  `binary` indicates that the file contains binary data rather than text
 *  `index` selects which data sets in a multi-data-set file are to be plotted
 *  `every` specifies which points within a single data set are to be plotted
 *  `using` specifies which columns in the file are to be used in which order
 *  `smooth` performs simple filtering, interpolation, or curve-fitting of the
    data prior to plotting
 *  `bins` sorts individual input points into equal-sized intervals along x and
    plots a single accumulated value per interval
 *  `volatile` indicates that the content of the file may not be available to
    reread later and therefore it should be retained internally for re-use.

`splot` has a similar syntax but does not support `smooth` or `bins`.

The `noautoscale` keyword means that the points making up this plot will be
 ignored when automatically determining axis range limits.

TEXT DATA FILES:

Each non-empty line in a data file describes one data point, except that
 records beginning with `#` (and also with `!` on VMS) will be treated as
 comments and ignored.

Depending on the plot style and options selected, from one to eight values
 are read from each line and associated with a single data point.
 See `using`.

The individual records on a single line of data must be separated by white
 space (one or more blanks or tabs) a special field separator character is
 is specified by the `set datafile` command.  A single field may itself 
 contain white space characters if the entire field is enclosed in a pair of
 double quotes, or if a field separator other than white space is in effect.
 Whitespace inside a pair of double quotes is ignored when counting columns,
 so the following datafile line has three columns:
       1.0 "second column" 3.0

Data may be written in exponential format with the exponent preceded by the
 letter e or E.  The fortran exponential specifiers d, D, q, and Q may also
 be used if the command `set datafile fortran` is in effect.

Blank records in a data file are significant.
 Single blank records designate discontinuities in a `plot`; no line will join
 points separated by a blank records (if they are plotted with a line style).
 Two blank records in a row indicate a break between separate data sets.
 See `index`.

If autoscaling has been enabled (`set autoscale`), the axes are automatically
 extended to include all datapoints, with a whole number of tic marks if tics
 are being drawn.  This has two consequences: i) For `splot`, the corner of
 the surface may not coincide with the corner of the base.  In this case, no
 vertical line is drawn.  ii) When plotting data with the same x range on a
 dual-axis graph, the x coordinates may not coincide if the x2tics are not
 being drawn.  This is because the x axis has been autoextended to a whole
 number of tics, but the x2 axis has not.  The following example illustrates
 the problem:

reset; plot '-', '-' axes x2y1
       1 1
       19 19
       e
       1 1
       19 19
       e

To avoid this, you can use the `noextend` modifier of the `set autoscale`
 or `set [axis]range` commands. This turns off extension of the axis range to
 include the next tic mark.

Label coordinates and text can also be read from a data file (see `labels`).
?commands plot datafile bins
?plot datafile bins
?plot bins
?data-file bins
?datafile bins
?bins
 Syntax:
      plot 'DATA' using <XCOL> {:<YCOL>} bins{=<NBINS>}
           {binrange [<LOW>:<HIGH>]} {binwidth=<width>}
           {binvalue={sum|avg}

The `bins` option to a `plot` command first assigns the original data to
 equal width bins on x and then plots a single value per bin.  The default
 number of bins is controlled by `set samples`, but this can be changed by
 giving an explicit number of bins in the command.

If no binrange is given, the range is taken from the extremes of the x
 values found in 'DATA'.

Given the range and the number of bins, bin width is calculated automatically
 and points are assigned to bins 0 to NBINS-1
      BINWIDTH = (HIGH - LOW) / (NBINS-1)
      xmin = LOW - BINWIDTH/2
      xmax = HIGH + BINWIDTH/2
      first bin holds points with (xmin <= x < xmin + BINWIDTH)
      last bin holds points with (xmax-BINWIDTH <= x < xman)
      each point is assigned to bin i = floor(NBINS * (x-xmin)/(xmax-xmin))

Alternatively you can provide a fixed bin width, in which case nbins is
 calculated as the smallest number of bins that will span the range.

On output bins are plotted or tabulated by midpoint. E.g. if the program
 calculates bin width as shown above, the x coordinate output for the first bin
 is x=LOW (not x=xmin).

If only a single column is given in the using clause then each data point
 contributes a count of 1 to the accumulation of total counts in the bin for
 that x coordinate value.  If a second column is given then the value in that
 column is added to the accumulation for the bin.  Thus the following two plot
 command are equivalent:
      plot 'DATA" using N bins=20
      set samples 20
      plot 'DATA' using (column(N)):(1)

The y value plotted for each bin is the sum of the y values over all
 points in that bin.  This corresponds to `binvalue=sum`.
 EXPERIMENTAL: `binvalue=avg` instead plots the mean y value for that bin.

For related plotting styles see `smooth frequency` and `smooth kdensity`.
?commands plot datafile columnheaders
?data-file columnheaders
?datafile columnheaders
?columnheaders
 Extra lines at the start of a data file may be explicitly ignored using the
 `skip` keyword in the plot command. A single additional line containing text
 column headers may be present.  It is skipped automatically if the plot command
 refers explicitly to column headers, e.g. by using them for titles.
 Otherwise you may need to skip it explicitly either by adding one to the skip
 count or by setting the attribute `set datafile columnheaders`.
 See `skip`, `columnhead`, `autotitle columnheader`, `set datafile`.
?csv files
?datafile csv
 Syntax:
      set datafile separator {whitespace | tab | comma | "chars"}

"csv" is short for "comma-separated values". The term "csv file" is loosely
 applied to files in which data fields are delimited by a specific character,
 not necessarily a comma.  To read data from a csv file you must tell gnuplot
 what the field-delimiting character is.  For instance to read from a file
 using semicolon as a field delimiter:

set datafile separator ";"

See `set datafile separator`.  This applies only to files used for input.
 To create a csv file on output, use the corresponding `separator` option to
 `set table`.
?commands plot datafile every
?plot datafile every
?plot every
?data-file every
?datafile every
?every
 The `every` keyword allows a periodic sampling of a data set to be plotted.

For ordinary files a "point" single record (line); a "block" of data is a set
 of consecutive records with blank lines before and after the block.

For matrix data a "block" and "point" correspond to "row" and "column".
 See `matrix every`.

Syntax:
       plot 'file' every {<point_incr>}
                           {:{<block_incr>}
                             {:{<start_point>}
                               {:{<start_block>}
                                 {:{<end_point>}
                                   {:<end_block>}}}}}

The data points to be plotted are selected according to a loop from
 <`start_point`> to <`end_point`> with increment <`point_incr`> and the
 blocks according to a loop from <`start_block`> to <`end_block`> with
 increment <`block_incr`>.

The first datum in each block is numbered '0', as is the first block in the
 file.

Note that records containing unplottable information are counted.

Any of the numbers can be omitted; the increments default to unity, the start
 values to the first point or block, and the end values to the last point or
 block. ':' at the end of the `every` option is not permitted.
 If `every` is not specified, all points in all lines are plotted.

Examples:
       every :::3::3    # selects just the fourth block ('0' is first)
       every :::::9     # selects the first 10 blocks
       every 2:2        # selects every other point in every other block
       every ::5::15    # selects points 5 through 15 in each block

See
 simple plot demos (simple.dem)
 ,
 Non-parametric splot demos
 , and
 Parametric splot demos
 .
?commands plot datafile example
?plot datafile example
?plot example
?datafile example
?data-file example
?example
 This example plots the data in the file "population.dat" and a theoretical
 curve:

pop(x) = 103*exp((1965-x)/10)
       set xrange [1960:1990]
       plot 'population.dat', pop(x)

The file "population.dat" might contain:

# Gnu population in Antarctica since 1965
          1965   103
          1970   55
          1975   34
          1980   24
          1985   10

Binary examples:

# Selects two float values (second one implicit) with a float value
       # discarded between them for an indefinite length of 1D data.
       plot '<file_name>' binary format="%float%*float" using 1:2 with lines

# The data file header contains all details necessary for creating
       # coordinates from an EDF file.
       plot '<file_name>' binary filetype=edf with image
       plot '<file_name>.edf' binary filetype=auto with image

# Selects three unsigned characters for components of a raw RGB image
       # and flips the y-dimension so that typical image orientation (start
       # at top left corner) translates to the Cartesian plane.  Pixel
       # spacing is given and there are two images in the file.  One of them
       # is translated via origin.
       plot '<file_name>' binary array=(512,1024):(1024,512) format='%uchar' \
            dx=2:1 dy=1:2 origin=(0,0):(1024,1024) flipy u 1:2:3 w rgbimage

# Four separate records in which the coordinates are part of the
       # data file.  The file was created with a endianess different from
       # the system on which gnuplot is running.
       splot '<file_name>' binary record=30:30:29:26 endian=swap u 1:2:3

# Same input file, but this time we skip the 1st and 3rd records
       splot '<file_name>' binary record=30:26 skip=360:348 endian=swap u 1:2:3

See also `binary matrix`.
?commands plot datafile index
?plot datafile index
?plot index
?data-file index
?datafile index
?index
 The `index` keyword allows you to select specific data sets in a multi-data-set
 file for plotting.

Syntax:
       plot 'file' index { <m>{:<n>{:<p>}} | "<name>" }

Data sets are separated by pairs of blank records.  `index <m>` selects only
 set <m>; `index <m>:<n>` selects sets in the range <m> to <n>; and `index
 <m>:<n>:<p>` selects indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at
 <n>.  Following C indexing, the index 0 is assigned to the first data set in
 the file.  Specifying too large an index results in an error message.
 If <p> is specified but <n> is left blank then every <p>-th dataset is read
 until the end of the file.  If `index` is not specified, the entire file is
 plotted as a single data set.

Example:
       plot 'file' index 4:5

For each point in the file, the index value of the data set it appears in is
 available via the pseudo-column `column(-2)`.  This leads to an alternative way
 of distinguishing individual data sets within a file as shown below.  This is
 more awkward than the `index` command if all you are doing is selecting one
 data set for plotting, but is very useful if you want to assign different
 properties to each data set.  See `pseudocolumns`, `lc variable`.

Example:
       plot 'file' using 1:(column(-2)==4 ? $2 : NaN)        # very awkward
       plot 'file' using 1:2:(column(-2)) linecolor variable # very useful!

`index '<name>'` selects the data set with name '<name>'.  Names are assigned
 to data sets in comment lines.  The comment character and leading white space
 are removed from the comment line.  If the resulting line starts with <name>,
 the following data set is now named <name> and can be selected.

Example:
       plot 'file' index 'Population'

Please note that every comment that starts with <name> will name the following
 data set.  To avoid problems it may be useful to choose a naming scheme like
 '== Population ==' or '[Population]'.

?plot datafile skip
?data-file skip
?datafile skip
?skip
 The `skip` keyword tells the program to skip lines at the start of a text
 (i.e. not binary) data file.  The lines that are skipped do not count toward
 the line count used in processing the `every` keyword.  Note that `skip N`
 skips lines only at the start of the file, whereas `every ::N` skips lines at
 the start of every block of data in the file.  See also `binary skip` for a
 similar option that applies to binary data files.
?commands plot datafile smooth
?plot datafile smooth
?plot smooth
?data-file smooth
?datafile smooth
?smooth
?splines
 `gnuplot` includes a few general-purpose routines for filtering, interpolation
 and grouping data as it is input; these are grouped under the `smooth` option.
 More sophisticated data processing may be performed by preprocessing the data
 externally or by using `fit` with an appropriate model.

Syntax:
       smooth {unique | frequency | fnormal | cumulative | cnormal | bins
                      | kdensity {bandwidth} {period}
                      | csplines | acsplines | mcsplines | bezier | sbezier
                      | unwrap | zsort}

The `unique`, `frequency`, `fnormal`, `cumulative` and `cnormal` sort the data
 on x and then plot some aspect of the distribution of x values.

The spline and Bezier options determine coefficients describing a continuous
 curve between the endpoints of the data. This curve is then plotted in the same
 manner as a function, that is, by finding its value at uniform intervals along
 the abscissa (see `set samples`) and connecting these points with straight line
 segments. If the data set is interrupted by blank lines or undefined values a
 separate continuous curve is fit for each uninterrupted subset of the data.
 Adjacent separately fit segments may be separated by a gap or discontinuity.

`unwrap` manipulates the data to avoid jumps of more than pi by adding or
 subtracting multiples of 2*pi.

`zsort` uses a 3rd column of input to sort points prior to plotting.

If `autoscale` is in effect, axis ranges will be computed for the final curve
 rather than for the original data.

If `autoscale` is not in effect, and a spline curve is being generated,
 sampling of the spline fit is done across the intersection of the x range
 covered by the input data and the fixed abscissa range defined by `set xrange`.

If too few points are available to apply the requested smoothing operation
 an error message is produced.

The `smooth` options have no effect on function plots.
?commands plot datafile smooth acsplines
?plot datafile smooth acsplines
?data-file smooth acsplines
?datafile smooth acsplines
?plot smooth acsplines
?plot acsplines
?smooth acsplines
?acsplines
 The `smooth acsplines` option approximates the data with a natural smoothing
 spline.  After the data are made monotonic in x (see `smooth unique`), a curve
 is piecewise constructed from segments of cubic polynomials whose coefficients
 are found by fitting to the individual data points weighted by the value,
 if any, given in the third column of the using spec.  The default is equivalent
 to
       plot 'data-file' using 1:2:(1.0) smooth acsplines

Qualitatively, the absolute magnitude of the weights determines the number
 of segments used to construct the curve.  If the weights are large, the
 effect of each datum is large and the curve approaches that produced by
 connecting consecutive points with natural cubic splines.  If the weights are
 small, the curve is composed of fewer segments and thus is smoother; the
 limiting case is the single segment produced by a weighted linear least
 squares fit to all the data.  The smoothing weight can be expressed in terms
 of errors as a statistical weight for a point divided by a "smoothing factor"
 for the curve so that (standard) errors in the file can be used as smoothing
 weights.

Example:
       sw(x,S)=1/(x*x*S)
       plot 'data_file' using 1:2:(sw($3,100)) smooth acsplines
?commands plot datafile smooth bezier
?plot datafile smooth bezier
?plot smooth bezier
?data-file smooth bezier
?datafile smooth bezier
?plot bezier
?smooth bezier
?bezier
 The `smooth bezier` option approximates the data with a Bezier curve of degree n
 (the number of data points) that connects the endpoints.
?data-file smooth bins
?datafile smooth bins
?smooth bins
 `smooth bins` is the same as `bins`.
 See `bins`.
 For related plotting styles see `smooth frequency` and `smooth kdensity`.
?commands plot datafile smooth csplines
?plot datafile smooth csplines
?plot smooth csplines
?data-file smooth csplines
?datafile smooth csplines
?plot csplines
?smooth csplines
?csplines
 The `smooth csplines` option connects consecutive points by natural cubic
 splines after rendering the data monotonic (see `smooth unique`).
?commands plot datafile smooth mcsplines
?plot datafile smooth mcsplines
?plot smooth mcsplines
?data-file smooth mcsplines
?datafile smooth mcsplines
?plot mcsplines
?smooth mcsplines
?mcsplines
 The `smooth mcsplines` option connects consecutive points by cubic splines
 constrained such that the smoothed function preserves the monotonicity and
 convexity of the original data points.  This reduces the effect of outliers.
 FN Fritsch & RE Carlson (1980) "Monotone Piecewise Cubic Interpolation",
 SIAM Journal on Numerical Analysis 17: 238–246.
?commands plot datafile smooth sbezier
?plot datafile smooth sbezier
?plot smooth sbezier
?data-file smooth sbezier
?datafile smooth sbezier
?plot sbezier
?smooth sbezier
?sbezier
 The `smooth sbezier` option first renders the data monotonic (`unique`) and
 then applies the `bezier` algorithm.
?commands plot datafile smooth unique
?plot datafile smooth unique
?plot smooth unique
?data-file smooth unique
?datafile smooth unique
?plot unique
?smooth unique
?unique
 The `smooth unique` option makes the data monotonic in x; points with the same
 x-value are replaced by a single point having the average y-value.  The
 resulting points are then connected by straight line segments.
?commands plot datafile smooth unwrap
?plot datafile smooth unwrap
?plot smooth unwrap
?data-file smooth unwrap
?datafile smooth unwrap
?plot unwrap
?smooth unwrap
?unwrap
 The `smooth unwrap` option modifies the input data so that any two successive
 points will not differ by more than pi; a point whose y value is outside this
 range will be incremented or decremented by multiples of 2pi until it falls
 within pi of the previous point. This operation is useful for making wrapped
 phase measurements continuous over time.
?commands plot datafile smooth frequency
?plot datafile smooth frequency
?plot smooth frequency
?data-file smooth frequency
?datafile smooth frequency
?plot frequency
?smooth frequency
?frequency
 The `smooth frequency` option makes the data monotonic in x; points with the
 same x-value are replaced by a single point having the summed y-values.
 To plot a histogram of the number of data values in equal size bins,
 set the y-value to 1.0 so that the sum is a count of occurrences in that bin.
 This is done implicitly if only a single column is provided.
 Example:
      binwidth = <something>  # set width of x values in each bin
      bin(val) = binwidth * floor(val/binwidth)
      plot "datafile" using (bin(column(1))):(1.0) smooth frequency
      plot "datafile" using (bin(column(1))) smooth frequency  # same result
 See also
 smooth.dem
?commands plot datafile smooth fnormal
?plot datafile smooth fnormal
?plot smooth fnormal
?data-file smooth fnormal
?datafile smooth fnormal
?plot fnormal
?smooth fnormal
?fnormal
 The `smooth fnormal` option work just like the `frequency` option, but produces
 a normalized histogram. It makes the data monotonic in x and normalises the
 y-values so they all sum to 1. Points with the same x-value are replaced by a
 single point containing the sumed y-values. To plot a histogram of the number
 of data values in equal size bins, set the y-value to 1.0 so that the sum is a
 count of occurrences in that bin. This is done implicitly if only a single
 column is provided.
 See also
 smooth.dem
?commands plot datafile smooth cumulative
?plot datafile smooth cumulative
?plot smooth cumulative
?data-file smooth cumulative
?datafile smooth cumulative
?plot cumulative
?smooth cumulative
?cumulative
 The `smooth cumulative` option makes the data monotonic in x; points with the
 same x-value are replaced by a single point containing the cumulative sum of
 y-values of all data points with lower x-values (i.e. to the left of the
 current data point). This can be used to obtain a cumulative distribution
 function from data.
 See also
 smooth.dem
?commands plot datafile smooth cnormal
?plot datafile smooth cnormal
?plot smooth cnormal
?data-file smooth cnormal
?datafile smooth cnormal
?plot cnormal
?smooth cnormal
?cnormal
 The `smooth cnormal` option makes the data monotonic in x and normalises the
 y-values onto the range [0:1].  Points with the same x-value are replaced by
 a single point containing the cumulative sum of y-values of all data points
 with lower x-values (i.e. to the left of the current data point) divided by
 the total sum of all y-values. This can be used to obtain a normalised
 cumulative distribution function from data (useful when comparing sets of
 samples with differing numbers of members).
 See also
 smooth.dem

?commands plot datafile smooth kdensity
?plot datafile smooth kdensity
?plot smooth kdensity
?data-file smooth kdensity
?datafile smooth kdensity
?plot kdensity
?smooth kdensity
?kdensity
 The `smooth kdensity` option generates and plots a kernel density estimate
 using Gaussian kernels for the distribution from which a set of values was
 drawn.  Values are taken from the first data column, optional weights are
 taken from the second column.  A Gaussian is placed at the location of each
 point and the sum of all these Gaussians is plotted as a function.
 To obtain a normalized histogram, each weight should be 1/number-of-points.
 
 Bandwidth:
 By default gnuplot calculates and uses the bandwidth which would be optimal
 for normally distributed data values.
      default_bandwidth = sigma * (4/3N) ** (0.2)
 This will usually be a very conservative, i.e. broad bandwidth.
 Alternatively, you can provide an explicit bandwidth.
      plot $DATA smooth kdensity bandwidth <value> with boxes
 The bandwidth used in the previous plot is stored in GPVAL_KDENSITY_BANDWIDTH.

Period:
 For periodic data individual Gaussian components should be treated as repeating
 at intervals of one period.  One example is data measured as a function of
 angle, where the period is 2pi.  Another example is data indexed by day-of-year
 and measured over multiple years, where the period is 365.
 In such cases the period should be provided in the plot command:
      plot $ANGULAR_DAT smooth kdensity period 2*pi with lines

?commands plot datafile smooth zsort
?plot datafile smooth zsort
?plot smooth zsort
?smooth zsort
?zsort
 Syntax
      plot FOO using x:y:z:color smooth zsort with points lc palette
 The intended use is to filter presentation of 2D scatter plots with a
 huge number of points so that the distribution of high-scoring points
 remains evident. Sorting the points on z guarantees that points with
 a high z-value will not be obscured by points with lower z-values.
 Limited to plot style "with points".

?special-filenames
?commands plot datafile special-filenames
?plot datafile special-filenames
?plot special-filenames
?datafile special-filenames
?special-filenames ++
?special-filenames +
?+
?++
 There are a few filenames that have a special meaning:  '', '-', '+' and '++'.

The empty filename '' tells gnuplot to re-use the previous input file in the
 same plot command. So to plot two columns from the same input file:

plot 'filename' using 1:2, '' using 1:3

The filename can also be reused over subsequent plot commands, however `save`
 then only records the name in a comment.

The special filenames '+' and '++' are a mechanism to allow the full range of
 `using` specifiers and plot styles with inline functions.  Normally a function
 plot can only have a single y (or z) value associated with each sampled point.
 The pseudo-file '+' treats the sampled points as column 1, and allows
 additional column values to be specified via a `using` specification, just as
 for a true input file. The number of samples is controlled via `set samples`.
 By default samples are generated over the range given by `set trange`, or if
 trange has not been set than over the full range of `set xrange`.

Note: The use of trange is a change from previous gnuplot versions. It allows
 the sampling range to differ from the x axis range.

plot '+' using ($1):(sin($1)):(sin($1)**2) with filledcurves

An independent sampling range can be provided immediately before the '+'. As
 in normal function plots, a name can be assigned to the independent variable.
 If given for the first plot element, the sampling range specifier has to be
 preceded by the `sample` keyword (see also `plot sampling`).

plot sample [beta=0:2*pi] '+' using (sin(beta)):(cos(beta)) with lines

Additionally, the range specifier of '+' supports giving a sampling increment.

plot $MYDATA, [t=-3:25:1] '+' using (t):(f(t))

The pseudo-file '++' returns 2 columns of data forming a regular grid of [u,v]
 coordinates with the number of points along u controlled by `set samples` and
 the number of points along v controlled by `set isosamples`.  You must set
 urange and vrange before plotting '++'.  However the x and y ranges can be
 autoscaled or can be explicitly set to different values than urange and vrange.
 Use of u and v to sample '++' is a CHANGE introduced in version 5.2
 Examples:

splot '++' using 1:2:(sin($1)*sin($2)) with pm3d
       plot '++' using 1:2:(sin($1)*sin($2)) with image

The special filename `'-'` specifies that the data are inline; i.e., they
 follow the command.  Only the data follow the command; `plot` options like
 filters, titles, and line styles remain on the `plot` command line.  This is
 similar to << in unix shell script, and $DECK in VMS DCL.  The data are
 entered as though they are being read from a file, one data point per record.
 The letter "e" at the start of the first column terminates data entry.

`'-'` is intended for situations where it is useful to have data and commands
 together, e.g. when both are piped to `gnuplot` from another application.
 Some of the demos, for example, might use this feature.  While
 `plot` options such as `index` and `every` are recognized, their use forces
 you to enter data that won't be used.  For all but the simplest cases it is
 probably easier to first define a datablock and then read from it rather than
 from `'-'`.  See `datablocks`.

If you use `'-'` with `replot`, you may need to enter the data more than once.
 See `replot`, `refresh`.  Here again it may be better to use a datablock.

A blank filename ('') specifies that the previous filename should be reused.
 This can be useful with things like

plot 'a/very/long/filename' using 1:2, '' using 1:3, '' using 1:4

(If you use both `'-'` and `''` on the same `plot` command, you'll need to
 have two sets of inline data, as in the example above.)

?commands plot datafile piped-data
?plot datafile piped-data
?datafile piped-data
?plot piped-data
?piped-data
?pipes
 On systems with a popen function, the datafile can be piped through a shell
 command by starting the file name with a '<'.  For example,

pop(x) = 103*exp(-x/10)
       plot "< awk '{print $1-1965, $2}' population.dat", pop(x)

would plot the same information as the first population example but with
 years since 1965 as the x axis.  If you want to execute this example, you
 have to delete all comments from the data file above or substitute the
 following command for the first part of the command above (the part up to
 the comma):

plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' population.dat"

While this approach is most flexible, it is possible to achieve simple
 filtering with the `using` keyword.

On systems with an fdopen() function, data can be read from an arbitrary file
 descriptor attached to either a file or pipe.  To read from file descriptor
 `n` use `'<&n'`.  This allows you to easily pipe in several data files in a
 single call from a POSIX shell:

$ gnuplot -p -e "plot '<&3', '<&4'" 3<data-3 4<data-4
       $ ./gnuplot 5< <(myprogram -with -options)
       gnuplot> plot '<&5'

?commands plot datafile using
?plot datafile using
?plot using
?data-file using
?datafile using
?using
 The most common datafile modifier is `using`.  It tells the program which
 columns of data in the input file are to be plotted.

Syntax:
       plot 'file' using <entry> {:<entry> {:<entry> ...}} {'format'}

If a format is specified, it is used to read in each datafile record using the
 C library 'scanf' function.  Otherwise the record is interpreted as consisting
 of columns (fields) of data separated by whitespace (spaces and/or tabs),
 but see `datafile separator`.

Each <entry> may be a simple column number that selects the value from one
 field of the input file, a string that matches a column label in the first
 line of a data set, an expression enclosed in parentheses, or a special
 function not enclosed in parentheses such as xticlabels(2).

If the entry is an expression in parentheses, then the function column(N) may
 be used to indicate the value in column N. That is, column(1) refers to the
 first item read, column(2) to the second, and so on.  The special symbols
 $1, $2, ... are shorthand for column(1), column(2) ...

The special symbol $# evaluates to the total number of columns in the current
 line of input, so column($#) or stringcolumn($#) always returns the content of
 the final column even if the number of columns is unknown or different lines
 in the file contain different numbers of columns.

The function `valid(N)` tests whether column N contains a valid number.
 If each column of data in the input file contains a label in the first row
 rather than a data value, this label can be used to identify the column on
 input and/or in the plot legend. The column() function can be used to select
 an input column by label rather than by column number.  For example,
 if the data file contains
       Height    Weight    Age
       val1      val1      val1
       ...       ...       ...
 then the following plot commands are all equivalent
       plot 'datafile' using 3:1, '' using 3:2
       plot 'datafile' using (column("Age")):(column(1)), \
                    '' using (column("Age")):(column(2))
       plot 'datafile' using "Age":"Height", '' using "Age":"Weight"

The full string must match. Comparison is case-sensitive.
 To use column labels in the plot legend, use `set key autotitle columnhead`.

In addition to the actual columns 1...N in the input data file, gnuplot
 presents data from several "pseudo-columns" that hold bookkeeping information.
 E.g. $0 or column(0) returns the sequence number of this data record within a
 dataset.  Please see `pseudocolumns`.

An empty <entry> will default to its order in the list of entries.
 For example, `using ::4` is interpreted as `using 1:2:4`.

If the `using` list has only a single entry, that <entry> will be used for y
 and the data point number (pseudo-column $0) is used for x; for example,
 "`plot 'file' using 1`" is identical to "`plot 'file' using 0:1`".
 If the `using` list has two entries, these will be used for x and y.
 See `set style` and `fit` for details about plotting styles that make use of
 data from additional columns of input.

'scanf' accepts several numerical specifications but `gnuplot`
 requires all inputs to be double-precision floating-point variables,
 so "%lf" is essentially the only permissible specifier.
 A format string given by the user must contain at least one such
 input specifier, and no more than seven of them.
 'scanf' expects to see white space---a blank, tab
 ("\t"), newline ("\n"), or formfeed ("\f")---between numbers; anything else
 in the input stream must be explicitly skipped.

Note that the use of "\t", "\n", or "\f" requires use of double-quotes
 rather than single-quotes.
?commands plot datafile using examples
?plot datafile using examples
?datafile using examples
?using examples
 This creates a plot of the sum of the 2nd and 3rd data against the first:
 The format string specifies comma- rather than space-separated columns.
 The same result could be achieved by specifying `set datafile separator comma`.
       plot 'file' using 1:($2+$3) '%lf,%lf,%lf'

In this example the data are read from the file "MyData" using a more
 complicated format:
       plot 'MyData' using "%*lf%lf%*20[^\n]%lf"

The meaning of this format is:

%*lf        ignore a number
       %lf         read a double-precision number (x by default)
       %*20[^\n]   ignore 20 non-newline characters
       %lf         read a double-precision number (y by default)

One trick is to use the ternary `?:` operator to filter data:

plot 'file' using 1:($3>10 ? $2 : 1/0)

which plots the datum in column two against that in column one provided
 the datum in column three exceeds ten.  `1/0` is undefined; `gnuplot`
 quietly ignores undefined points, so unsuitable points are suppressed.
 Or you can use the pre-defined variable NaN to achieve the same result.

In fact, you can use a constant expression for the column number, provided it
 doesn't start with an opening parenthesis; constructs like `using
 0+(complicated expression)` can be used.  The crucial point is that the
 expression is evaluated once if it doesn't start with a left parenthesis, or
 once for each data point read if it does.

If timeseries data are being used, the time can span multiple columns.  The
 starting column should be specified.  Note that the spaces within the time
 must be included when calculating starting columns for other data.  E.g., if
 the first element on a line is a time with an embedded space, the y value
 should be specified as column three.

It should be noted that (a) `plot 'file'`, (b) `plot 'file' using 1:2`, and
 (c) `plot 'file' using ($1):($2)` can be subtly different.  The exact
 behaviour has changed in version 5.  See `missing`.

It is often possible to plot a file with lots of lines of garbage at
 the top simply by specifying

plot 'file' using 1:2

However, if you want to leave text in your data files, it is safer to put the
 comment character (#) in the first column of the text lines.
?pseudocolumns
?commands plot datafile using pseudocolumns
?plot datafile using pseudocolumns
?datafile using pseudocolumns
?using pseudocolumns
 Expressions in the `using` clause of a plot statement can refer to additional
 bookkeeping values in addition to the actual data values contained in the input
 file. These are contained in "pseudocolumns".
       column(0)   The sequential order of each point within a data set.
                   The counter starts at 0, increments on each non-blank,
                   non-comment line, and is reset by two sequential blank
                   records.  The shorthand form $0 is available.
       column(-1)  This counter starts at 0, increments on a single blank line,
                   and is reset by two sequential blank lines.
                   This corresponds to the data line in array or grid data.
                   It can also be used to distinguish separate line segments
                   or polygons within a data set.
       column(-2)  Starts at 0 and increments on two sequential blank lines.
                   This is the index number of the current data set within a
                   file that contains multiple data sets.  See `index`.
       column($#)  The special symbol $# evaluates to the total number of
                   columns available, so column($#) refers to the last
                   (rightmost) field in the current input line.
                   column($# - 1) would refer to the last-but-one column, etc.
?using key
?plot using key
 The layout of certain plot styles (column-stacked histograms, spider plots) 
 is such that it would make no sense to generate plot titles from a data column
 header. Also it would make no sense to generate axis tic labels from the
 content of a data column (e.g. `using 2:3:xticlabels(1)`).  These plots styles
 instead use the form `using 2:3:key(1)` to generate plot titles for the key
 from the text content of a data column, usually a first column of row headers.
 See the example given for `spiderplot`.
?xticlabels
?using xticlabels
?plot using xticlabels
 Axis tick labels can be generated via a string function, usually taking a data
 column as an argument. The simplest form uses the data column itself as a
 string. That is,  xticlabels(N) is shorthand for xticlabels(stringcolumn(N)).
 This example uses the contents of column 3 as x-axis tick labels.

plot 'datafile' using <xcol>:<ycol>:xticlabels(3) with <plotstyle>

Axis tick labels may be generated for any of the plot axes: x x2 y y2 z.
 The `ticlabels(<labelcol>)` specifiers must come after all of the data
 coordinate specifiers in the `using` portion of the command.
 For each data point which has a valid set of X,Y[,Z] coordinates,
 the string value given to xticlabels() is added to the list of xtic labels
 at the same X coordinate as the point it belongs to. `xticlabels()`
 may be shortened to `xtic()` and so on.

Example:

splot "data" using 2:4:6:xtic(1):ytic(3):ztic(6)

In this example the x and y axis tic labels are taken from different columns
 than the x and y coordinate values. The z axis tics, however, are generated
 from the z coordinate of the corresponding point.

Example:

plot "data" using 1:2:xtic( $3 > 10. ? "A" : "B" )

This example shows the use of a string-valued function to generate x-axis
 tick labels. Each point in the data file generates a tick mark on x labeled
 either "A" or "B" depending on the value in column 3.
?using x2ticlabels
?plot using x2ticlabels
 See `plot using xticlabels`.
?using yticlabels
?plot using yticlabels
 See `plot using xticlabels`.
?using y2ticlabels
?plot using y2ticlabels
 See `plot using xticlabels`.
?using zticlabels
?plot using zticlabels
 See `plot using xticlabels`.
?using cbticlabels
 EXPERIMENTAL (details may change in a future release version)
 2D plots: colorbar labels are placed at the palette coordinate used by the
 plot for variable coloring "lc palette z".
 3D plots: colorbar labels are placed at the z coordinate of the point.
 Note that in the case of a 3D heat map with variable color that does not
 match z, this is probably not the correct label.
 See also `plot using xticlabels`.
?datafile volatile
?data volatile
?plot datafile volatile
?plot volatile
?volatile
 The `volatile` keyword in a plot command indicates that the data previously
 read from the input stream or file may not be available for re-reading.
 This tells the program to use `refresh` rather than `replot` commands whenever
 possible.  See `refresh`.
?commands plot errorbars
?commands splot errorbars
?plot errorbars
?splot errorbars
 Error bars are supported for 2D data file plots by reading one to four
 additional columns (or `using` entries); these additional values are used in
 different ways by the various errorbar styles.

In the default situation, `gnuplot` expects to see three, four, or six
 numbers on each line of the data file---either

(x, y, ydelta),
       (x, y, ylow, yhigh),
       (x, y, xdelta),
       (x, y, xlow, xhigh),
       (x, y, xdelta, ydelta), or
       (x, y, xlow, xhigh, ylow, yhigh).

The x coordinate must be specified.  The order of the numbers must be
 exactly as given above, though the `using` qualifier can manipulate the order
 and provide values for missing columns.  For example,

plot 'file' with errorbars
       plot 'file' using 1:2:(sqrt($1)) with xerrorbars
       plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars

The last example is for a file containing an unsupported combination of
 relative x and absolute y errors.  The `using` entry generates absolute x min
 and max from the relative error.

The y error bar is a vertical line plotted from (x, ylow) to (x,
 yhigh). If ydelta is specified instead of ylow and yhigh, ylow = y -
 ydelta and yhigh = y + ydelta are derived. If there are only two
 numbers on the record, yhigh and ylow are both set to y. The x error
 bar is a horizontal line computed in the same fashion. To get lines
 plotted between the data points, `plot` the data file twice, once with
 errorbars and once with lines (but remember to use the `notitle`
 option on one to avoid two entries in the key). Alternately, use the
 errorlines command (see `errorlines`).

The tic marks at the ends of the bar are controlled by `set errorbars`.

If autoscaling is on, the ranges will be adjusted to include the error bars.

See also `splot datafile`.

See also
 contours demo (contours.dem)
 and
 contours with user defined levels demo (discrete.dem).
?commands set dashtype
?commands show dashtype
?set dashtype
?show dashtype
 The `set dashtype` command allows you to define a dash pattern that can
 then be referred to by its index.  This is purely a convenience, as anywhere
 that would accept the dashtype by its numerical index would also accept an
 explicit dash pattern.
 Example:
      set dashtype 5 (2,4,2,6)   # define or redefine dashtype number 5
      plot f1(x) dt 5            # plot using the new dashtype
      plot f1(x) dt (2,4,2,6)    # exactly the same plot as above
      set linetype 5 dt 5        # always use this dash pattern with linetype 5
      set dashtype 66 "..-"      # define a new dashtype using a string
 See also `dashtype`.
?set data style
 This form of the command is deprecated. Please see `set style data`.
?set datafile
?show datafile
 The `set datafile` command options control interpretation of fields read from
 input data files by the `plot`, `splot`, and `fit` commands.
 Several options are currently implemented.
?set datafile columnheaders
 The `set datafile columnheaders` command guarantees that the first row of
 input will be interpreted as column headers rather than as data values.
 It affects all input data sources to plot, splot, fit, and stats commands.
 If this setting is disabled by `unset datafile columnheaders`, the same
 effect is triggered on a per-file basis if there is an explicit columnheader()
 function in a using specifier or plot title associated with that file.
 See also `set key autotitle` and `columnheader`.
?set datafile fortran
?show datafile fortran
?fortran
 The `set datafile fortran` command enables a special check for values in the
 input file expressed as Fortran D or Q constants. This extra check slows down
 the input process, and should only be selected if you do in fact have datafiles
 containing Fortran D or Q constants. The option can be disabled again using
 `unset datafile fortran`.
?set datafile nofpe_trap
?fpe_trap
?nofpe_trap
 The `set datafile nofpe_trap` command tells gnuplot not to re-initialize a
 floating point exception handler before every expression evaluation used while
 reading data from an input file.  This can significantly speed data input from
 very large files at the risk of program termination if a floating-point
 exception is generated.
?set datafile missing
?show datafile missing
?set missing
?missing
 Syntax:
       set datafile missing "<string>"
       set datafile missing NaN
       show datafile missing
       unset datafile

The `set datafile missing` command tells `gnuplot` there is a special string
 used in input data files to denote a missing data entry.  There is no default
 character for `missing`.  Gnuplot makes a distinction between missing data and
 invalid data (e.g. "NaN", 1/0.).  For example invalid data causes a gap in a
 line drawn through sequential data points; missing data does not.

Non-numeric characters found in a numeric field will usually be interpreted as
 invalid rather than as a missing data point unless they happen to match the
 `missing` string.

Conversely `set datafile missing NaN` causes all data or expressions evaluating
 to not-a-number (NaN) to be treated as missing data.

The example below shows differences between gnuplot version 4 and version 5.
 Example:
       set style data linespoints
       plot '-' title "(a)"
          1 10
          2 20
          3 ?
          4 40
          5 50
          e
       set datafile missing "?"
       plot '-' title "(b)"
          1 10
          2 20
          3 ?
          4 40
          5 50
          e
       plot '-' using 1:2 title "(c)"
          1 10
          2 20
          3 NaN
          4 40
          5 50
          e
       plot '-' using 1:($2) title "(d)"
          1 10
          2 20
          3 NaN
          4 40
          5 50
          e

Plot (a) differs in gnuplot 4 and gnuplot 5 because the third line contains
 only one valid number.  Version 4 switched to a single-datum-on-a-line
 convention that the line number is "x" and the datum is "y", erroneously
 placing the point at(2,3).

Both the old and new gnuplot versions handle the same data correctly if the
 '?' character is designated as a marker for missing data (b).

Old gnuplot versions handled NaN differently depending of the form of the
 `using` clause, as shown in plots (c) and (d).  Gnuplot now handles NaN the
 same whether the input column was specified as N or ($N).  See also the
 imageNaN demo.
 Similarly gnuplot 5.4 will notice the missing value flag in column N whether
 the plot command specifies `using N` or `using ($N)` or `using (func($N))`.
 However if the "missing" value is encountered during evaluation of some more
 complicated expression, e.g. `using (column(strcol(1))`, it may evaluate to
 NaN and be treated as invalid data rather than as a missing data point.
 If you nevertheless want to treat this as missing data, use the command
 `set datafile missing NaN`.
?set datafile separator
?show datafile separator
?datafile separator
?separator
 The command `set datafile separator` tells `gnuplot` that data fields in
 subsequent input files are separated by a specific character rather than by
 whitespace.  The most common use is to read in csv (comma-separated value)
 files written by spreadsheet or database programs. By default data fields
 are separated by whitespace.

Syntax:
       set datafile separator {whitespace | tab | comma | "<chars>"}

Examples:
       # Input file contains tab-separated fields
       set datafile separator "\t"

# Input file contains comma-separated values fields
       set datafile separator comma

# Input file contains fields separated by either * or |
       set datafile separator "*|"
?set datafile commentschars
?commentschars
 The command `set datafile commentschars` specifies what characters can be used
 in a data file to begin comment lines. If the first non-blank character on a
 line is one of these characters then the rest of the data line is ignored.
 Default value of the string is "#!" on VMS and "#" otherwise.

Syntax:
       set datafile commentschars {"<string>"}
       show datafile commentschars
       unset commentschars

Then, the following line in a data file is completely ignored
     # 1 2 3 4
 but the following
     1 # 3 4
 will be interpreted as garbage in the 2nd column followed by valid data in
 the 3rd and 4th columns.

Example:
       set datafile commentschars "#!%"
?set datafile binary
 The `set datafile binary` command is used to set the defaults when reading
 binary data files.  The syntax matches precisely that used for commands
 `plot` and `splot`.  See `binary matrix` and `binary general` for details
 about the keywords that can be present in <binary list>.

Syntax:
       set datafile binary <binary list>
       show datafile binary
       show datafile
       unset datafile

Examples:
       set datafile binary filetype=auto
       set datafile binary array=(512,512) format="%uchar"

?show datafile binary
       show datafile binary   # list current settings
?commands set decimalsign
?commands show decimalsign
?commands unset decimalsign
?set decimalsign
?show decimalsign
?unset decimalsign
?decimalsign
 The `set decimalsign` command selects a decimal sign for numbers printed
 into tic labels or `set label` strings.

Syntax:
       set decimalsign {<value> | locale {"<locale>"}}
       unset decimalsign
       show decimalsign

The argument <value> is a string to be used in place of the usual
 decimal point. Typical choices include the period, '.', and the comma,
 ',', but others may be useful, too.  If you omit the <value> argument,
 the decimal separator is not modified from the usual default, which is
 a period.  Unsetting decimalsign has the same effect as omitting <value>.

Example:

Correct typesetting in most European countries requires:
       set decimalsign ','

Please note: If you set an explicit string, this affects only numbers that
 are printed using gnuplot's gprintf() formatting routine, including axis tics.
 It does not affect the format expected for input data, and it does not affect
 numbers printed with the sprintf() formatting routine. To change the behavior
 of both input and output formatting, instead use the form

set decimalsign locale

This instructs the program to use both input and output formats in accordance
 with the current setting of the LC_ALL, LC_NUMERIC, or LANG environmental
 variables.

set decimalsign locale "foo"

This instructs the program to format all input and output in accordance with
 locale "foo", which must be installed.  If locale "foo" is not found then an
 error message is printed and the decimal sign setting is unchanged.
 On linux systems you can get a list of the locales installed on your machine by
 typing "locale -a". A typical linux locale string is of the form "sl_SI.UTF-8".
 A typical Windows locale string is of the form "Slovenian_Slovenia.1250" or
 "slovenian". Please note that interpretation of the locale settings is done by
 the C library at runtime. Older C libraries may offer only partial support for
 locale settings such as the thousands grouping separator character.

set decimalsign locale; set decimalsign "."

This sets all input and output to use whatever decimal sign is correct for
 the current locale, but over-rides this with an explicit '.' in numbers
 formatted using gnuplot's internal gprintf() function.
?commands set dgrid3d
?commands unset dgrid3d
?commands show dgrid3d
?set dgrid3d
?unset dgrid3d
?show dgrid3d
?dgrid3d
?nodgrid3d
 The `set dgrid3d` command enables, and can set parameters for, non-grid to
 grid data mapping.  See `splot grid_data` for more details about the grid data
 structure.

Syntax:
       set dgrid3d {<rows>} {,{<cols>}}
                   { splines |
                     qnorm {<norm>} |
                     (gauss | cauchy | exp | box | hann)
                       {kdensity} {<dx>} {,<dy>} }
       unset dgrid3d
       show dgrid3d

By default `dgrid3d` is disabled.  When enabled, 3D data read from a file
 are always treated as a scattered data set.  A grid with dimensions derived
 from a bounding box of the scattered data and size as specified by the
 row/col_size parameters is created for plotting and contouring.  The grid
 is equally spaced in x (rows) and in y (columns); the z values are computed
 as weighted averages or spline interpolations of the scattered points' z
 values. In other words, a regularly spaced grid is created and the a smooth
 approximation to the raw data is evaluated for all grid points. This
 approximation is plotted in place of the raw data.

The number of columns defaults to the number of rows, which defaults to 10.

Several algorithms are available to calculate the approximation from the
 raw data. Some of these algorithms can take additional parameters.
 These interpolations are such the closer the data point is to a grid point,
 the more effect it has on that grid point.

The `splines` algorithm calculates an interpolation based on "thin plate
 splines". It does not take additional parameters.

The `qnorm` algorithm calculates a weighted average of the input data at
 each grid point. Each data point is weighted by the inverse of its distance
 from the grid point raised to some power. The power is specified as an
 optional integer parameter that defaults to 1.
 This algorithm is the default.

Finally, several smoothing kernels are available to calculate weighted
 averages: z = Sum_i w(d_i) * z_i / Sum_i w(d_i), where z_i is the value
 of the i-th data point and d_i is the distance between the current grid
 point and the location of the i-th data point. All kernels assign higher
 weights to data points that are close to the current grid point and lower
 weights to data points further away.

The following kernels are available:
       gauss :     w(d) = exp(-d*d)
       cauchy :    w(d) = 1/(1 + d*d)
       exp :       w(d) = exp(-d)
       box :       w(d) = 1                     if d<1
                        = 0                     otherwise
       hann :      w(d) = 0.5*(1+cos(pi*d))     if d<1
                   w(d) = 0                     otherwise

When using one of these five smoothing kernels, up to two additional
 numerical parameters can be specified: dx and dy. These are used to
 rescale the coordinate differences when calculating the distance:
 d_i = sqrt( ((x-x_i)/dx)**2 + ((y-y_i)/dy)**2 ), where x,y are the
 coordinates of the current grid point and x_i,y_i are the coordinates
 of the i-th data point. The value of dy defaults to the value of dx,
 which defaults to 1. The parameters dx and dy make it possible to
 control the radius over which data points contribute to a grid point
 IN THE UNITS OF THE DATA ITSELF.

The optional keyword `kdensity`, which must come after the name of the
 kernel, but before the (optional) scale parameters, modifies the algorithm
 so that the values calculated for the grid points are not divided by the
 sum of the weights ( z = Sum_i w(d_i) * z_i ). If all z_i are constant,
 this effectively plots a bivariate kernel density estimate: a kernel
 function (one of the five defined above) is placed at each data point,
 the sum of these kernels is evaluated at every grid point, and this smooth
 surface is plotted instead of the original data. This is similar in
 principle to + what the `smooth kdensity` option does to 1D datasets.
 (See kdensity2d.dem for usage demo)

A slightly different syntax is also supported for reasons of backwards
 compatibility. If no interpolation algorithm has been explicitly selected,
 the `qnorm` algorithm is assumed. Up to three comma-separated, optional
 parameters can be specified, which are interpreted as the the number of
 rows, the number of columns, and the norm value, respectively.

The `dgrid3d` option is a simple scheme which replaces scattered data
 with weighted averages on a regular grid.  More sophisticated approaches
 to this problem exist and should be used to preprocess the data outside
 `gnuplot` if this simple solution is found inadequate.

See also
 dgrid3d.dem: dgrid3d demo.
 and
 scatter.dem: dgrid3d demo.

?commands set dummy
?commands show dummy
?set dummy
?show dummy
?unset dummy
?dummy
 The `set dummy` command changes the default dummy variable names.

Syntax:
       set dummy {<dummy-var>} {,<dummy-var>}
       show dummy

By default, `gnuplot` assumes that the independent, or "dummy", variable for
 the `plot` command is "t" if in parametric or polar mode, or "x" otherwise.
 Similarly the independent variables for the `splot` command are "u" and "v"
 in parametric mode (`splot` cannot be used in polar mode), or "x" and "y"
 otherwise.

It may be more convenient to call a dummy variable by a more physically
 meaningful or conventional name.  For example, when plotting time functions:

set dummy t
       plot sin(t), cos(t)

Examples:
       set dummy u,v
       set dummy ,s

The second example sets the second variable to s.  To reset the dummy variable
 names to their default values, use

unset dummy
?commands set encoding
?commands show encoding
?set encoding
?show encoding
?encoding
?encodings
?utf8
?sjis
 The `set encoding` command selects a character encoding.

Syntax:
       set encoding {<value>}
       set encoding locale
       show encoding

Valid values are
    default     - tells a terminal to use its default encoding
    iso_8859_1  - the most common Western European encoding prior to UTF-8.
                  Known in the PostScript world as 'ISO-Latin1'.
    iso_8859_15 - a variant of iso_8859_1 that includes the Euro symbol
    iso_8859_2  - used in Central and Eastern Europe
    iso_8859_9  - used in Turkey (also known as Latin5)
    koi8r       - popular Unix cyrillic encoding
    koi8u       - Ukrainian Unix cyrillic encoding
    cp437       - codepage for MS-DOS
    cp850       - codepage for OS/2, Western Europe
    cp852       - codepage for OS/2, Central and Eastern Europe
    cp950       - MS version of Big5 (emf terminal only)
    cp1250      - codepage for MS Windows, Central and Eastern Europe
    cp1251      - codepage for 8-bit Russian, Serbian, Bulgarian, Macedonian
    cp1252      - codepage for MS Windows, Western Europe
    cp1254      - codepage for MS Windows, Turkish (superset of Latin5)
    sjis        - shift-JIS Japanese encoding
    utf8        - variable-length (multibyte) representation of Unicode
                  entry point for each character

The command `set encoding locale` is different from the other options.
 It attempts to determine the current locale from the runtime environment.
 On most systems this is controlled by the environmental variables
 LC_ALL, LC_CTYPE, or LANG.  This mechanism is necessary, for example, to
 pass multibyte character encodings such as UTF-8 or EUC_JP to the wxt
 and pdf terminals.  This command does not affect the locale-specific
 representation of dates or numbers.
 See also `set locale` and `set decimalsign`.

Generally you must set the encoding before setting the terminal type, as it
 may affect the choice of appropriate fonts.
?commands set errorbars
?commands show errorbars
?set errorbars
?show errorbars
?errorbars
?commands set bars
?commands show bars
?set bars
?show bars
?bars
 The `set errorbars` command controls the tics at the ends of error bars,
 and also at the end of the whiskers belonging to a boxplot.

Syntax:
       set errorbars {small | large | fullwidth | <size>} {front | back}
                     {line-properties}
       unset errorbars
       show errorbars

`small` is a synonym for 0.0 (no crossbar), and `large` for 1.0.
 The default is 1.0 if no size is given.

The keyword `fullwidth` is relevant only to boxplots and to histograms with
 errorbars.  It sets the width of the errorbar ends to be the same as the width
 of the associated box.  It does not change the width of the box itself.

The `front` and `back` keywords are relevant only to errorbars attached
 to filled rectangles (boxes, candlesticks, histograms).

Error bars are by default drawn using the same line properties as the border
 of the associated box. You can change this by providing a separate set of
 line properties for the error bars.

set errorbars linecolor black linewidth 0.5 dashtype '.'
?commands set fit
?commands show fit
?set fit
?show fit
?set fit quiet
?set fit verbose
?set fit brief
?set fit results
?set fit prescale
?set fit limit
?set fit maxiter
?set fit errorscaling
?set fit errorvariables
?set fit logfile
?set fit script
?set fit v4
?set fit v5
 The `set fit` command controls the options for the `fit` command.

Syntax:
       set fit {nolog | logfile {"<filename>"|default}}
               {{no}quiet|results|brief|verbose}
               {{no}errorvariables}
               {{no}covariancevariables}
               {{no}errorscaling}
               {{no}prescale}
               {maxiter <value>|default}
               {limit <epsilon>|default}
               {limit_abs <epsilon_abs>}
               {start-lambda <value>|default}
               {lambda-factor <value>|default}
               {script {"<command>"|default}}
               {v4 | v5}
       unset fit
       show fit

The `logfile` option defines where the `fit` command writes its output.  The
 <filename> argument must be enclosed in single or double quotes.  If no
 filename is given or `unset fit` is used the log file is reset to its default
 value "fit.log" or the value of the environmental variable `FIT_LOG`.  If the
 given logfile name ends with a / or \, it is interpreted to be a directory
 name, and the actual filename will be "fit.log" in that directory.

By default the information written to the log file is also echoed to the
 terminal session.  `set fit quiet` turns off the echo, whereas `results`
 prints only final results.  `brief` gives one line summaries for every
 iteration of the fit in addition.  `verbose` yields detailed iteration
 reports as in version 4.

If the `errorvariables` option is turned on, the error of each fitted
 parameter computed by `fit` will be copied to a user-defined variable
 whose name is formed by appending "_err" to the name of the parameter
 itself.  This is useful mainly to put the parameter and its error onto
 a plot of the data and the fitted function, for reference, as in:

set fit errorvariables
        fit f(x) 'datafile' using 1:2 via a, b
        print "error of a is:", a_err
        set label 1 sprintf("a=%6.2f +/- %6.2f", a, a_err)
        plot 'datafile' using 1:2, f(x)

If the `errorscaling` option is specified, which is the default, the
 calculated parameter errors are scaled with the reduced chi square.  This is
 equivalent to providing data errors equal to the calculated standard
 deviation of the fit (FIT_STDFIT) resulting in a reduced chi square of one.
 With the `noerrorscaling` option the estimated errors are the unscaled
 standard deviations of the fit parameters.
 If no weights are specified for the data, parameter errors are always scaled.

If the `prescale` option is turned on, parameters are prescaled by their
 initial values before being passed to the Marquardt-Levenberg
 routine. This helps tremendously if there are parameters that differ
 in size by many orders of magnitude. Fit parameters with an initial value
 of exactly zero are never prescaled.

The maximum number of iterations may be limited with the `maxiter` option.
 A value of 0 or `default` means that there is no limit.

The `limit` option can be used to change the default epsilon limit (1e-5) to
 detect convergence.  When the sum of squared residuals changes by a factor
 less than this number (epsilon), the fit is considered to have 'converged'.
 The `limit_abs` option imposes an additional absolute limit in the change
 of the sum of squared residuals and defaults to zero.

If you need even more control about the algorithm, and know the
 Marquardt-Levenberg algorithm well, the following options can be used to
 influence it. The startup value of `lambda` is normally calculated
 automatically from the ML-matrix, but if you want to, you may provide your
 own using the `start_lambda` option. Setting it to `default` will
 re-enable the automatic selection. The option `lambda_factor` sets the factor
 by which `lambda` is increased or decreased whenever the chi-squared target
 function increased or decreased significantly. Setting it to `default`
 re-enables the default factor of 10.0.

The `script` option may be used to specify a `gnuplot` command to be executed
 when a fit is interrupted---see `fit`.  This setting takes precedence over
 the default of `replot` and the environment variable `FIT_SCRIPT`.

If the `covariancevariables` option is turned on, the covariances between
 final parameters will be saved to user-defined variables. The variable name
 for a certain parameter combination is formed by prepending "FIT_COV_" to
 the name of the first parameter and combining the two parameter names by
 "_". For example given the parameters "a" and "b" the covariance variable is
 named "FIT_COV_a_b".

In version 5 the syntax of the fit command changed and it now defaults to
 unitweights if no 'error' keyword is given.  The `v4` option restores the
 default behavior of gnuplot version 4, see also `fit`.
?commands set fontpath
?commands show fontpath
?set fontpath
?show fontpath
?fontpath
 Syntax:
       set fontpath "/directory/where/my/fonts/live"
       set term postscript fontfile <filename>

[DEPRECATED in version 5.4]

The `fontpath` directory is relevant only for embedding fonts in
 postscript output produced by the postscript terminal.
 It has no effect on other gnuplot terminals.
 If you are not embedding fonts you do not need this command, and even if you
 are embedding fonts you only need it for fonts that cannot be found via
 the other paths below.

Earlier versions of gnuplot tried to emulate a font manager by tracking
 multiple directory trees containing fonts.
 This is now replaced by a search in the following places:
 (1) an absolute path given in the `set term postscript fontfile` command
 (2) the current directory
 (3) any of the directories specified by `set loadpath`
 (4) the directory specified by `set fontpath`
 (5) the directory provided in environmental variable GNUPLOT_FONTPATH

Note: The search path for fonts specified by filename for the libgd terminals
 (png gif jpeg sixel) is controlled by environmental variable GDFONTPATH.
?commands set format
?commands show format
?set format
?show format
?format
?format cb
 The format of the tic-mark labels can be set with the `set format` command
 or with the `set tics format` or individual `set {axis}tics format` commands.

Syntax:
       set format {<axes>} {"<format-string>"} {numeric|timedate|geographic}
       show format

where <axes> is either `x`, `y`, `xy`, `x2`, `y2`, `z`, `cb` or nothing
 (which applies the format to all axes). The following two commands are
 equivalent:
       set format y "%.2f"
       set ytics format "%.2f"

The length of the string is restricted to 100 characters.  The default format
 is "% h", "$%h$" for LaTeX terminals. Other formats such as "%.2f" or "%3.0em"
 are often desirable. "set format" with no following string will restore the
 default.

If the empty string "" is given, tics will have no labels, although the tic
 mark will still be plotted.  To eliminate the tic marks, use `unset xtics` or
 `set tics scale 0`.

Newline (\n) and enhanced text markup is accepted in the format string.
 Use double-quotes rather than single-quotes in this case.  See also `syntax`.
 Characters not preceded by "%" are printed verbatim.  Thus you can include
 spaces and labels in your format string, such as "%g m", which will put " m"
 after each number.  If you want "%" itself, double it: "%g %%".

See also `set xtics` for more information about tic labels, and
 `set decimalsign` for how to use non-default decimal separators in numbers
 printed this way.
 See also
 electron demo (electron.dem).
?gprintf
 The string function gprintf("format",x) uses gnuplot's own format specifiers,
 as do the gnuplot commands `set format`, `set timestamp`, and others. These
 format specifiers are not the same as those used by the standard C-language
 routine sprintf(). gprintf() accepts only a single variable to be formatted.
 Gnuplot also provides an sprintf("format",x1,x2,...) routine if you prefer.
 For a list of gnuplot's format options, see `format specifiers`.
?commands set format specifiers
?set format specifiers
?format specifiers
?format_specifiers
 The acceptable formats (if not in time/date mode) are:

Format       Explanation
       %f           floating point notation
       %e or %E     exponential notation; an "e" or "E" before the power
       %g or %G     the shorter of %e (or %E) and %f
       %h or %H     like %g with "x10^{%S}" or "*10^{%S}" instead of "e%S"
       %x or %X     hex
       %o or %O     octal
       %t           mantissa to base 10
       %l           mantissa to base of current logscale
       %s           mantissa to base of current logscale; scientific power
       %T           power to base 10
       %L           power to base of current logscale
       %S           scientific power
       %c           character replacement for scientific power
       %b           mantissa of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi)
       %B           prefix of ISO/IEC 80000 notation (ki, Mi, Gi, Ti, Pi, Ei, Zi, Yi)
       %P           multiple of pi

A 'scientific' power is one such that the exponent is a multiple of three.
 Character replacement of scientific powers (`"%c"`) has been implemented
 for powers in the range -18 to +18.  For numbers outside of this range the
 format reverts to exponential.

Other acceptable modifiers (which come after the "%" but before the format
 specifier) are "-", which left-justifies the number; "+", which forces all
 numbers to be explicitly signed; " " (a space), which makes positive numbers
 have a space in front of them where negative numbers have "-";
 "#", which places a decimal point after
 floats that have only zeroes following the decimal point; a positive integer,
 which defines the field width; "0" (the digit, not the letter) immediately
 preceding the field width, which indicates that leading zeroes are to be used
 instead of leading blanks; and a decimal point followed by a non-negative
 integer, which defines the precision (the minimum number of digits of an
 integer, or the number of digits following the decimal point of a float).

Some systems may not support all of these modifiers but may also support
 others; in case of doubt, check the appropriate documentation and
 then experiment.

Examples:
       set format y "%t"; set ytics (5,10)          # "5.0" and "1.0"
       set format y "%s"; set ytics (500,1000)      # "500" and "1.0"
       set format y "%+-12.3f"; set ytics(12345)    # "+12345.000  "
       set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
       set format y "%s*10^{%S}"; set ytic(12345)   # "12.345*10^{3}"
       set format y "%s %cg"; set ytic(12345)       # "12.345 kg"
       set format y "%.0P pi"; set ytic(6.283185)   # "2 pi"
       set format y "%.0f%%"; set ytic(50)          # "50%"

set log y 2; set format y '%l'; set ytics (1,2,3)
       #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)

There are some problem cases that arise when numbers like 9.999 are printed
 with a format that requires both rounding and a power.

If the data type for the axis is time/date, the format string must contain
 valid codes for the 'strftime' function (outside of `gnuplot`, type "man
 strftime").  See `set timefmt` for a list of the allowed input format codes.
?commands set format date_specifiers
?commands set format time_specifiers
?set format date_specifiers
?set format time_specifiers
?set date_specifiers
?set time_specifiers
?date_specifiers
?time_specifiers
 There are two groups of time format specifiers: time/date and relative time.
 These may be used to generate axis tic labels or to encode time in a string.
 See `set xtics time`, `strftime`, `strptime`.

The time/date formats are

Format       Explanation
       %a           short name of day of the week (ignored on input)
       %A           full name of day of the week (ignored on input)
       %b or %h     abbreviated name of the month
       %B           full name of the month
       %d           day of the month, 01--31
       %D           shorthand for "%m/%d/%y" (only output)
       %F           shorthand for "%Y-%m-%d" (only output)
       %k           hour, 0--23 (one or two digits)
       %H           hour, 00--23 (always two digits)
       %l           hour, 1--12 (one or two digits)
       %I           hour, 01--12 (always two digits)
       %j           day of the year, 001--366
       %m           month, 01--12
       %M           minute, 00--60
       %p           "am" or "pm"
       %r           shorthand for "%I:%M:%S %p" (only output)
       %R           shorthand for "%H:%M" (only output)
       %s           number of seconds since the start of year 1970
       %S           second, integer 00--60 on output, (double) on input
       %T           shorthand for "%H:%M:%S" (only output)
       %U           week of the year (CDC/MMWR "epi week") (ignored on input)
       %w           day of the week, 0--6 (Sunday = 0) (ignored on input)
       %W           week of the year (ISO 8601 week date) (ignored on input)
       %y           year, 0-68 for 2000-2068, 69-99 for 1969-1999
       %Y           year, 4-digit
       %z           timezone, [+-]hh:mm
       %Z           timezone name, ignored string

For more information on the %W format (ISO week of year) see `tm_week`.
 The %U format (CDC/MMWR epidemiological week) is similar to %W except that it
 uses weeks that start on Sunday rather than Monday.
 Caveat: Both the %W and the %U formats were unreliable in gnuplot versions
 prior to 5.4.2.  See unit test "week_date.dem".

The relative time formats express the length of a time interval on either
 side of a zero time point.  The relative time formats are

Format       Explanation
       %tD          +/- days relative to time=0
       %tH          +/- hours relative to time=0 (does not wrap at 24)
       %tM          +/- minutes relative to time=0
       %tS          +/- seconds associated with previous tH or tM field

Numerical formats may be preceded by a "0" ("zero") to pad the field with
 leading zeroes, and preceded by a positive digit to define the minimum field
 width.  The %S, and %t formats also accept a precision specifier so that
 fractional hours/minutes/seconds can be written.

?commands set format date_specifiers examples
?commands set format time_specifiers examples
?set format date_specifiers examples
?set format time_specifiers examples
?set date_specifiers examples
?set time_specifiers examples
?date_specifiers examples
?time_specifiers examples

Examples of date format:

Suppose the x value in seconds corresponds a time slightly before midnight
 on 25 Dec 1976. The text printed for a tic label at this position would be

set format x                 # defaults to "12/25/76 \n 23:11"
       set format x "%A, %d %b %Y"  # "Saturday, 25 Dec 1976"
       set format x "%r %D"         # "11:11:11 pm 12/25/76"

Examples of time format:

The date format specifiers encode a time in seconds as a clock time on a
 particular day.  So hours run only from 0-23, minutes from 0-59, and negative
 values correspond to dates prior to the epoch (1-Jan-1970). In order to report
 a time value in seconds as some number of hours/minutes/seconds relative to a
 time 0, use time formats %tH %tM %tS.  To report a value of -3672.50 seconds

set format x                 # default date format "12/31/69 \n 22:58"
       set format x "%tH:%tM:%tS"   # "-01:01:12"
       set format x "%.2tH hours"   # "-1.02 hours"
       set format x "%tM:%.2tS"     # "-61:12.50"

?expressions functions tm_week
?functions tm_week
?time_specifiers tm_week
?tm_week
?epidemiological week
 The `tm_week(t, standard)` function interprets its first argument t as a time
 in seconds from 1 Jan 1970.  Despite the name of this function it does not
 report a field from the POSIX tm structure.

If standard = 0 it returns the week number in the ISO 8601 "week date" system.
 This corresponds to gnuplot's %W time format.
 If standard = 1 it returns the CDC epidemiological week number ("epi week").
 This corresponds to gnuplot's %U time format.
 For corresponding inverse functions that convert week dates to calendar time
 see `weekdate_iso`, `weekdate_cdc`.

In brief, ISO Week 1 of year YYYY begins on the Monday closest to 1 Jan YYYY.
 This may place it in the previous calendar year.  For example Tue 30 Dec 2008
 has ISO week date 2009-W01-2 (2nd day of week 1 of 2009).  Up to three days
 at the start of January may come before the Monday of ISO week 1;
 these days are assigned to the final week of the previous calendar year.
 E.g. Fri 1 Jan 2021 has ISO week date 2020-W53-5.

The US Center for Disease Control (CDC) epidemiological week is a similar
 week date convention that differs from the ISO standard by defining a week as
 starting on Sunday, rather than on Monday.

?expressions functions weekdate_iso
?functions weekdate_iso
?time_specifiers weekdate_iso
?weekdate_iso
 Syntax:
      time = weekdate_iso( year, week [, day] )

This function converts from the year, week, day components of a date in
 ISO 8601 "week date" format to the calendar date as a time in seconds since
 the epoch date 1 Jan 1970.  Note that the nominal year in the week date
 system is not necessarily the same as the calendar year.  The week is an
 integer from 1 to 53.  The day parameter is optional. If it is omitted
 or equal to 0 the time returned is the start of the week. Otherwise day
 is an integer from 1 (Monday) to 7 (Sunday).
 See `tm_week` for additional information on an inverse function that converts
 from calendar date to week number in the ISO standard convention.

Example:
      # Plot data from a file with column 1 containing ISO weeks
      #     Week     cases  deaths
      #     2020-05    432       1
      calendar_date(w) = weekdate_iso( int(w[1:4]), int(w[6:7]) )
      set xtics time format "%b\n%Y"
      plot FILE using (calendar_date(strcol(1))) : 2   title columnhead

?expressions functions weekdate_cdc
?functions weekdate_cdc
?time_specifiers weekdate_cdc
?weekdate_cdc
 Syntax:
      time = weekdate_cdc( year, week [, day] )

This function converts from the year, week, day components of a date in
 the CDC/MMWR "epi week" format to the calendar date as a time in seconds since
 the epoch date 1 Jan 1970.  The CDC week date convention differs from the
 ISO week date in that it is defined in terms of each week running from
 day 1 = Sunday to day 7 = Saturday.  If the third parameter is 0 or is
 omitted, the time returned is the start of the week.
 See `tm_week` and `weekdate_iso`.

?set function style
 This form of the command is deprecated. Please use `set style function`.
?commands show functions
?show functions
 The `show functions` command lists all user-defined functions and their
 definitions.

Syntax:
       show functions

For information about the definition and usage of functions in `gnuplot`,
 please see `expressions`.
 See also
 splines as user defined functions (spline.dem)
 and
 use of functions and complex variables for airfoils (airfoil.dem).

?commands set grid
?commands unset grid
?commands show grid
?set grid
?set grid vertical
?unset grid
?show grid
?grid
?nogrid
 The `set grid` command allows grid lines to be drawn on the plot.

Syntax:
       set grid {{no}{m}xtics} {{no}{m}ytics} {{no}{m}ztics}
                {{no}{m}x2tics} {{no}{m}y2tics} {{no}{m}rtics}
                {{no}{m}cbtics}
                {polar {<angle>}}
                {layerdefault | front | back}
                {{no}vertical}
                {<line-properties-major> {, <line-properties-minor>}}
       unset grid
       show grid

The grid can be enabled and disabled for the major and/or minor tic
 marks on any axis, and the linetype and linewidth can be specified
 for major and minor grid lines, also via a predefined linestyle, as
 far as the active terminal driver supports this (see `set style line`).

A polar grid can be drawn for 2D plots.  This is the default action of
 `set grid` if the program is already in polar mode, but can be enabled
 explicitly by `set grid polar <angle> rtics` whether or not the program is in
 polar mode.  Circles are drawn to intersect major and/or minor tics along the
 r axis, and radial lines are drawn with a spacing of <angle>.  Tic marks
 around the perimeter are controlled by `set ttics`, but these do not produce
 radial grid lines.

The pertinent tics must be enabled before `set grid` can draw them; `gnuplot`
 will quietly ignore instructions to draw grid lines at non-existent tics, but
 they will appear if the tics are subsequently enabled.

If no linetype is specified for the minor gridlines, the same linetype as the
 major gridlines is used.  The default polar angle is 30 degrees.

If `front` is given, the grid is drawn on top of the graphed data. If
 `back` is given, the grid is drawn underneath the graphed data. Using
 `front` will prevent the grid from being obscured by dense data. The
 default setup, `layerdefault`, is equivalent to `back` for 2D plots.
 In 3D plots the default is to split up the grid and the graph box into
 two layers: one behind, the other in front of the plotted data and
 functions. Since `hidden3d` mode does its own sorting, it ignores
 all grid drawing order options and passes the grid lines through the
 hidden line removal machinery instead. These options actually affect
 not only the grid, but also the lines output by `set border` and the
 various ticmarks (see `set xtics`).

In 3D plots grid lines at x- and y- axis tic positions are by default drawn
 only on the base plane parallel to z=0.  The `vertical` keyword activates
 drawing grid lines in the xz and yz planes also, running from zmin to zmax.

Z grid lines are drawn on the bottom of the plot.  This looks better if a
 partial box is drawn around the plot---see `set border`.
?commands set hidden3d
?commands unset hidden3d
?commands show hidden3d
?set hidden3d
?unset hidden3d
?show hidden3d
?hidden3d
?nohidden3d
 The `set hidden3d` command enables hidden line removal for surface plotting
 (see `splot`).  Some optional features of the underlying algorithm can also
 be controlled using this command.

Syntax:
       set hidden3d {defaults} |
                    { {front|back}
                      {{offset <offset>} | {nooffset}}
                      {trianglepattern <bitpattern>}
                      {{undefined <level>} | {noundefined}}
                      {{no}altdiagonal}
                      {{no}bentover} }
       unset hidden3d
       show hidden3d

In contrast to the usual display in gnuplot, hidden line removal actually
 treats the given function or data grids as real surfaces that can't be seen
 through, so plot elements behind the surface will be hidden by it.  For this
 to work, the surface needs to have 'grid structure' (see `splot datafile`
 about this), and it has to be drawn `with lines` or `with linespoints`.

When `hidden3d` is set, both the hidden portion of the surface and possibly
 its contours drawn on the base (see `set contour`) as well as the grid will
 be hidden.  Each surface has its hidden parts removed with respect to itself
 and to other surfaces, if more than one surface is plotted.  Contours drawn
 on the surface (`set contour surface`) don't work.

`hidden3d` also affects 3D plotting styles `points`, `labels`, `vectors`, and
 `impulses` even if no surface is present in the graph.
 Unobscured portions of each vector are drawn as line segments (no arrowheads).
 Individual plots within the graph may be explicitly excluded from this
 processing by appending the extra option `nohidden3d` to the `with` specifier.

Hidden3d does not affect solid surfaces drawn using the pm3d mode. To achieve
 a similar effect purely for pm3d surfaces, use instead `set pm3d depthorder`.
 To mix pm3d surfaces with normal `hidden3d` processing, use the option
 `set hidden3d front` to force all elements included in hidden3d processing to
 be drawn after any remaining plot elements, including the pm3d surface.

Functions are evaluated at isoline intersections.  The algorithm interpolates
 linearly between function points or data points when determining the visible
 line segments.  This means that the appearance of a function may be different
 when plotted with `hidden3d` than when plotted with `nohidden3d` because in
 the latter case functions are evaluated at each sample.  Please see
 `set samples` and `set isosamples` for discussion of the difference.

The algorithm used to remove the hidden parts of the surfaces has some
 additional features controllable by this command.  Specifying `defaults` will
 set them all to their default settings, as detailed below.  If `defaults` is
 not given, only explicitly specified options will be influenced: all others
 will keep their previous values, so you can turn on/off hidden line removal
 via `set {no}hidden3d`, without modifying the set of options you chose.

The first option, `offset`, influences the linetype used for lines on the
 'back' side.  Normally, they are drawn in a linetype one index number higher
 than the one used for the front, to make the two sides of the surface
 distinguishable.  You can specify a different linetype offset to add
 instead of the default 1, by `offset <offset>`.  Option `nooffset` stands for
 `offset 0`, making the two sides of the surface use the same linetype.

Next comes the option `trianglepattern <bitpattern>`.  <bitpattern> must be
 a number between 0 and 7, interpreted as a bit pattern.  Each bit determines
 the visibility of one edge of the triangles each surface is split up into.
 Bit 0 is for the 'horizontal' edges of the grid, Bit 1 for the 'vertical'
 ones, and Bit 2 for the diagonals that split each cell of the original grid
 into two triangles.  The default pattern is 3, making all horizontal and
 vertical lines visible, but not the diagonals.  You may want to choose 7 to
 see those diagonals as well.

The `undefined <level>` option lets you decide what the algorithm is to do
 with data points that are undefined (missing data, or undefined function
 values), or exceed the given x-, y- or z-ranges.  Such points can either be
 plotted nevertheless, or taken out of the input data set.  All surface
 elements touching a point that is taken out will be taken out as well, thus
 creating a hole in the surface.  If <level> = 3, equivalent to option
 `noundefined`, no points will be thrown away at all.  This may produce all
 kinds of problems elsewhere, so you should avoid this.  <level> = 2 will
 throw away undefined points, but keep the out-of-range ones.  <level> = 1,
 the default, will get rid of out-of-range points as well.

By specifying `noaltdiagonal`, you can override the default handling of a
 special case can occur if `undefined` is active (i.e. <level> is not 3).
 Each cell of the grid-structured input surface will be divided in two
 triangles along one of its diagonals.  Normally, all these diagonals have
 the same orientation relative to the grid.  If exactly one of the four cell
 corners is excluded by the `undefined` handler, and this is on the usual
 diagonal, both triangles will be excluded.  However if the default setting
 of `altdiagonal` is active, the other diagonal will be chosen for this cell
 instead, minimizing the size of the hole in the surface.

The `bentover` option controls what happens to another special case, this
 time in conjunction with the `trianglepattern`.  For rather crumply surfaces,
 it can happen that the two triangles a surface cell is divided into are seen
 from opposite sides (i.e. the original quadrangle is 'bent over'), as
 illustrated in the following ASCII art:

C----B
     original quadrangle:  A--B      displayed quadrangle:     |\   |
       ("set view 0,0")    | /|    ("set view 75,75" perhaps)  | \  |
                           |/ |                                |  \ |
                           C--D                                |   \|
                                                               A    D

If the diagonal edges of the surface cells aren't generally made visible by
 bit 2 of the <bitpattern> there, the edge CB above wouldn't be drawn at all,
 normally, making the resulting display hard to understand.  Therefore, the
 default option of `bentover` will turn it visible in this case.  If you don't
 want that, you may choose `nobentover` instead.
 See also
 hidden line removal demo (hidden.dem)
 and
 complex hidden line demo (singulr.dem).
?commands set historysize
?set historysize
?unset historysize
?historysize
 (Deprecated).
 `set historysize N` is equivalent to `set history size N`.
 `unset historysize` is equivalent to `set history size -1`.
?commands set history
?set history
 Syntax:
    set history {size <N>} {quiet|numbers} {full|trim} {default}

When leaving gnuplot the value of history size limits the number of lines
 saved to the history file. `set history size -1` allows an unlimited number
 of lines to be written to the history file.

By default the `history` command prints a line number in front of each command.
 `history quiet` suppresses the number for this command only.
 `set history quiet` suppresses numbers for all future `history` commands.

The `trim` option reduces the number of duplicate lines in the history list
 by removing earlier instances of the current command.

Default settings: `set history size 500 numbers trim`.
?commands set isosamples
?commands show isosamples
?set isosamples
?show isosamples
?isosamples
 The isoline density (grid) for plotting functions as surfaces may be changed
 by the `set isosamples` command.

Syntax:
       set isosamples <iso_1> {,<iso_2>}
       show isosamples

Each function surface plot will have <iso_1> iso-u lines and <iso_2> iso-v
 lines.  If you only specify <iso_1>, <iso_2> will be set to the same value
 as <iso_1>.  By default, sampling is set to 10 isolines per u or v axis.
 A higher sampling rate will produce more accurate plots, but will take longer.
 These parameters have no effect on data file plotting.

An isoline is a curve parameterized by one of the surface parameters while
 the other surface parameter is fixed.  Isolines provide a simple means to
 display a surface.  By fixing the u parameter of surface s(u,v), the iso-u
 lines of the form c(v) = s(u0,v) are produced, and by fixing the v parameter,
 the iso-v lines of the form c(u) = s(u,v0) are produced.

When a function surface plot is being done without the removal of hidden
 lines, `set samples`  controls the number of points sampled along each
 isoline;  see `set samples` and `set hidden3d`. The contour algorithm
 assumes that a function sample occurs at each isoline intersection, so
 change in `samples` as well as `isosamples` may be desired when changing
 the resolution of a function surface/contour.
?commands set isosurface
?commands show isosurface
?set isosurface
?show isosurface
 Syntax:
      set isosurface {mixed|triangles}
      set isosurface {no}insidecolor <n>
 Surfaces plotted by the command `splot $voxelgrid with isosurface` are by
 default constructed from a mixture of quadrangles and triangles.  The use
 of quadrangles creates a less complicated visual impression.  This is the
 default.  This command proveds an option to tessellate with only triangles.

By default the inside of an isosurface is drawn in a separate color.
 The method of choosing that color is the same as for hidden3d surfaces,
 where an offset <n> is added to the base linetype.  To draw both the inside
 and outside surfaces in the same color, use `set isosurface noinsidecolor`.
?commands set jitter
?set jitter
?jitter
 Syntax:
       set jitter {overlap <yposition>} {spread <factor>} {wrap <limit>}
                  {swarm|square|vertical}
 Examples:
       set jitter                    # jitter points within 1 character width
       set jitter overlap 1.5        # jitter points within 1.5 character width
       set jitter over 1.5 spread 0.5  # same but half the displacement on x

When one or both coordinates of a data set are restricted to discrete values
 then many points may lie exactly on top of each other.  Jittering introduces an
 offset to the coordinates of these superimposed points that spreads them into a
 cluster.  The threshold value for treating the points as being overlapped may
 be specified in character widths or any of the usual coordinate options.
 See `coordinates`.  Jitter affects 2D plot styles `with points` and
 `with impulses`.  It also affects 3D plotting of voxel grids.

The default jittering operation displaces points only along x.
 This produces a distinctive pattern sometimes called a "bee swarm plot".
 The optional keyword `square` adjusts the y coordinate of displaced points
 in addition to their x coordinate so that the points lie in distinct layers
 separated by at least the `overlap` distance.

To jitter along y (only) rather than along x, use keyword `vertical`.

The maximum displacement (in character units) can be limited using the `wrap`
 keyword.

Note that both the overlap criterion and the magnitude of jitter default to
 one character unit.  Thus the plot appearance will change with the terminal
 font size, canvas size, or zoom factor.  To avoid this you can specify the
 overlap criterion in the y axis coordinate system (the `first` keyword) and
 adjust the point size and spread multiplier as appropriate.
 See `coordinates`, `pointsize`.

Caveat: jitter is incompatible with "pointsize variable".

`set jitter` is also useful in 3D plots of voxel data.  Because voxel grids
 are regular lattices of evenly spaced points, many view angles cause points
 to overlap and/or generate Moiré patterns.  These artifacts can be removed
 by displacing the symbol drawn at each grid point by a random amount.
?commands set key
?commands unset key
?commands show key
?set key
?unset key
?show key
?key
?nokey
?legend
 The `set key` command enables a key (or legend) containing a title and a
 sample (line, point, box) for each plot in the graph. The key may be turned off
 by requesting `set key off` or `unset key`.  Individual key entries may be
 turned off by using the `notitle` keyword in the corresponding plot command.
 The text of the titles is controlled by the `set key autotitle` option or by
 the `title` keyword of individual `plot` and `splot` commands.
 See `plot title` for more information.

Syntax:
       set key {on|off} {default}
             {{inside | outside | fixed} | {lmargin | rmargin | tmargin | bmargin}
               | {at <position>}}
             {left | right | center} {top | bottom | center}
             {vertical | horizontal} {Left | Right}
             {{no}enhanced}
             {{no}opaque {fc <colorspec>}}
             {{no}reverse} {{no}invert}
             {samplen <sample_length>} {spacing <line_spacing>}
             {width <width_increment>} {height <height_increment>}
             {{no}autotitle {columnheader}}
             {title {"<text>"} {{no}enhanced} {center | left | right}}
             {font "<face>,<size>"} {textcolor <colorspec>}
             {{no}box {linestyle <style> | linetype <type> | linewidth <width>}}
             {maxcols {<max no. of columns> | auto}}
             {maxrows {<max no. of rows> | auto}}
       unset key
       show key

Elements within the key are stacked according to `vertical` or `horizontal`.
 In the case of `vertical`, the key occupies as few columns as possible.  That
 is, elements are aligned in a column until running out of vertical space at
 which point a new column is started.  The vertical space may be limited using
 'maxrows'.  In the case of `horizontal`, the key occupies as few rows as
 possible.  The horizontal space may be limited using 'maxcols'.

By default the key is placed in the upper right inside corner of the graph.
 The keywords `left`, `right`, `top`, `bottom`, `center`, `inside`, `outside`,
 `lmargin`, `rmargin`, `tmargin`, `bmargin` (, `above`, `over`, `below` and
 `under`) may be used to automatically place the key in other positions of the
 graph.  Also an `at <position>` may be given to indicate precisely where the
 plot should be placed.  In this case, the keywords `left`, `right`, `top`,
 `bottom` and `center` serve an analogous purpose for alignment.
 For more information, see `key placement`.

Justification of the plot titles within the key is controlled by `Left` or
 `Right` (default).  The text and sample can be reversed (`reverse`) and a
 box can be drawn around the key (`box {...}`) in a specified `linetype`
 and `linewidth`, or a user-defined `linestyle`.

The text in the key is set in `enhanced` mode by default, this can be changed
 with the `{no}enhanced` option, also independently for the key title only and
 for each individual plot.

By default the key is built up one plot at a time. That is, the key symbol and
 title are drawn at the same time as the corresponding plot.  That means newer
 plots may sometimes place elements on top of the key.  `set key opaque` causes
 the key to be generated after all the plots.  In this case the key area is
 filled with background color or the requested fill color and then the key
 symbols and titles are written.
 The default can be restored by `set key noopaque`.

By default the first plot label is at the top of the key and successive labels
 are entered below it. The `invert` option causes the first label to be placed
 at the bottom of the key, with successive labels entered above it. This option
 is useful to force the vertical ordering of labels in the key to match the
 order of box types in a stacked histogram.

The <height_increment> is a number of character heights to be added to or
 subtracted from the height of the key box.  This is useful mainly when you are
 putting a box around the key and want larger borders around the key entries.

An overall title can be put on the key (`title "<text>"`)---see also `syntax`
 for the distinction between text in single- or double-quotes. The justification
 of the title defaults to center and can be changed by the keywords `right` or
 `left`

The defaults for `set key` are `on`, `right`, `top`, `vertical`, `Right`,
 `noreverse`, `noinvert`, `samplen 4`, `spacing 1`, `notitle`, and
 `nobox`.  The default <linetype> is the same as that used for the plot
 borders.  Entering `set key default` returns the key to its default
 configuration.

Each plot is represented in the key by a single line containing a line or
 symbol or shape representing the plot style and a corresponding title.
 Using the keyword `notitle` in the plot command will suppress generation of
 the line.  Contour plots generated additional entries in the key, one for
 each contour (see `cntrlabel`). You can add extra lines to the key by inserting
 a dummy plot command that uses the keyword `keyentry` rather than a filename
 or a function.  See `keyentry`.

When using the TeX/LaTeX group of terminals or terminals in which formatting
 information is embedded in the string, `gnuplot` can only estimate the width
 of the string for key positioning.  If the key is to be positioned at the
 left, it may be convenient to use the combination `set key left Left reverse`.

?set key 3D
?set key splot
?key 3D
?key splot
?set key fixed
?key fixed
 Placement of the key for 3D plots (`splot`) by default uses the `fixed` option.
 Note: this is a change from gnuplot version 5.0 and earlier. `fixed` placement
 is very similar to `inside` placement with one important difference.  The plot
 boundaries of a 3D plot change as the view point is rotated or scaled.  If the
 key is positioned `inside` these boundaries then the key also moves when the
 view is changed. `fixed` positioning ignores changes to the view angles or
 scaling; i.e. the key remains fixed in one location on the canvas as the plot
 is rotated.

For 2D plots the `fixed` option is exactly equivalent to `inside`.

If `splot` is being used to draw contours, by default a separate key entry is
 generated for each contour level with a distinct line type.
 To modify this see `set cntrlabel`.
?set key examples
?key examples
 This places the key at the default location:
       set key default

This disables the key:
       unset key

This places a key at coordinates 2,3.5,2 in the default (first) coordinate
 system:
       set key at 2,3.5,2

This places the key below the graph:
       set key below

This places the key in the bottom left corner, left-justifies the text,
 gives it a title, and draws a box around it in linetype 3:
       set key left bottom Left title 'Legend' box 3

?key entries
?keyentry
 Normally each plot autogenerates a single line entry in the key.  If you need
 more control over what appears in the key you can use the `keyentry` keyword
 in the `plot` or `splot` command to insert extra lines.  Instead of providing
 a filename or function to plot, use `keyentry` as a placeholder followed by
 plot style information (used to generate a key symbol) and a title.
 All the usual options for title font, text color, `at` coordinates, and
 enhanced text markup apply.
 Example:
      plot $HEATMAP matrix with image notitle, \
           keyentry with boxes fc palette cb 0 title "no effect", \
           keyentry with boxes fc palette cb 1 title "threshold", \
           keyentry with boxes fc palette cb 3 title "typical range", \
           keyentry with labels nopoint title "as reported in [12]", \
           keyentry with boxes fc palette cb 5 title "strong effect"
?commands set key autotitle
?set key autotitle
?key autotitle
?autotitle
?autotitle columnheader
?key autotitle columnheader
 `set key autotitle` causes each plot to be identified in the key by the name
 of the data file or function used in the plot command. This is the default.
 `set key noautotitle` disables the automatic generation of plot titles.
 The command `set key autotitle columnheader` causes the first entry in each
 column of input data to be interpreted as a text string and used as a title for
 the corresponding plot. If the quantity being plotted is a function of data
 from several columns, gnuplot may be confused as to which column to draw the
 title from. In this case it is necessary to specify the column explicitly in
 the plot command, e.g.

plot "datafile" using (($2+$3)/$4) title columnhead(3) with lines

Note: The effect of `set key autotitle columnheader`, treatment of the first
 line in a data file as column headers rather than data applies even if the
 key is disabled by `unset key`.  It also applies to `stats` and `fit` commands
 even though they generate no key.  If you want the first line of data to be
 treated as column headers but _not_ to use them for plot titles, use
 `set datafile columnheaders`.

In all cases an explicit `title` or `notitle` keyword in the plot command
 itself will override the default from `set key autotitle`.
?commands set key placement
?set key placement
?key placement
 This section describes placement of the primary, auto-generated key.
 To construct a secondary key or place plot titles elsewhere, see
 `multiple keys`.

To understand positioning, the best concept is to think of a region, i.e.,
 inside/outside, or one of the margins.  Along with the region, keywords
 `left/center/right` (l/c/r) and `top/center/bottom` (t/c/b) control where
 within the particular region the key should be placed.

When in `inside` mode, the keywords `left` (l), `right` (r), `top` (t),
 `bottom` (b), and `center` (c) push the key out toward the plot boundary as
 illustrated:

t/l   t/c   t/r

c/l    c    c/r

b/l   b/c   b/r

When in `outside` mode, automatic placement is similar to the above
 illustration, but with respect to the view, rather than the graph boundary.
 That is, a border is moved inward to make room for the key outside of
 the plotting area, although this may interfere with other labels and may
 cause an error on some devices.  The particular plot border that is moved
 depends upon the position described above and the stacking direction.  For
 options centered in one of the dimensions, there is no ambiguity about which
 border to move.  For the corners, when the stack direction is `vertical`, the
 left or right border is moved inward appropriately.  When the stack direction
 is `horizontal`, the top or bottom border is moved inward appropriately.

The margin syntax allows automatic placement of key regardless of stack
 direction.  When one of the margins `lmargin` (lm), `rmargin` (rm),
 `tmargin` (tm), and `bmargin` (bm) is combined with a single, non-conflicting
 direction keyword, the following illustrated positions may contain the key:

l/tm  c/tm  r/tm

t/lm                  t/rm

c/lm                  c/rm

b/lm                  b/rm

l/bm  c/bm  r/bm

Keywords `above` and `over` are synonymous with `tmargin`.  For version
 compatibility, `above` or `over` without an additional l/c/r or stack direction
 keyword uses `center` and `horizontal`.  Keywords `below` and `under` are
 synonymous with `bmargin`.  For compatibility, `below` or `under` without an
 additional l/c/r or stack  direction keyword uses `center` and `horizontal`.  A
 further compatibility issue is that `outside` appearing without an additional
 t/b/c or stack direction keyword uses `top`, `right` and `vertical` (i.e., the
 same as t/rm above).

The <position> can be a simple x,y,z as in previous versions, but these can
 be preceded by one of five keywords (`first`, `second`, `graph`, `screen`,
 `character`) which selects the coordinate system in which the position of
 the first sample line is specified.  See `coordinates` for more details.
 The effect of `left`, `right`, `top`, `bottom`, and `center` when <position>
 is given is to align the key as though it were text positioned using the
 label command, i.e., `left` means left align with key to the right of
 <position>, etc.
?commands set key samples
?set key samples
?key samples
 By default, each plot on the graph generates a corresponding entry in the key.
 This entry contains a plot title and a sample line/point/box of the same color
 and fill properties as used in the plot itself.  The font and textcolor
 properties control the appearance of the individual plot titles that appear in
 the key. Setting the textcolor to "variable" causes the text for each key
 entry to be the same color as the line or fill color for that plot.
 This was the default in some earlier versions of gnuplot.

The length of the sample line can be controlled by `samplen`.  The sample
 length is computed as the sum of the tic length and <sample_length> times the
 character width.  `samplen` also affects the positions of point samples in
 the key since these are drawn at the midpoint of the sample line, even if
 the sample line itself is not drawn.

Key entry lines are single-spaced based on the current font size.
 This can be adjusted by `set key spacing <line-spacing>`.

The <width_increment> is a number of character widths to be added to or
 subtracted from the length of the string.  This is useful only when you are
 putting a box around the key and you are using control characters in the text.
 `gnuplot` simply counts the number of characters in the string when computing
 the box width; this allows you to correct it.
?multiple keys
?set key multiple keys
?key multiple keys
 It is possible to construct a legend/key manually rather than having the plot
 titles all appear in the auto-generated key. This allows, for example, creating
 a single legend for the component panels in a multiplot.
 Here is an example:
        set multiplot layout 3,2 columnsfirst
        set style data boxes
        plot $D using 0:6  lt 1 title at 0.75, 0.20
        plot $D using 0:12 lt 2 title at 0.75, 0.17
        plot $D using 0:13 lt 3 title at 0.75, 0.14
        plot $D using 0:14 lt 4 title at 0.75, 0.11
        set label 1 at screen 0.75, screen 0.22 "Custom combined key area"
        plot $D using 0:($6+$12+$13+$14) with linespoints title "total"
        unset multiplot
?commands set label
?commands unset label
?commands show label
?set label
?unset label
?show label
?label
?nolabel
 Arbitrary labels can be placed on the plot using the `set label` command.

Syntax:
       set label {<tag>} {"<label text>"} {at <position>}
                 {left | center | right}
                 {norotate | rotate {by <degrees>}}
                 {font "<name>{,<size>}"}
                 {noenhanced}
                 {front | back}
                 {textcolor <colorspec>}
                 {point <pointstyle> | nopoint}
                 {offset <offset>}
                 {nobox} {boxed {bs <boxstyle>}}
                 {hypertext}
       unset label {<tag>}
       show label

The <position> is specified by either x,y or x,y,z, and may be preceded by
 `first`, `second`, `polar`, `graph`, `screen`, or `character` to indicate the
 coordinate system.  See `coordinates` for details.

The tag is an integer that is used to identify the label. If no <tag>
 is given, the lowest unused tag value is assigned automatically.  The
 tag can be used to delete or modify a specific label.  To change any
 attribute of an existing label, use the `set label` command with the
 appropriate tag, and specify the parts of the label to be changed.

The <label text> can be a string constant, a string variable, or a string-
 valued expression. See `strings`, `sprintf`, and `gprintf`.

By default, the text is placed flush left against the point x,y,z.  To adjust
 the way the label is positioned with respect to the point x,y,z, add the
 justification parameter, which may be `left`, `right` or `center`,
 indicating that the point is to be at the left, right or center of the text.
 Labels outside the plotted boundaries are permitted but may interfere with
 axis labels or other text.

Some terminals support enclosing the label in a box.  See `set style textbox`.
 Not all terminals can handle boxes for rotated text.

If `rotate` is given, the label is written vertically. If `rotate by <degrees>`
 is given, the baseline of the text will be set to the specified angle.
 Some terminals do not support text rotation.

Font and its size can be chosen explicitly by `font "<name>{,<size>}"` if the
 terminal supports font settings.  Otherwise the default font of the terminal
 will be used.

Normally the enhanced text mode string interpretation, if enabled for the
 current terminal, is applied to all text strings including label text.
 The `noenhanced` property can be used to exempt a specific label from the
 enhanced text mode processing.  The can be useful if the label contains
 underscores, for example. See `enhanced text`.

If `front` is given, the label is written on top of the graphed data. If
 `back` is given (the default), the label is written underneath the graphed
 data.  Using `front` will prevent a label from being obscured by dense data.

`textcolor <colorspec>` changes the color of the label text. <colorspec> can be
 a linetype, an rgb color, or a palette mapping. See help for `colorspec` and
 `palette`.  `textcolor` may be abbreviated `tc`.
    `tc default` resets the text color to its default state.
    `tc lt <n>` sets the text color to that of line type <n>.
    `tc ls <n>` sets the text color to that of line style <n>.
    `tc palette z` selects a palette color corresponding to the label z position.
    `tc palette cb <val>` selects a color corresponding to <val> on the colorbar.
    `tc palette fraction <val>`, with 0<=val<=1, selects a color corresponding to
        the mapping [0:1] to grays/colors of the `palette`.
    `tc rgb "#RRGGBB"` or `tc rgb "0xRRGGBB"` sets an arbitrary 24-bit RGB color.
    `tc rgb 0xRRGGBB`  As above; a hexadecimal constant does not require quotes.

If a <pointstyle> is given, using keywords `lt`, `pt` and `ps`, see `style`,
 a point with the given style and color of the given line type is plotted at
 the label position and the text of the label is displaced slightly.
 This option is used by default for placing labels in `mouse` enhanced
 terminals.  Use `nopoint` to turn off the drawing of a point near
 the label (this is the default).

The displacement defaults to 1,1 in `pointsize` units if a <pointstyle> is
 given, 0,0 if no <pointstyle> is given.  The displacement can be controlled
 by the optional `offset <offset>` where <offset> is specified by either x,y
 or x,y,z, and may be preceded by `first`, `second`, `graph`, `screen`, or
 `character` to select the coordinate system.  See `coordinates` for details.

If one (or more) axis is timeseries, the appropriate coordinate should be
 given as a quoted time string according to the `timefmt` format string.
 See `set xdata` and `set timefmt`.

The options available for `set label` are also available for the `labels` plot
 style. See `labels`.  In this case the properties `textcolor`, `rotate`, and
 `pointsize` may be followed by keyword `variable` rather than by a fixed value.
 In this case the corresponding property of individual labels is determined by
 additional columns in the `using` specifier.

?label examples
?set label examples
 Examples:

To set a label at (1,2) to "y=x", use:
       set label "y=x" at 1,2

To set a Sigma of size 24, from the Symbol font set, at the center of
 the graph, use:
       set label "S" at graph 0.5,0.5 center font "Symbol,24"

To set a label "y=x^2" with the right of the text at (2,3,4), and tag the
 label as number 3, use:
       set label 3 "y=x^2" at 2,3,4 right

To change the preceding label to center justification, use:
       set label 3 center

To delete label number 2, use:
       unset label 2

To delete all labels, use:
       unset label

To show all labels (in tag order), use:
       show label

To set a label on a graph with a timeseries on the x axis, use, for example:
       set timefmt "%d/%m/%y,%H:%M"
       set label "Harvest" at "25/8/93",1

To display a freshly fitted parameter on the plot with the data and the
 fitted function, do this after the `fit`, but before the `plot`:
       set label sprintf("a = %3.5g",par_a) at 30,15
       bfit = gprintf("b = %s*10^%S",par_b)
       set label bfit at 30,20

To display a function definition along with its fitted parameters, use:
       f(x)=a+b*x
       fit f(x) 'datafile' via a,b
       set label GPFUN_f at graph .05,.95
       set label sprintf("a = %g", a) at graph .05,.90
       set label sprintf("b = %g", b) at graph .05,.85

To set a label displaced a little bit from a small point:
       set label 'origin' at 0,0 point lt 1 pt 2 ps 3 offset 1,-1

To set a label whose color matches the z value (in this case 5.5) of some
 point on a 3D splot colored using pm3d:
       set label 'text' at 0,0,5.5 tc palette z
?hypertext
?label hypertext
?set label hypertext
 Some terminals (wxt, qt, svg, canvas, win) allow you to attach hypertext
 to specific points on the graph or elsewhere on the canvas. When the mouse
 hovers over the anchor point, a pop-up box containing the text is displayed.
 Terminals that do not support hypertext will display nothing. You must enable
 the `point` attribute of the label in order for the hypertext to be anchored.
 Examples:
       set label at 0,0 "Plot origin" hypertext point pt 1
       plot 'data' using 1:2:0 with labels hypertext point pt 7 \
            title 'mouse over point to see its order in data set'

For the wxt and qt terminals, left-click on a hypertext anchor after the
 text has appeared will copy the hypertext to the clipboard.

EXPERIMENTAL (implementation details may change)
 Text of the form "image{<xsize>,<ysize>}:<filename>{\n<caption text>}" will
 trigger display of the image file in a pop-up box. The optional size overrides
 a default box size 300x200.  The types of image file recognized may vary by
 terminal type, but *.png should always work. Any additional text lines
 following the image filename are displayed as usual for hypertext.
 Example:
       set label 7 "image:../figures/Fig7_inset.png\nFigure 7 caption..."
       set label 7 at 10,100 hypertext point pt 7
?commands set linetype
?commands show linetype
?set linetype
?show linetype
?linetype
 The `set linetype` command allows you to redefine the basic linetypes used
 for plots.  The command options are identical to those for "set style line".
 Unlike line styles, redefinitions by `set linetype` are persistent;  they
 are not affected by `reset`.

For example, whatever linetypes one and two look like to begin with, if you
 redefine them like this:

set linetype 1 lw 2 lc rgb "blue" pointtype 6
       set linetype 2 lw 2 lc rgb "forest-green" pointtype 8

everywhere that uses lt 1 will now get a thick blue line.  This includes
 uses such as the definition of a temporary linestyle derived from the base
 linetype 1.  Similarly lt 2 will now produce a thick green line.

This mechanism can be used to define a set of personal preferences for the
 sequence of lines used in gnuplot.  The recommended way to do this is to add
 to the run-time initialization file ~/.gnuplot a sequence of commands like

set linetype 1 lc rgb "dark-violet" lw 2 pt 1
       set linetype 2 lc rgb "sea-green"   lw 2 pt 7
       set linetype 3 lc rgb "cyan"        lw 2 pt 6 pi -1
       set linetype 4 lc rgb "dark-red"    lw 2 pt 5 pi -1
       set linetype 5 lc rgb "blue"        lw 2 pt 8
       set linetype 6 lc rgb "dark-orange" lw 2 pt 3
       set linetype 7 lc rgb "black"       lw 2 pt 11
       set linetype 8 lc rgb "goldenrod"   lw 2
       set linetype cycle 8

Every time you run gnuplot the line types will be initialized to these values.
 You may initialize as many linetypes as you like. If you do not redefine, say,
 linetype 3 then it will continue to have the default properties (in this case
 blue, pt 3, lw 1, etc).

Similar script files can be used to define theme-based color choices, or sets
 of colors optimized for a particular plot type or output device.

The command `set linetype cycle 8` tells gnuplot to re-use these definitions
 for the color and linewidth of higher-numbered linetypes.  That is, linetypes
 9-16, 17-24, and so on will use this same sequence of colors and widths.
 The point properties (pointtype, pointsize, pointinterval) are not affected by
 this command.  `unset linetype cycle` disables this feature.  If the line
 properties of a higher numbered linetype are explicitly defined, this takes
 precedence over the recycled low-number linetype properties.
?commands set link
?set link
?link
 Syntax:
       set link {x2 | y2} {via <expression1> inverse <expression2>}
       unset link

The `set link` command establishes a mapping between the x and x2 axes, or the
 y and y2 axes.  <expression1> maps primary axis coordinates onto the secondary
 axis.  <expression2> maps secondary axis coordinates onto the primary axis.

Examples:

set link x2

This is the simplest form of the command. It forces the x2 axis to have
 identically the same range, scale, and direction as the x axis.
 Commands `set xrange`, `set x2range`, `set auto x`, etc will affect both the
 x and x2 axes.

set link x2 via x**2 inverse sqrt(x)
       plot "sqrt_data" using 1:2 axes x2y1, "linear_data" using 1:2 axes x1y1

This command establishes forward and reverse mapping between the x and x2 axes.
 The forward mapping is used to generate x2 tic labels and x2 mouse coordinate
 The reverse mapping is used to plot coordinates given in the x2 coordinate
 system.  Note that the mapping as given is valid only for x non-negative. When
 mapping to the y2 axis, both <expression1> and <expression2> must use y as
 dummy variable.
?commands set lmargin
?set lmargin
?lmargin
 The command `set lmargin` sets the size of the left margin.
 Please see `set margin` for details.
?commands set loadpath
?commands show loadpath
?set loadpath
?show loadpath
?loadpath
 The `loadpath` setting defines additional locations for data and command
 files searched by the `call`, `load`, `plot` and `splot` commands.  If a
 file cannot be found in the current directory, the directories in
 `loadpath` are tried.

Syntax:
       set loadpath {"pathlist1" {"pathlist2"...}}
       show loadpath

Path names may be entered as single directory names, or as a list of
 path names separated by a platform-specific path separator, eg. colon
 (':') on Unix, semicolon (';') on DOS/Windows/OS/2 platforms.
 The `show loadpath`, `save` and `save set` commands replace the
 platform-specific separator with a space character (' ').

If the environment variable GNUPLOT_LIB is set, its contents are appended to
 `loadpath`.  However, `show loadpath` prints the contents of `set loadpath`
 and GNUPLOT_LIB separately.  Also, the `save` and `save set` commands ignore
 the contents of GNUPLOT_LIB.
?commands set locale
?set locale
?locale
 The `locale` setting determines the language with which `{x,y,z}{d,m}tics`
 will write the days and months.

Syntax:
       set locale {"<locale>"}

<locale> may be any language designation acceptable to your installation.
 See your system documentation for the available options.  The command
 `set locale ""` will try to determine the locale from the LC_TIME, LC_ALL,
 or LANG environment variables.

To change the decimal point locale, see `set decimalsign`.
 To change the character encoding to the current locale, see `set encoding`.
?commands set logscale
?commands unset logscale
?commands show logscale
?set logscale
?unset logscale
?show logscale
?set log
?logscale
?nologscale
 Syntax:
       set logscale <axes> {<base>}
       unset logscale <axes>
       show logscale

where <axes> may be any combinations of `x`, `x2`, `y`, `y2`, `z`, `cb`, and
 `r` in any order.  <base> is the base of the log scaling (default is base 10).
 If no axes are specified, the command affects all axes except `r`.
 The command `unset logscale` turns off log scaling for all axes.
 Note that the ticmarks generated for logscaled axes are not uniformly spaced.
 See `set xtics`.

Examples:

To enable log scaling in both x and z axes:
       set logscale xz

To enable scaling log base 2 of the y axis:
       set logscale y 2

To enable z and color log axes for a pm3d plot:
       set logscale zcb

To disable z axis log scaling:
       unset logscale z
?commands set macros
?set macros
 In this version of gnuplot macro substitution is always enabled.
 Tokens in the command line of the form @<stringvariablename> will be replaced
 by the text string contained in <stringvariablename>. See `substitution`.
?commands set mapping
?commands show mapping
?set mapping
?show mapping
?mapping
 If data are provided to `splot` in spherical or cylindrical coordinates,
 the `set mapping` command should be used to instruct `gnuplot` how to
 interpret them.

Syntax:
       set mapping {cartesian | spherical | cylindrical}

A cartesian coordinate system is used by default.

For a spherical coordinate system, the data occupy two or three columns
 (or `using` entries).  The first two are interpreted as the azimuthal
 and polar angles theta and phi (or "longitude" and "latitude"), in the
 units specified by `set angles`.  The radius r is taken from the third
 column if there is one, or is set to unity if there is no third column.
 The mapping is:

x = r * cos(theta) * cos(phi)
       y = r * sin(theta) * cos(phi)
       z = r * sin(phi)

Note that this is a "geographic" spherical system, rather than a "polar"
 one (that is, phi is measured from the equator, rather than the pole).

For a cylindrical coordinate system, the data again occupy two or three
 columns.  The first two are interpreted as theta (in the units specified by
 `set angles`) and z.  The radius is either taken from the third column or set
 to unity, as in the spherical case.  The mapping is:

x = r * cos(theta)
       y = r * sin(theta)
       z = z

The effects of `mapping` can be duplicated with the `using` filter on the
 `splot` command, but `mapping` may be more convenient if many data files are
 to be processed.  However even if `mapping` is used, `using` may still be
 necessary if the data in the file are not in the required order.

`mapping` has no effect on `plot`.
 world.dem: mapping demos.
?commands set margins
?commands show margins
?set margin
?set margins
?show margins
?margins
 The `margin` is the distance between the plot border and the outer edge of the
 canvas. The size of the margin is chosen automatically, but can be overridden
 by the `set margin` commands.  `show margin` shows the current settings.
 To alter the distance between the inside of the plot border and the data in the
 plot itself, see `set offsets`.

Syntax:
       set lmargin {{at screen} <margin>}
       set rmargin {{at screen} <margin>}
       set tmargin {{at screen} <margin>}
       set bmargin {{at screen} <margin>}
       set margins <left>, <right>, <bottom>, <top>
       show margin

The default units of <margin> are character heights or widths, as appropriate.
 A positive value defines the absolute size of the margin.  A negative value
 (or none) causes `gnuplot` to revert to the computed value.  For 3D plots,
 only the left margin can be set using character units.

The keywords `at screen` indicates that the margin is specified as a fraction
 of the full drawing area. This can be used to precisely line up the corners of
 individual 2D and 3D graphs in a multiplot. This placement ignores the current
 values of `set origin` and `set size`, and is intended as an alternative
 method for positioning graphs within a multiplot.

Normally the margins of a plot are automatically calculated based on tics,
 tic labels, axis labels, the plot title, the timestamp and the size of the
 key if it is outside the borders.  If, however, tics are attached to the
 axes (`set xtics axis`, for example), neither the tics themselves nor their
 labels will be included in either the margin calculation or the calculation
 of the positions of other text to be written in the margin.  This can lead
 to tic labels overwriting other text if the axis is very close to the border.
?commands set micro
?commands show micro
?commands unset micro
?set micro
?show micro
?unset micro
?micro
 By default the "%c" format specifier for scientific notation used to generate
 axis tick labels uses a lower case u as a prefix to indicate "micro" (10^-6).
 The `set micro` command tells gnuplot to use a different typographic
 character (unicode U+00B5).  The byte sequence used to represent this character
 depends on the current encoding.  See `format specifiers`, `encoding`.

This command is EXPERIMENTAL. Implementation details may change.

?commands set minussign
?commands show minussign
?commands unset minussign
?set minussign
?show minussign
?unset minussign
?minussign
 Gnuplot uses the C language library routine sprintf() for most formatted input.
 However it also has its own formatting routine `gprintf()` that is used to
 generate axis tic labels. The C library routine always use a hyphen character
 (ascii \055) to indicate a negative number, as in -7.  Many people prefer a
 different typographic minus sign character (unicode U+2212) for this purpose,
 as in −7.  The command

set minussign

causes gprintf() to use this minus sign character rather than a hyphen in
 numeric output. In a utf-8 locale this is the multibyte sequence corresponding
 to unicode U+2212.  In a Window codepage 1252 locale this is the 8-bit
 character ALT+150 ("en dash").  The `set minussign` command will affect axis
 tic labels and any labels that are created by explicitly invoking gprintf.
 It has no effect on other strings that contain a hyphen.  See `gprintf`.

Note that this command is ignored when you are using any of the LaTeX
 terminals, as LaTeX has its own mechanism for handling minus signs.
 It also is not necessary when using the postscript terminal because the
 postscript prologue output by gnuplot remaps the ascii hyphen code \055 to a
 different glyph named `minus`.

This command is EXPERIMENTAL. Implementation details may change.

Example (assumes utf8 locale):

set minus
      A = -5
      print "A = ",A                 # printed string will contain a hyphen
      print gprintf("A = %g",A)      # printed string will contain character U+2212
      set label "V = -5"             # label will contain a hyphen
      set label sprintf("V = %g",-5) # label will contain a hyphen
      set label gprintf("V = %g",-5) # label will contain character U+2212
?commands set monochrome
?set monochrome
?monochrome
 Syntax:
      set monochrome {linetype N <linetype properties>}

The `set monochrome` command selects an alternative set of linetypes that
 differ by dot/dash pattern or line width rather than by color.  This command
 replaces the monochrome option offered by certain terminal types in earlier
 versions of gnuplot.  For backward compatibility these terminal types now
 implicitly invoke "set monochrome" if their own "mono" option is present.
 For example,
      set terminal pdf mono
 is equivalent to
      set terminal pdf
      set mono

Selecting monochrome mode does not prevent you from explicitly drawing lines
 using RGB or palette colors, but see also `set palette gray`.
 Six monochrome linetypes are defined by default.  You can change their
 properties or add additional monochrome linetypes by using the full form of the
 command.  Changes made to the monochrome linetypes do not affect the color
 linetypes and vice versa.  To restore the usual set of color linetypes, use
 either `unset monochrome` or `set color`.
?commands set mouse
?commands unset mouse
?set mouse
?unset mouse
?mousing
?mouse
?nomouse
 The command `set mouse` enables mouse actions for the current interactive
 terminal.  It is usually enabled by default in interactive mode, but disabled
 by default if commands are being read from a file.

There are two mouse modes. The 2D mode works for `plot` commands and for `splot`
 maps (i.e. `set view` with z-rotation 0, 90, 180, 270 or 360 degrees, including
 `set view map`).  In this mode the mouse position is tracked and you can pan or
 zoom using the mouse buttons or arrow keys.  Some terminals support toggling
 individual plots on/off by clicking on the corresponding key title or on a
 separate widget.

For 3D graphs `splot`, the view and scaling of the graph can be changed with
 mouse buttons 1 and 2, respectively. A vertical motion of Button 2 with the
 shift key held down changes the `xyplane`.  If additionally to these
 buttons the modifier <ctrl> is held down, the coordinate axes are displayed
 but the data are suppressed.  This is useful for large data sets.
 Mouse button 3 controls the azimuth of the z axis (see `set view azimuth`).

Mousing is not available inside multiplot mode. When multiplot is completed
 using `unset multiplot`, then the mouse will be turned on again but acts only
 on the most recent plot within the multiplot (like replot does).

Syntax:
       set mouse {doubleclick <ms>} {nodoubleclick}
                 {{no}zoomcoordinates}
                 {zoomfactors <xmultiplier>, <ymultiplier>}
                 {noruler | ruler {at x,y}}
                 {polardistance{deg|tan} | nopolardistance}
                 {format <string>}
                 {mouseformat <int> | <string> | function <f(x,y)>}
                 {{no}labels {"labeloptions"}}
                 {{no}zoomjump} {{no}verbose}
       unset mouse

The options `noruler` and `ruler` switch the ruler off and on, the latter
 optionally setting the origin at the given coordinates. While the ruler is on,
 the distance in user units from the ruler origin to the mouse is displayed
 continuously. By default, toggling the ruler has the key binding 'r'.

The option `polardistance` determines if the distance between the mouse cursor
 and the ruler is also shown in polar coordinates (distance and angle in
 degrees or tangent (slope)). This corresponds to the default key binding '5'.

Choose the option `labels` to define persistent gnuplot labels using Button 2.
 The default is `nolabels`, which makes Button 2 draw only a temporary label at
 the mouse position. Labels are drawn with the current setting of `mouseformat`.
 The `labeloptions` string is passed to the `set label` command.  The default is
 "point pointstyle 1" which will plot a small plus at the label position.
 Temporary labels will disappear at the next `replot` or mouse zoom operation.
 Persistent labels can be removed by holding the Ctrl-Key down while clicking
 Button 2 on the label's point. The threshold for how close you must be to the
 label is also determined by the `pointsize`.

If the option `verbose` is turned on the communication commands are shown
 during execution. This option can also be toggled by hitting `6` in the
 driver's window. `verbose` is off by default.

Press 'h' in the driver's window for a short summary of the mouse and key
 bindings.  This will also display user defined bindings or `hotkeys` which
 can be defined using the `bind` command, see help for `bind`.  Note, that user
 defined `hotkeys` may override the default bindings.
 See also help for `bind` and `label`.
?set mouse doubleclick
?mouse doubleclick
 The doubleclick resolution is given in milliseconds and used for Button 1,
 which copies the current mouse position to the `clipboard` on some terminals.
 The default value is 300 ms.  Setting the value to 0 ms triggers the copy on
 a single click.
?set mouse format
?mouse format
 The `set mouse format` command specifies a format string for sprintf() which
 determines how the mouse cursor [x,y] coordinates are printed to the plot
 window and to the clipboard.  The default is "% #g".

This setting is superseded by "set mouse mouseformat".
?set mouse mouseformat
?mouseformat
 Syntax:
      set mouse mouseformat i
      set mouse mouseformat "custom format"
      set mouse mouseformat function string_valued_function(x, y)
 This command controls the format used to report the current mouse position.
 An integer argument selects one of the format options in the table below.
 A string argument is used as a format for sprintf() in option 7 and should
 contain two float specifiers, one for x and one for y.

Use of a custom function returning a string is EXPERIMENTAL.
 It allows readout of coordinate systems in which inverse mapping from screen
 coordinates to plot coordinates requires joint consideration of both x and y.
 See for example the map_projection demo.

Example:
      `set mouse mouseformat "mouse x,y = %5.2g, %10.3f"`.
 Use `set mouse mouseformat ""` to turn this string off again.

The following formats are available:

0   default (same as 1)
  1   axis coordinates                    1.23, 2.45
  2   graph coordinates (from 0 to 1)    /0.00, 1.00/
  3   x = timefmt     y = axis           [(as set by `set timefmt`), 2.45]
  4   x = date        y = axis           [31. 12. 1999, 2.45]
  5   x = time        y = axis           [23:59, 2.45]
  6   x = date time   y = axis           [31. 12. 1999 23:59, 2.45]
  7   format from `set mouse mouseformat <format-string>`
  8   format from `set mouse mouseformat function <func>`
?set mouse scrolling
?mouse scrolling
?mouse wheel
?scrolling
?mousewheel
 X and Y axis scaling in both 2D and 3D graphs can be adjusted using the
 mouse wheel.  <wheel-up> scrolls up (increases both YMIN and YMAX by ten
 percent of the Y range, and increases both Y2MIN and Y2MAX likewise), and
 <wheel down> scrolls down.  <shift-wheel-up> scrolls left (decreases both
 XMIN and XMAX, and both X2MIN and X2MAX), and <shift-wheel-down> scrolls
 right.  <control-wheel-up> zooms in toward the center of the plot, and
 <control-wheel-down> zooms out.  <shift-control-wheel-up> zooms in along the
 X and X2 axes only, and <shift-control-wheel-down> zooms out along the X and
 X2 axes only.
?mouse x11_mouse
?x11_mouse
?x11 mouse
 If multiple X11 plot windows have been opened using the `set term x11 <n>`
 terminal option, then only the current plot window supports the entire
 range of mouse commands and hotkeys.  The other windows will, however,
 continue to display mouse coordinates at the lower left.
?mouse zoom
?zoom
 Zooming is usually accomplished by holding down the left mouse button and
 dragging the mouse to delineate a zoom region.  Some platforms may require
 using a different mouse button.  The original plot can be restored by typing
 the 'u' hotkey in the plot window.  The hotkeys 'p' and 'n' step back and
 forth through a history of zoom operations.

The option `zoomcoordinates` determines if the coordinates of the zoom box are
 drawn at the edges while zooming. This is on by default.

If the option `zoomjump` is on, the mouse pointer will be automatically
 offset a small distance after starting a zoom region with button 3. This can
 be useful to avoid a tiny (or even empty) zoom region. `zoomjump` is off by
 default.

?commands set mttics
?commands unset mttics
?commands show mttics
?set mttics
?unset mttics
?show mttics
?mttics
?nomttics
 Minor tic marks around the perimeter of a polar plot are controlled by
 by `set mttics`. Please see `set mxtics`.
?commands set multiplot
?commands unset multiplot
?set multiplot
?unset multiplot
?multiplot
?nomultiplot
?layout
 The command `set multiplot` places `gnuplot` in the multiplot mode, in which
 several plots are placed next to each other on the same page or screen window.

Syntax:
       set multiplot
           { title <page title> {font <fontspec>} {enhanced|noenhanced} }
           { layout <rows>,<cols>
             {rowsfirst|columnsfirst} {downwards|upwards}
             {scale <xscale>{,<yscale>}} {offset <xoff>{,<yoff>}}
             {margins <left>,<right>,<bottom>,<top>}
             {spacing <xspacing>{,<yspacing>}}
           }
       set multiplot {next|previous}
       unset multiplot

For some terminals, no plot is displayed until the command `unset multiplot`
 is given, which causes the entire page to be drawn and then returns gnuplot
 to its normal single-plot mode.  For other terminals, each separate `plot`
 command produces an updated display.

The `clear` command is used to erase the rectangular area of the page that will
 be used for the next plot.  This is typically needed to inset a small plot
 inside a larger plot.

Any labels or arrows that have been defined will be drawn for each plot
 according to the current size and origin (unless their coordinates are
 defined in the `screen` system).  Just about everything else that can be
 `set` is applied to each plot, too.  If you want something to appear only
 once on the page, for instance a single time stamp, you'll need to put a `set
 time`/`unset time` pair around one of the `plot`, `splot` or `replot`
 commands within the `set multiplot`/`unset multiplot` block.

The multiplot title is separate from the individual plot titles, if any.
 Space is reserved for it at the top of the page, spanning the full width
 of the canvas.

The commands `set origin` and `set size` must be used to correctly position
 each plot if no layout is specified or if fine tuning is desired.  See
 `set origin` and `set size` for details of their usage.

Example:
       set multiplot
       set size 0.4,0.4
       set origin 0.1,0.1
       plot sin(x)
       set size 0.2,0.2
       set origin 0.5,0.5
       plot cos(x)
       unset multiplot

This displays a plot of cos(x) stacked above a plot of sin(x).

`set size` and `set origin` refer to the entire plotting area used for each
 plot.  Please also see `set term size`.  If you want to have the axes
 themselves line up, you can guarantee that the margins are the same size with
 the `set margin` commands.  See `set margin` for their use.  Note that the
 margin settings are absolute, in character units, so the appearance of the
 graph in the remaining space will depend on the screen size of the display
 device, e.g., perhaps quite different on a video display and a printer.

With the `layout` option you can generate simple multiplots without having
 to give the `set size` and `set origin` commands before each plot:  Those
 are generated automatically, but can be overridden at any time.  With
 `layout` the display will be divided by a grid with <rows> rows and
 <cols> columns.  This grid is filled rows first or columns first depending on
 whether the corresponding option is given in the multiplot command.  The stack
 of plots can grow `downwards` or `upwards`.
 Default is `rowsfirst` and `downwards`.
 The commands `set multiplot next` and `set multiplot previous` are relevant
 only in the context of using the layout option.  `next` skips the next position
 in the grid, leaving a blank space. `prev` returns to the grid position
 immediately preceding the most recently plotted position.

Each plot can be scaled by `scale` and shifted with `offset`; if the y-values
 for scale or offset are omitted, the x-value will be used.  `unset multiplot`
 will turn off the automatic layout and restore the values of `set size` and
 `set origin` as they were before `set multiplot layout`.

Example:
       set size 1,1
       set origin 0,0
       set multiplot layout 3,2 columnsfirst scale 1.1,0.9
       [ up to 6 plot commands here ]
       unset multiplot

The above example will produce 6 plots in 2 columns filled top to bottom,
 left to right.  Each plot will have a horizontal size of 1.1/2 and a vertical
 size of 0.9/3.

Another possibility is to set uniform margins for all plots in the layout with
 options `layout margins` and `spacing`, which must be used together. With
 `margins` you set the outer margins of the whole multiplot grid.

`spacing` gives the gap size between two adjacent subplots, and can also
 be given in `character` or `screen` units. If a single value is given,
 it is used for both x and y direction, otherwise two different values
 can be selected.

If one value has no unit, the one of the preceding margin setting is used.

Example:
       set multiplot layout 2,2 margins 0.1, 0.9, 0.1, 0.9 spacing 0.0

In this case the two left-most subplots will have left boundaries at screen
 coordinate 0.1, the two right-most subplots will have right boundaries at
 screen coordinate 0.9, and so on.  Because the spacing between subplots is
 given as 0, their inner boundaries will superimpose.

Example:
       set multiplot layout 2,2 margins char 5,1,1,2 spacing screen 0, char 2

This produces a layout in which the boundary of both left subplots is
 5 character widths from the left edge of the canvas, the right boundary of the
 right subplots is 1 character width from the canvas edge.
 The overall bottom margin is one character height and the overall top margin
 is 2 character heights. There is no horizontal gap between the two columns of
 subplots. The vertical gap between subplots is equal to 2 character heights.

Example:
       set multiplot layout 2,2 columnsfirst margins 0.1,0.9,0.1,0.9 spacing 0.1
       set ylabel 'ylabel'
       plot sin(x)
       set xlabel 'xlabel'
       plot cos(x)
       unset ylabel
       unset xlabel
       plot sin(2*x)
       set xlabel 'xlabel'
       plot cos(2*x)
       unset multiplot

See also
 multiplot demo (multiplt.dem)
?commands set mx2tics
?commands unset mx2tics
?commands show mx2tics
?set mx2tics
?unset mx2tics
?show mx2tics
?mx2tics
?nomx2tics
 Minor tic marks along the x2 (top) axis are controlled by `set mx2tics`.
 Please see `set mxtics`.
?commands set mxtics
?commands unset mxtics
?commands show mxtics
?set mxtics
?unset mxtics
?show mxtics
?mxtics
?nomxtics
 Minor tic marks along the x axis are controlled by `set mxtics`.  They can be
 turned off with `unset mxtics`.  Similar commands control minor tics along
 the other axes.

Syntax:
       set mxtics {<freq> | default}
       unset mxtics
       show mxtics

The same syntax applies to `mytics`, `mztics`, `mx2tics`, `my2tics`, `mrtics`,
 `mttics` and `mcbtics`.

<freq> is the number of sub-intervals (NOT the number of minor tics) between
 major tics (the default for a linear axis is either two or five
 depending on the major tics, so there are one or four minor
 tics between major tics). Selecting `default` will return the number of minor
 ticks to its default value.

If the axis is logarithmic, the number of sub-intervals will be set to a
 reasonable number by default (based upon the length of a decade).  This will
 be overridden if <freq> is given.  However the usual minor tics (2, 3, ...,
 8, 9 between 1 and 10, for example) are obtained by setting <freq> to 10,
 even though there are but nine sub-intervals.

To set minor tics at arbitrary positions, use the ("<label>" <pos> <level>,
 ...) form of `set {x|x2|y|y2|z}tics` with <label> empty and <level> set to 1.

The `set m{x|x2|y|y2|z}tics` commands work only when there are uniformly
 spaced major tics.  If all major tics were placed explicitly by
 `set {x|x2|y|y2|z}tics`, then minor tic commands are ignored.  Implicit
 major tics and explicit minor tics can be combined using
 `set {x|x2|y|y2|z}tics` and `set {x|x2|y|y2|z}tics add`.

Examples:
       set xtics 0, 5, 10
       set xtics add (7.5)
       set mxtics 5
 Major tics at 0,5,7.5,10, minor tics at 1,2,3,4,6,7,8,9
       set logscale y
       set ytics format ""
       set ytics 1e-6, 10, 1
       set ytics add ("1" 1, ".1" 0.1, ".01" 0.01, "10^-3" 0.001, \
                      "10^-4" 0.0001)
       set mytics 10
 Major tics with special formatting, minor tics at log positions

By default, minor tics are off for linear axes and on for logarithmic axes.
 They inherit the settings for `axis|border` and `{no}mirror` specified for
 the major tics.  Please see `set xtics` for information about these.
?commands set my2tics
?commands unset my2tics
?commands show my2tics
?set my2tics
?unset my2tics
?show my2tics
?my2tics
?nomy2tics
 Minor tic marks along the y2 (right-hand) axis are controlled by `set
 my2tics`.  Please see `set mxtics`.
?commands set mytics
?commands unset mytics
?commands show mytics
?set mytics
?unset mytics
?show mytics
?mytics
?nomytics
 Minor tic marks along the y axis are controlled by `set mytics`.  Please
 see `set mxtics`.
?commands set mztics
?commands unset mztics
?commands show mztics
?set mztics
?unset mztics
?show mztics
?mztics
?nomztics
 Minor tic marks along the z axis are controlled by `set mztics`.  Please
 see `set mxtics`.
?commands set nonlinear
?set nonlinear
?nonlinear
 Syntax:
       set nonlinear <axis> via f(axis) inverse g(axis)
       unset nonlinear <axis>

This command is similar to the `set link` command except that only one of the
 two linked axes is visible.  The hidden axis remains linear. Coordinates along
 the visible axis are mapped by applying g(x) to hidden axis coordinates.
 f(x) maps the visible axis coordinates back onto the hidden linear axis.
 You must provide both the forward and inverse expressions.

To illustrate how this works, consider the case of a log-scale x2 axis.

set x2ange [1:1000]
       set nonlinear x2 via log10(x) inverse 10**x

This achieves the same effect as `set log x2`.  The hidden axis in this case
 has range [0:3], obtained by calculating [log10(xmin):log10(xmax)].

The transformation functions f() and g() must be defined using a
 dummy variable appropriate to the nonlinear axis:
     axis: x x2   dummy variable x
     axis: y y2   dummy variable y
     axis: z cb   dummy variable z
     axis: r      dummy variable r

?set nonlinear examples
?nonlinear examples
 Example:

set xrange [-3:3]
       set nonlinear x via norm(x) inverse invnorm(x)

This example establishes a probability-scaled ("probit") x axis, such that
 plotting the cumulative normal function Phi(x) produces a straight line plot
 against a linear y axis.

Example:

logit(p) = log(p/(1-p))
       logistic(a) = 1. / (1. + exp(-a))
       set xrange [.001 : .999]
       set nonlinear y via logit(y) inverse logistic(y)
       plot logit(x)

This example establishes a logit-scaled y axis such that plotting logit(x)
 on a linear x axis produces a straight line plot.

Example:

f(x) = (x <= 100) ? x : (x < 500) ? NaN : x-390
       g(x) = (x <= 100) ? x : x+390
       set xrange [0:1000] noextend
       set nonlinear x via f(x) inverse g(x)
       set xtics add (100,500)
       plot sample [x=1:100] x, [x=500:1000] x

This example creates a "broken axis". X coordinates 0-100 are at the left,
 X coordinates 500-1000 are at the right, there is a small gap (10 units)
 between them.  So long as no data points with (100 < x < 500) are plotted,
 this works as expected.
?objects
?commands set object
?commands show object
?set object
?object depthorder
?show object
 The `set object` command defines a single object which will appear in
 subsequent plots. You may define as many objects as you like. Currently the
 supported object types are `rectangle`, `circle`, `ellipse`, and `polygon`.
 Rectangles inherit a default set of style properties (fill, color, border) from
 those set by the command `set style rectangle`, but each object can also be
 given individual style properties. Circles, ellipses, and polygons  inherit the
 fill style from `set style fill`.  Objects to be drawn in 2D plots may be
 defined in any combination of axis, graph, polar, or screen coordinates.

Object specifications in 3D plots cannot use graph coordinates.
 Rectangles and ellipses in 3D plots are limited to screen coordinates.

Syntax:
     set object <index>
         <object-type> <object-properties>
         {front|back|behind|depthorder}
         {clip|noclip}
         {fc|fillcolor <colorspec>} {fs <fillstyle>}
         {default} {lw|linewidth <width>} {dt|dashtype <dashtype>}
     unset object <index>

The options `front`, `back`, `behind` control whether the object is drawn
 before or after the plot itself. See `layers`.
 Setting `front` will draw the object in front of all plot elements, but
 behind any labels that are also marked `front`. Setting `back` will place the
 object behind all plot curves and labels. Setting `behind` will place the
 object behind everything including the axes and `back` rectangles, thus
     set object rectangle from screen 0,0 to screen 1,1 behind
 can be used to provide a colored background for the entire graph or page.

By default, objects are clipped to the graph boundary unless one or more
 vertices are given in screen coordinates.  Setting `noclip` will disable
 clipping to the graph boundary, but will still clip against the screen size.

The fill color of the object is taken from the <colorspec>. `fillcolor`
 may be abbreviated `fc`.  The fill style is taken from <fillstyle>.
 See `colorspec` and `fillstyle`.  If the keyword `default` is given,
 these properties are inherited from the default settings at the time a plot
 is drawn. See `set style rectangle`.
?rectangle
?commands set object rectangle
?commands show object rectangle
?set object rectangle
?show object rectangle
 Syntax:
     set object <index> rectangle
         {from <position> {to|rto} <position> |
          center <position> size <w>,<h> |
          at <position> size <w>,<h>}

The position of the rectangle may be specified by giving the position of two
 diagonal corners (bottom left and top right) or by giving the position of the
 center followed by the width and the height.  In either case the positions
 may be given in axis, graph, or screen coordinates. See `coordinates`.
 The options `at` and `center` are synonyms.

Examples:
     # Force the entire area enclosed by the axes to have background color cyan
     set object 1 rect from graph 0, graph 0 to graph 1, graph 1 back
     set object 1 rect fc rgb "cyan" fillstyle solid 1.0

# Position a red square with lower left at 0,0 and upper right at 2,3
     set object 2 rect from 0,0 to 2,3 fc lt 1

# Position an empty rectangle (no fill) with a blue border
     set object 3 rect from 0,0 to 2,3 fs empty border rgb "blue"

# Return fill and color to the default style but leave vertices unchanged
     set object 2 rect default

Rectangle corners specified in screen coordinates may extend beyond the edge of
 the current graph. Otherwise the rectangle is clipped to fit in the graph.

?ellipse
?commands set object ellipse
?commands show object ellipse
?set object ellipse
?show object ellipse
 Syntax:
     set object <index> ellipse {at|center} <position> size <w>,<h>
         {angle <orientation>} {units xy|xx|yy}
         {<other-object-properties>}

The position of the ellipse is specified by giving the center followed by
 the width and the height (actually the major and minor axes). The keywords
 `at` and `center` are synonyms.  The center position may be given in axis,
 graph, or screen coordinates. See `coordinates`. The major and minor axis
 lengths must be given in axis coordinates.  The orientation of the ellipse
 is specified by the angle between the horizontal axis and the major diameter
 of the ellipse.  If no angle is given, the default ellipse orientation
 will be used instead (see `set style ellipse`).  The `units` keyword
 controls the scaling of the axes of the ellipse. `units xy` means that the
 major axis is interpreted in terms of units along the x axis, while the
 minor axis in that of the y axis. `units xx` means that both axes of the
 ellipses are scaled in the units of the x axis, while `units yy` means
 that both axes are in units of the y axis.
 The default is `xy` or whatever `set style ellipse units` was set to.

NB: If the x and y axis scales are not equal, (e.g. `units xy` is in
 effect) then the major/minor axis ratio will no longer be correct after
 rotation.

Note that `set object ellipse size <2r>,<2r>` does not in general produce
 the same result as `set object circle <r>`.  The circle radius is always
 interpreted in terms of units along the x axis, and will always produce a
 circle even if the x and y axis scales are different and even if the aspect
 ratio of your plot is not 1.  If `units` is set to `xy`, then
 'set object ellipse' interprets the first <2r> in terms of x axis units
 and the second <2r> in terms of y axis units. This will only produce a
 circle if the x and y axis scales are identical and the plot aspect ratio
 is 1.  On the other hand, if `units` is set to `xx` or `yy`, then the
 diameters specified in the 'set object' command will be interpreted in the
 same units, so the ellipse will have the correct aspect ratio, and it will
 maintain its aspect ratio even if the plot is resized.

?circle
?commands set object circle
?commands show object circle
?set object circle
?show object circle
 Syntax:
     set object <index> circle {at|center} <position> size <radius>
         {arc [<begin>:<end>]} {no{wedge}}
         {<other-object-properties>}

The position of the circle is specified by giving the position of the center
 center followed by the radius.  The keywords `at` and `center` are synonyms.
 In 2D plots the position and radius may be given in any coordinate system.
 See `coordinates`. Circles in 3D plots cannot use graph coordinates.
 In all cases the radius is calculated relative to the horizontal scale of the
 axis, graph, or canvas.  Any disparity between the horizontal and vertical
 scaling will be corrected for so that the result is always a circle.
 If you want to draw a circle in plot coordinates (such that it will appear as
 an ellipse if the horizontal and vertical scales are different), use
 `set object ellipse` instead.

By default a full circle is drawn. The optional qualifier `arc` specifies
 a starting angle and ending angle, in degrees, for one arc of the circle.
 The arc is always drawn counterclockwise.

See also `set style circle`, `set object ellipse`.

?polygon
?commands set object polygon
?commands show object polygon
?set object polygon
?show object polygon
 Syntax:
     set object <index> polygon
         from <position> to <position> ... {to <position>}
 or
         from <position> rto <position> ... {rto <position>}

The position of the polygon may be specified by giving the position of a
 sequence of vertices. These may be given in any coordinate system.
 If relative coordinates are used (rto) then the coordinate type must match
 that of the previous vertex.
 See `coordinates`.

Example:
     set object 1 polygon from 0,0 to 1,1 to 2,0
     set object 1 fc rgb "cyan" fillstyle solid 1.0 border lt -1
?polygon depthorder
?set object depthorder
 The option `set object N depthorder` applies to 3D polygon objects only.
 Rather than assigning the object to layer front/back/behind it is included
 in the list of pm3d quadrangles sorted and rendered in order of depth by
 `set pm3d depthorder`.  As with pm3d surfaces, two-sided coloring can be
 generated by specifying the object fillcolor as a linestyle.  In this
 case the ordering of the first three vertices in the polygon determines
 the "side".

If you set this property for an object that is not a 3D polygon it probably
 will not be drawn at all.
?commands set offsets
?commands unset offsets
?commands show offsets
?set offsets
?unset offsets
?show offsets
?offsets
?nooffsets
 Autoscaling sets the x and y axis ranges to match the coordinates of the data
 that is plotted.  Offsets provide a mechanism to expand these ranges to leave
 empty space between the data and the plot borders.  Autoscaling then further
 extends each range to reach the next axis tic unless this has been suppressed
 by `set autoscale noextend` or `set xrange noextend`.  See `noextend`.
 Offsets affect only scaling for the x1 and y1 axes.

Syntax:
       set offsets <left>, <right>, <top>, <bottom>
       unset offsets
       show offsets

Each offset may be a constant or an expression.  Each defaults to 0.
 By default, the left and right offsets are given in units of the first x axis,
 the top and bottom offsets in units of the first y axis.  Alternatively, you
 may specify the offsets as a fraction of the total graph dimension by using the
 keyword "graph". Only "graph" offsets are possible for nonlinear axes.

A positive offset expands the axis range in the specified direction, e.g.
 a positive bottom offset makes ymin more negative.  Negative offsets interact
 badly with autoscaling and clipping.

Example:
       set autoscale noextend
       set offsets graph 0.05, 0, 2, 2
       plot sin(x)

This graph of sin(x) will have y range [-3:3] because the function will be
 autoscaled to [-1:1] and the vertical offsets add 2 at each end of the range.
 The x range will be [-11:10] because the default is [-10:10] and it has been
 expanded to the left by 0.05 of that total range.
?commands set origin
?commands show origin
?set origin
?show origin
?origin
 The `set origin` command is used to specify the origin of a plotting surface
 (i.e., the graph and its margins) on the screen.  The coordinates are given
 in the `screen` coordinate system (see `coordinates` for information about
 this system).

Syntax:
       set origin <x-origin>,<y-origin>
?commands set output
?commands show output
?set output
?show output
?output
?output file
 By default, screens are displayed to the standard output. The `set output`
 command redirects the display to the specified file or device.

Syntax:
       set output {"<filename>"}
       show output

The filename must be enclosed in quotes.  If the filename is omitted, any
 output file opened by a previous invocation of `set output` will be closed
 and new output will be sent to STDOUT.  (If you give the command `set output
 "STDOUT"`, your output may be sent to a file named "STDOUT"!  ["May be", not
 "will be", because some terminals, like `x11` or `wxt`, ignore `set output`.])

When both `set terminal` and `set output` are used together, it is safest to
 give `set terminal` first, because some terminals set a flag which is needed
 in some operating systems.  This would be the case, for example, if the
 operating system needs a separate open command for binary files.

On platforms that support pipes, it may be useful to pipe terminal output.
 For instance,

set output "|lpr -Plaser filename"
       set term png; set output "|display png:-"

On MSDOS machines, `set output "PRN"` will direct the output to the default
 printer.  On VMS, output can be sent directly to any spooled device.
?overflow
?commands set overflow
?commands unset overflow
?set overflow
?unset overflow
?show overflow
 Syntax:
      set overflow {float | NaN | undefined}
      unset overflow

This version of gnuplot supports 64-bit integer arithmetic.
 This means that for values from 2^53 to 2^63 (roughly 10^16 to 10^19)
 integer evaluation preserves more precision than evaluation using IEEE 754
 floating point arithmetic.  However unlike the IEEE floating point
 representation, which sacrifices precision to span a total range of
 roughly [-10^307 : 10^307], integer operations that result in values outside
 the range [-2^63 : 2^63] overflow.  The `set overflow` command lets you
 control what happens in case of overflow.  See options below.

`set overflow` is the same as `set overflow float`. It causes the result to be
 returned as a real number rather than as an integer. This is the default.

The command `unset overflow` causes integer arithmetic overflow to be ignored.
 No error is shown.  This may be desirable if your platform allows only 32-bit
 integer arithmetic and you want to approximate the behaviour of gnuplot
 versions prior to 5.4.

The `reset` command does not affect the state of overflow handling.

Earlier gnuplot versions were limited to 32-bit arithmetic and ignored
 integer overflow.  Note, however, that some built-in operators did not
 use integer arithmetic at all, even when given integer arguments. This
 included the exponentiation operator N**M and the summation operator
 (see `summation`).  These operations now return an integer value when
 given integer arguments, making them potentially susceptible to overflow
 and thus affected by the state of `set overflow`.
?set overflow float
?overflow float
 If an integer arithmetic expression overflows the limiting range,
 [-2^63 : 2^63] for 64-bit integers, the result is returned as a floating
 point value instead.  This is not treated as an error.
 Example:
      gnuplot> set overflow float
      gnuplot> A = 2**62 - 1;  print A, A+A, A+A+A
      4611686018427387903 9223372036854775806 1.38350580552822e+19
?set overflow NaN
?overflow NaN
?overflow nan
 If an integer arithmetic expression overflows the limiting range,
 [-2^63 : 2^63] for 64-bit integers, the result is returned as NaN
 (Not a Number).  This is not treated as an error.
 Example:
      gnuplot> set overflow NaN
      gnuplot> print 10**18, 10**19
      1000000000000000000 NaN
?set overflow undefined
?overflow undefined
 If an integer arithmetic expression overflows the limiting range,
 [-2^63 : 2^63] for 64-bit integers, the result is undefined.
 This is treated as an error.
 Example:
      gnuplot> set overflow undefined
      gnuplot> A = 10**19
                   ^
               undefined value
?set overflow affected_operations
?overflow affected_operations
 The `set overflow` state affects the arithmetic operators
      + - * / **
 and the built-in summation operation `sum`.

All of these operations will return an integer result if all of the arguments
 are integers, so long as no overflow occurs during evaluation.

The `set overflow` state does not affect logical or bit operations
      << >>  | ^ &

If overflow occurs at any point during the course of evaluating of a summation
 `set overflow float` will cause the result to be returned as a real number even
 if the final sum is within the range of integer representation.
?commands set palette
?commands show palette
?set palette
 The palette is a set of colors, usually ordered in the form of one or
 more stepped gradients, used for `pm3d` surfaces and other graph elements
 colored by z value.  Colors in the current palette are automatically mapped
 from plot coordinates z values or an extra data column of gray values.
 Palette colors also can be accessed explicitly in a color specification
 (see `colorspec`)
 *  as a `gray value` also known as `palette fraction` in the range [0:1]
 *  as a `z value` corresponding to the z coordinate of a plot element
 *  as a `cb value` in the range [cbmin:cbmax] (see `set cbrange`)
 The current palette is shown by default in a separate `colorbox` drawn
 next to plots that use plot style `pm3d`. The colorbox can be manually
 selected or disabled. See `set colorbox`.

Syntax:
       set palette
       set palette {
                  { gray | color }
                  { gamma <gamma> }
                  {   rgbformulae <r>,<g>,<b>
                    | defined { ( <gray1> <color1> {, <grayN> <colorN>}... ) }
                    | file '<filename>' {datafile-modifiers}
                    | functions <R>,<G>,<B>
                  }
                  { cubehelix {start <val>} {cycles <val>} {saturation <val>} }
                  { model { RGB | HSV | CMY } }
                  { positive | negative }
                  { nops_allcF | ps_allcF }
                  { maxcolors <maxcolors> }
                }
       show palette
       show palette palette <n> {{float | int}}
       show palette gradient
       show palette fit2rgbformulae
       show palette rgbformulae
       show colornames

`set palette` (i.e. without options) sets up the default values.
 Otherwise, the options can be given in any order.
 `show palette` shows the current palette properties.

`show palette gradient` displays the gradient defining the palette (if
 appropriate).  `show palette rgbformulae` prints the available fixed gray -->
 color transformation formulae.  `show colornames` prints the known color names.

`show palette palette <n>` prints to the screen or to the file given by
 `set print` a table of RGB triplets calculated for the current palette settings
 and a palette having <n> discrete colors.  The default wide table can be
 limited to 3 columns of r,g,b float values [0..1] or integer values [0..255]
 by options float or int, respectively.  This way, the current gnuplot color
 palette can be loaded into other imaging applications, for example Octave.
 Alternatively, the `test palette` command will plot the R,G,B profiles for the
 current palette and leave the profile values in a datablock $PALETTE.

The following options determine the coloring properties.

Figure using this palette can be `gray` or `color`.  For instance, in `pm3d`
 color surfaces the gray of each small spot is obtained by mapping the averaged
 z-coordinate of the 4 corners of surface quadrangles into the range
 [min_z,max_z] providing range of grays [0:1]. This value can be used directly
 as the gray for gray maps. The color map requires a transformation gray -->
 (R,G,B), i.e. a mapping [0:1] --> ([0:1],[0:1],[0:1]).

Basically two different types of mappings can be used:  Analytic formulae to
 convert gray to color, or discrete mapping tables which are interpolated.
 `palette rgbformulae` and `palette functions` use analytic formulae whereas
 `palette defined` and `palette file` use interpolated tables.  `palette
 rgbformulae` reduces the size of postscript output to a minimum.

The command `show palette fit2rgbformulae` finds the best matching `set
 palette rgbformulae` for the current `set palette`. Naturally, it makes sense
 to use it for non-rgbformulae palettes. This command can be found useful
 mainly for external programs using the same rgbformulae definition of palettes
 as gnuplot, like zimg (
           http://zimg.sourceforge.net
 ).

`set palette gray` switches to a gray only palette. `set palette rgbformulae`,
 `set palette defined`, `set palette file` and `set palette functions` switch
 to a color mapping. `set palette color` is an easy way to switch back from the
 gray palette to the last color mapping.

Automatic gamma correction via `set palette gamma <gamma>` can be done for
 gray maps (`set palette gray`) and for the `cubehelix` color palette schemes.
 Gamma = 1 produces a linear ramp of intensity. See `test palette`.

Many terminals support only discrete number of colors (e.g. 256 colors in gif).
 After the default gnuplot linetype colors are allocated, the rest of the
 available colors are by default reserved for pm3d.  Thus a multiplot using
 multiple palettes could fail because the first palette has used all the
 available color positions.  You can mitigate this limitation by using
 `set palette maxcolors <N>` with a reasonably small value of N.
 This option causes N discrete colors to be selected from a continuous palette
 sampled at equally spaced intervals.  If you want unequal spacing of N
 discrete colors, use `set palette defined` instead of a single continuous
 palette.

RGB color space might not be the most useful color space to work in.  For that
 reason you may change the color space `model` to one of `RGB`, `HSV`, `CMY`.
 Using color names for `set palette defined` tables and a color space other than
 RGB will result in funny colors.  All explanation have been written for
 RGB color space, so please note, that `R` can be `H`, or `C`,
 depending on the actual color space (`G` and `B` accordingly).

All values for all color spaces are limited to [0,1].

RGB stands for Red, Green, Blue;  CMY stands for Cyan, Magenta, Yellow;
 HSV stands for Hue, Saturation, Value.
 For more information on color models see:
           http://en.wikipedia.org/wiki/Color_space
 Note: Earlier gnuplot versions accepted YIQ and XYZ color space models also,
 but the implementation was never complete or correct.

?commands set palette rgbformulae
?set palette rgbformulae
?palette rgbformulae
?rgbformulae
 For `rgbformulae` three suitable mapping functions have
 to be chosen.  This is done via `rgbformulae <r>,<g>,<b>`.  The available
 mapping functions are listed by `show palette rgbformulae`.  Default is
 `7,5,15`, some other examples are `3,11,6`, `21,23,3` or `3,23,21`.  Negative
 numbers, like `3,-11,-6`, mean inverted color (i.e.  1-gray passed into the
 formula, see also `positive` and `negative` options below).

Some nice schemes in RGB color space
    7,5,15   ... traditional pm3d (black-blue-red-yellow)
    3,11,6   ... green-red-violet
    23,28,3  ... ocean (green-blue-white); try also all other permutations
    21,22,23 ... hot (black-red-yellow-white)
    30,31,32 ... color printable on gray (black-blue-violet-yellow-white)
    33,13,10 ... rainbow (blue-green-yellow-red)
    34,35,36 ... AFM hot (black-red-yellow-white)

A full color palette in HSV color space
    3,2,2    ... red-yellow-green-cyan-blue-magenta-red

Please note that even if called `rgbformulae` the formulas might actually
 determine the <H>,<S>,<V> or <X>,<Y>,<Z> or ... color components as usual.

Use `positive` and `negative` to invert the figure colors.

Note that it is possible to find a set of the best matching rgbformulae for any
 other color scheme by the command
    show palette fit2rgbformulae
?commands set palette defined
?set palette defined
?palette defined
 Gray-to-rgb mapping can be manually set by use of `palette defined`:
 A color gradient is defined and used to give the rgb values.  Such a gradient
 is a piecewise linear mapping from gray values in [0,1] to the RGB space
 [0,1]x[0,1]x[0,1].  You must specify the gray values and the corresponding RGB
 values between which linear interpolation will be done.

Syntax:
       set palette  defined { ( <gray1> <color1> {, <grayN> <colorN>}... ) }

<grayX> are gray values which are mapped to [0,1] and <colorX> are the
 corresponding rgb colors.  The color can be specified in three different
 ways:

<color> :=  { <r> <g> <b> | '<color-name>' | '#rrggbb' }

Either by three numbers (each in [0,1]) for red, green and blue, separated by
 whitespace, or the name of the color in quotes or X style color specifiers
 also in quotes.  You may freely mix the three types in a gradient definition,
 but the named color "red" will be something strange if RGB is not selected
 as color space.  Use `show colornames` for a list of known color names.

Please note, that even if written as <r>, this might actually be the
 <H> component in HSV color space depending on the selected color model.

The <gray> values have to form an ascending sequence of real numbers; the
 sequence will be automatically rescaled to [0,1].

`set palette defined` (without a gradient definition in braces) switches to
 RGB color space and uses a preset full-spectrum color gradient.
 Use `show palette gradient` to display the gradient.

Examples:

To produce a gray palette (useless but instructive) use:
       set palette model RGB
       set palette defined ( 0 "black", 1 "white" )

To produce a blue yellow red palette use (all equivalent):
       set palette defined ( 0 "blue", 1 "yellow", 2 "red" )
       set palette defined ( 0 0 0 1, 1 1 1 0, 2 1 0 0 )
       set palette defined ( 0 "#0000ff", 1 "#ffff00", 2 "#ff0000" )

To produce some rainbow-like palette use:
       set palette defined ( 0 "blue", 3 "green", 6 "yellow", 10 "red" )

Full color spectrum within HSV color space:
       set palette model HSV
       set palette defined ( 0 0 1 1, 1 1 1 1 )
       set palette defined ( 0 0 1 0, 1 0 1 1, 6 0.8333 1 1, 7 0.8333 0 1)

Approximate the default palette used by MATLAB:
       set pal defined (1 '#00008f', 8 '#0000ff', 24 '#00ffff', \
                        40 '#ffff00', 56 '#ff0000', 64 '#800000')

To produce a palette with only a few, equally-spaced colors:
       set palette model RGB maxcolors 4
       set palette defined ( 0 "yellow", 1 "red" )

'Traffic light' palette (non-smooth color jumps at gray = 1/3 and 2/3).
       set palette model RGB
       set palette defined (0 "dark-green", 1 "green", \
                            1 "yellow",     2 "dark-yellow", \
                            2 "red",        3 "dark-red" )

?commands set palette functions
?set palette functions
?palette functions
 Use `set palette functions <Rexpr>, <Gexpr>, <Bexpr>` to define three formulae
 for the R(gray), G(gray) and B(gray) mapping.  The three formulae may depend
 on the variable `gray` which will take values in [0,1] and should also
 produce values in [0,1].
 Please note that <Rexpr> might be a formula for the H-value if HSV color
 space has been chosen (same for all other formulae and color spaces).

Examples:

To produce a full color palette use:
       set palette model HSV functions gray, 1, 1

A nice black to gold palette:
       set palette model RGB functions 1.1*gray**0.25, gray**0.75, 0

A gamma-corrected black and white palette
       gamma = 2.2
       color(gray) = gray**(1./gamma)
       set palette model RGB functions color(gray), color(gray), color(gray)
?commands set palette gray
?set palette gray
?set palette grey
?palette gray
 `set palette gray` switches to a grayscale palette shading from 0.0 = black
 to 1.0 = white.  `set palette color` is an easy way to switch back from the
 gray palette to the last color mapping.
?commands set palette cubehelix
?set palette cubehelix
?cubehelix
 The "cubehelix" option defines a family of palettes in which color (hue) varies
 along the standard color wheel while at the same time the net intensity
 increases monotonically as the gray value goes from 0 to 1.
       D A Green (2011) http://arxiv.org/abs/1108.5083
 `start` defines the starting point along the color wheel in radians.
 `cycles` defines how many color wheel cycles span the palette range.
 Larger values of `saturation` produce more saturated color; saturation > 1
 may lead to clipping of the individual RGB components and to intensity
 becoming non-monotonic. The palette is also affected by `set palette gamma`.
 The default values are
       set palette cubehelix start 0.5 cycles -1.5 saturation 1
       set palette gamma 1.5

?commands set palette file
?set palette file
?palette file
 `set palette file` is basically a `set palette defined (<gradient>)` where
 <gradient> is read from a datafile.  Either 4 columns (gray,R,G,B) or
 just three columns (R,G,B) have to be selected via the `using` data file
 modifier.  In the three column case, the line number will be used as gray.
 The gray range is automatically rescaled to [0,1].  The file is read as a
 normal data file, so all datafile modifiers can be used.
 Please note, that `R` might actually be e.g. `H` if HSV color space is
 selected.

As usual <filename> may be `'-'` which means that the data follow the command
 inline and are terminated by a single `e` on a line of its own.

Use `show palette gradient` to display the gradient.

Examples:

Read in a palette of RGB triples each in range [0,255]:
       set palette file 'some-palette' using ($1/255):($2/255):($3/255)

Equidistant rainbow (blue-green-yellow-red) palette:
       set palette model RGB file "-"
       0 0 1
       0 1 0
       1 1 0
       1 0 0
       e

Binary palette files are supported as well, see `binary general`. Example:
 put 64 triplets of R,G,B doubles into file palette.bin and load it by
       set palette file "palette.bin" binary record=64 using 1:2:3

?commands set palette gamma-correction
?set palette gamma-correction
?palette gamma-correction
?gamma-correction
 For gray mappings gamma correction can be turned on by `set palette gamma
 <gamma>`.  <gamma> defaults to 1.5 which is quite suitable for most
 terminals.

The gamma correction is applied to the cubehelix color palette family, but not
 to other palette coloring schemes. However, you may easily implement gamma
 correction for explicit color functions.

Example:
       set palette model RGB
       set palette functions gray**0.64, gray**0.67, gray**0.70

To use gamma correction with interpolated gradients specify intermediate
 gray values with appropriate colors.  Instead of

set palette defined ( 0 0 0 0, 1 1 1 1 )

use e.g.

set palette defined ( 0 0 0 0, 0.5 .73 .73 .73, 1 1 1 1 )

or even more intermediate points until the linear interpolation fits the
 "gamma corrected" interpolation well enough.

?commands set palette postscript
?set palette postscript
 In order to reduce the size of postscript files, the gray value and not all
 three calculated r,g,b values are written to the file.  Therefore the
 analytical formulae are coded directly in the postscript language as a header
 just before the pm3d drawing, see /g and /cF definitions.  Usually, it makes
 sense to write therein definitions of only the 3 formulae used.  But for
 multiplot or any other reason you may want to manually edit the
 transformations directly in the postscript file.  This is the default option
 `nops_allcF`.  Using the option `ps_allcF` writes postscript definitions of
 all formulae.  This you may find interesting if you want to edit the
 postscript file in order to have different palettes for different surfaces
 in one graph.  Well, you can achieve this functionality by `multiplot` with
 fixed `origin` and `size`.

If you are writing a pm3d surface to a postscript file, it may be possible to
 reduce the file size by up to 50% by the enclosed awk script
 `pm3dCompress.awk`.  If the data lies on a rectangular grid, even greater
 compression may be possible using the script `pm3dConvertToImage.awk`.
 Usage:
     awk -f pm3dCompress.awk thefile.ps >smallerfile.ps
     awk -f pm3dConvertToImage.awk thefile.ps >smallerfile.ps

?commands set parametric
?commands unset parametric
?commands show parametric
?set parametric
?unset parametric
?show parametric
?parametric
?noparametric
 The `set parametric` command changes the meaning of `plot` (`splot`) from
 normal functions to parametric functions.  The command `unset parametric`
 restores the plotting style to normal, single-valued expression plotting.

Syntax:
       set parametric
       unset parametric
       show parametric

For 2D plotting, a parametric function is determined by a pair of parametric
 functions operating on a parameter.  An example of a 2D parametric function
 would be `plot sin(t),cos(t)`, which draws a circle (if the aspect ratio is
 set correctly---see `set size`).  `gnuplot` will display an error message if
 both functions are not provided for a parametric `plot`.

For 3D plotting, the surface is described as x=f(u,v), y=g(u,v), z=h(u,v).
 Therefore a triplet of functions is required.  An example of a 3D parametric
 function would be `cos(u)*cos(v),cos(u)*sin(v),sin(u)`, which draws a sphere.
 `gnuplot` will display an error message if all three functions are not
 provided for a parametric `splot`.

The total set of possible plots is a superset of the simple f(x) style plots,
 since the two functions can describe the x and y values to be computed
 separately.  In fact, plots of the type t,f(t) are equivalent to those
 produced with f(x) because the x values are computed using the identity
 function.  Similarly, 3D plots of the type u,v,f(u,v) are equivalent to
 f(x,y).

Note that the order the parametric functions are specified is xfunction,
 yfunction (and zfunction) and that each operates over the common parametric
 domain.

Also, the `set parametric` function implies a new range of values.  Whereas
 the normal f(x) and f(x,y) style plotting assume an xrange and yrange (and
 zrange), the parametric mode additionally specifies a trange, urange, and
 vrange.  These ranges may be set directly with `set trange`, `set urange`,
 and `set vrange`, or by specifying the range on the `plot` or `splot`
 commands.  Currently the default range for these parametric variables is
 [-5:5].  Setting the ranges to something more meaningful is expected.
?paxis
?commands set paxis
?set paxis
?show paxis
 Syntax:
       set paxis <axisno> {range <range-options> | tics <tic-options>}
       set paxis <axisno> label <label-options> { offset <radial-offset> }
       show paxis <axisno> {range | tics}
 The `set paxis` command is equivalent to the `set xrange` and `set xtics`
 commands except that it acts on one of the axes p1, p2, ... used in parallel
 axis plots and spiderplots.  See `parallelaxes`, `set xrange`, and `set xtics`.
 The normal options to the range and tics commands are accepted although not
 all options make sense for parallel axis plots.

`set paxis <axisno> label <label-options>` is relevant to spiderplots but
 ignored otherwise.  Axes of a parallel axis plot can be labeled using the
 `title` option of the plot command, which generates an xtic label.
 Note that this may require also `set xtics`.

The axis linetype properties are controlled using `set style parallelaxis`.
?pixmap
?set pixmap
?unset pixmaps
?show pixmaps
?commands set pixmap
 Syntax:
       set pixmap <index> "filename" at <position>
                  {width <w> | height <h> | size <w>,<h>}
                  {front|back|behind} {center}
       show pixmaps
       unset pixmaps
       unset pixmap <index>

The `set pixmap` command is similar to `set object` in that it defines an
 object that will appear on subsequent plots. The rectangular array of
 red/green/blue/alpha values making up the pixmap are read from a png, jpeg, 
 or gif file.  The position and extent occupied by the pixmap in the gnuplot
 output may be specified in any coordinate system (see `coordinates`).
 The coordinates given by `at <position>` refer to the lower left
 corner of the pixmap unless keyword `center` is present.

If the x-extent of the rendered pixmap is set using `width <x-extent>` the
 aspect ratio of the original image is retained and neither the aspect ratio
 nor the orientation of the pixmap changes with axis scaling or rotation.
 Similarly if the y-extent is set using `height <y-extent>`.  If both the
 x-extent and y-extent are given using `size <x-extent> <y-extent>` this
 overrides the original aspect ratio.  If no size is set then the original
 size in pixels is used (the effective size is then terminal-dependent).

Pixmaps are not clipped to the border of the plot.  As an exception to the
 general behaviour of objects and layers, a pixmap assigned to layer `behind`
 is rendered for only the first plot in a multiplot.  This allows all panels
 in a multiplot to share a single background pixmap.

Examples:
       # Use a gradient as the background for all plotting
       # Both x and y will be resized to fill the entire canvas
       set pixmap 1 "gradient.png"
       set pixmap 1 at screen 0, 0 size screen 1, 1 behind

# Place a logo at the lower right of each page plotted
       set pixmap 2 "logo.jpg"
       set pixmap 2 at screen 0.95, 0 width screen 0.05 behind

# Place a small image at some 3D coordinate
       # It will move as if attached to the surface being plotted
       # but will always face forward and remain upright
       set pixmap 3 "image.png" at my_x, my_y, f(my_x,my_y) width screen .05
       splot f(x,y)
?commands show plot
?show plot
 The `show plot` command shows the current plotting command as it results
 from the last `plot` and/or `splot` and possible subsequent `replot` commands.

In addition, the `show plot add2history` command adds this current plot
 command into the `history`. It is useful if you have used `replot` to add
 more curves to the current plot and you want to edit the whole command now.
?commands set pm3d
?commands show pm3d
?set pm3d
?show pm3d
?pm3d
 pm3d is an `splot` style for drawing palette-mapped 3d and 4d data as
 color/gray maps and surfaces.  It allows plotting gridded or non-gridded data
 without preprocessing. pm3d style options also affect solid-fill polygons
 used to construct other 3D plot elements.

Syntax (the options can be given in any order):
       set pm3d {
                  { at <position> }
                  { interpolate <steps/points in scan, between scans> }
                  { scansautomatic | scansforward | scansbackward
                                   | depthorder {base} }
                  { flush { begin | center | end } }
                  { ftriangles | noftriangles }
                  { clip {z} | clip1in | clip4in }
                  { {no}clipcb }
                  { corners2color
                    { mean|geomean|harmean|rms|median|min|max|c1|c2|c3|c4 }
                  }
                  { {no}lighting
                    {primary <fraction>} {specular <fraction>} {spec2 <fraction>}
                  }
                  { border {<linestyle-options>}}
                  { implicit | explicit }
                  { map }
                }
       show pm3d
       unset pm3d

Note that pm3d plots are plotted sequentially in the order given in the
 splot command. Thus earlier plots may be obscured by later plots.
 To avoid this you can use the `depthorder` scan option.

The pm3d surfaces can be projected onto the `top` or `bottom` of the view box.
 See `pm3d position`.
 The following command draws three color surfaces at different altitudes:
       set border 4095
       set pm3d at s
       splot 10*x with pm3d at b, x*x-y*y, x*x+y*y with pm3d at t

See also help for `set palette`, `set cbrange`, `set colorbox`,
 and the demo file `demo/pm3d.dem`.
?pm3d implicit
?pm3d explicit
 A pm3d color surface is drawn if the splot command specifies `with pm3d`,
 if the data or function `style` is set to pm3d globally, or if the pm3d mode is
 `set pm3d implicit`.  In the latter two cases, the pm3d surface is draw in
 addition to the mesh produced by the style specified in the plot command. E.g.
       splot 'fred.dat' with lines, 'lola.dat' with lines
 would draw both a mesh of lines and a pm3d surface for each data set.
 If the option `explicit` is on (or `implicit` is off) only plots specified
 by the `with pm3d` attribute are plotted with a pm3d surface, e.g.:
       splot 'fred.dat' with lines, 'lola.dat' with pm3d
 would plot 'fred.dat' with lines (only) and 'lola.dat' with a pm3d surface.

On gnuplot start-up, the mode is `explicit`. For historical and compatibility
 reasons, the commands `set pm3d;` (i.e. no options) and `set pm3d at X ...`
 (i.e.  `at` is the first option) change the mode to `implicit`.
 The command `set pm3d;` sets other options to their default state.

If you set the default data or function style to `pm3d`, e.g.:
       set style data pm3d
 then the options `implicit` and `explicit` have no effect.
?pm3d algorithm

Let us first describe how a map/surface is drawn.  The input data come from an
 evaluated function or from an `splot data file`.  Each surface consists of a
 sequence of separate scans (isolines).  The pm3d algorithm fills the region
 between two neighbouring points in one scan with another two points in the
 next scan by a gray (or color) according to z-values (or according to an
 additional 'color' column, see help for `using`) of these 4 corners; by default
 the 4 corner values are averaged, but this can be changed by the option
 `corners2color`.  In order to get a reasonable surface, the neighbouring scans
 should not cross and the number of points in the neighbouring scans should not
 differ too much; of course, the best plot is with scans having same number of
 points.  There are no other requirements (e.g. the data need not be gridded).
 Another advantage is that the pm3d algorithm does not draw anything outside of
 the input (measured or calculated) region.

Surface coloring works with the following input data:

1. splot of function or of data file with one or three data columns: The
 gray/color scale is obtained by mapping the averaged (or `corners2color`)
 z-coordinate of the four corners of the above-specified quadrangle into the
 range [min_color_z,max_color_z] of `zrange` or `cbrange` providing a gray value
 in the range [0:1].  This value can be used directly as the gray for gray maps.
 The normalized gray value can be further mapped into a color---see `set palette`
 for the complete description.

2. splot of data file with two or four data columns: The gray/color value is
 obtained by using the last-column coordinate instead of the z-value, thus
 allowing the color and the z-coordinate be mutually independent.  This can be
 used for 4d data drawing.

Other notes:

1. The term 'scan' referenced above is used more among physicists than the
 term 'iso_curve' referenced in gnuplot documentation and sources.  You measure
 maps recorded one scan after another scan, that's why.

2. The 'gray' or 'color' scale is a linear mapping of a continuous variable
 onto a smoothly varying palette of colors. The mapping is shown in a
 rectangle next to the main plot. This documentation refers to this as a
 "colorbox", and refers to the indexing variable as lying on the colorbox axis.
 See `set colorbox`, `set cbrange`.
?lighting
?pm3d lighting
?pm3d nolighting
?set pm3d lighting
 By default the colors assigned to pm3d objects are not dependent on orientation
 or viewing angle. This state corresponds to `set pm3d nolighting`.
 The command `set pm3d lighting` selects a simple lighting model consisting of a
 single fixed source of illumination contributing 50% of the overall lighting.
 The strength of this light relative to the ambient illumination can be adjusted
 by `set pm3d lighting primary <fraction>`.  Inclusion of specular highlighting
 can be adjusted by setting a fractional contribution:
      set pm3d lighting primary 0.50 specular 0.0   # no highlights
      set pm3d lighting primary 0.50 specular 0.6   # strong highlights
 Solid-color pm3d surfaces tend to look very flat without specular highlights.
 Since the highlights from a single source only affect one side of the surface,
 a second spotlight source may be desirable to add specular highlights from the
 opposite direction.  This is controlled by "spec2 <contribution>".
 EXPERIMENTAL (details may change in a future version): The second spotlight is
 a pure red light source that by default contributes nothing (spec2 0.0).
 See also hidden_compare.dem
 (comparison of hidden3d and pm3d treatment of solid-color surfaces)
?pm3d position
?set pm3d position
 Color surface can be drawn at the base or top (then it is a gray/color planar
 map) or at z-coordinates of surface points (gray/color surface).  This is
 defined by the `at` option with a string of up to 6 combinations of `b`, `t`
 and `s`. For instance, `at b` plots at bottom only, `at st` plots firstly
 surface and then top map, while `at bstbst` will never by seriously used.

Colored quadrangles are plotted one after another.  When plotting surfaces
 (`at s`), the later quadrangles overlap (overdraw) the previous ones.
 (Gnuplot is not virtual reality tool to calculate intersections of filled
 polygon meshes.)  You may try to switch between `scansforward` and
 `scansbackward` to force the first scan of the data to be plotted first or
 last.  The default is `scansautomatic` where gnuplot makes a guess about scans
 order.  On the other hand, the `depthorder` option completely reorders the
 quadrangles. The rendering is performed after a depth sorting, which allows to
 visualize even complicated surfaces; see `pm3d depthorder` for more details.
?pm3d scanorder
?pm3d depthorder
?pm3d flush
?pm3d ftriangles
?set pm3d scanorder
?set pm3d depthorder
?set pm3d flush
?set pm3d ftriangles
?depthorder
?scansforward
?scansautomatic
?scansbackward
      set pm3d {scansautomatic | scansforward | scansbackward | depthorder}

By default the quadrangles making up a pm3d solid surface are rendered in the
 order they are encountered along the surface grid points.  This order may be
 controlled by the options `scansautomatic`|`scansforward`|`scansbackward`.
 These scan options are not in general compatible with hidden-surface removal.

If two successive scans do not have same number of points, then it has to be
 decided whether to start taking points for quadrangles from the beginning of
 both scans (`flush begin`), from their ends (`flush end`) or to center them
 (`flush center`).  Note, that `flush (center|end)` are incompatible with
 `scansautomatic`: if you specify `flush center` or `flush end` and
 `scansautomatic` is set, it is silently switched to `scansforward`.

If two subsequent scans do not have the same number of points, the option
 `ftriangles` specifies whether color triangles are drawn at the scan tail(s)
 where there are not enough points in either of the scans. This can be used to
 draw a smooth map boundary.

Gnuplot does not do true hidden surface removal for solid surfaces, but often
 it is sufficient to render the component quadrangles in order from furthest
 to closest.  This mode may be selected using the option
       set pm3d depthorder
 Note that the global option `set hidden3d` does not affect pm3d surfaces.

The `depthorder` option by itself tends to produce bad results when
 applied to the long thin rectangles generated by `splot with boxes`.
 It works better to add the keyword `base`, which performs the depth sort
 using the intersection of the box with the plane at z=0.  This type of
 plot is further improved by adding a lighing model.
 Example:
      set pm3d depthorder base
      set pm3d lighting
      set boxdepth 0.4
      splot $DATA using 1:2:3 with boxes

?pm3d clipping
?set pm3d clipping
?clipcb
?clip1in
?clip4in
?pm3d clipcb
?noclipcb
?pm3d noclipcb
 Syntax:
      set pm3d {clip {z} | clip1in | clip4in}
      set pm3d {no}clipcb

The component quadrangles of a pm3d surface or other 3D object are by default
 smoothly clipped against the current zrange.  This is a change from earlier 
 gnuplot versions.

Alternatively, surfaces can be clipped by rendering whole quadrangles but only
 those with all 4 corners in-range on x, y, and z (`set pm3d clip4in`), or only
 those with at least one corner in-range on x, y, and z (`set pm3d clip1in`).
 The options `clip`, `clip1in`, and `clip4in` are mutually exclusive.

Separate from clipping based on spatial x, y, and z coordinates, quadrangles
 can be rendered or not based on extreme palette color values.
 `clipcb`: (default) palette color values < cbmin are clipped to equal cbmin;
 palette color values > cbmax are clipped to equal cbmax.
 `noclipcb`: quadrangles with color value outside cbrange are not drawn at all.

?pm3d color_assignment
 The default pm3d coloring assigns an individual color to each quadrangle of
 the surface grid.  For alternative coloring schemes that assign uniform color to
 the entire surface, see `pm3d fillcolor`.

A single gray/color value (i.e. not a gradient) is assigned to each quadrangle.
 This value is calculated from the z-coordinates the four quadrangle corners
 according to `corners2color <option>`.  The value is then used to select a
 color from the current palette.  See `set palette`.
 It is not possible to change palettes inside a single `splot` command.

If a fourth column of data is provided, the coloring of individual quadrangles
 works as above except that the color value is distinct from the z value.
 As a separate coloring option, the fourth data column may provide instead
 an RGB color. See `rgbcolor variable`. In this case the plotting command
 must be

splot ... using 1:2:3:4 with pm3d lc rgb variable

Notice that ranges of z-values and color-values for surfaces are adjustable
 independently by `set zrange`, `set cbrange`, `set log z`, `set log cb`, etc.
?pm3d corners2color
?set pm3d corners2color
?corners2color
 The color of each quadrangle in a pm3d surface is assigned based on the color
 values of its four bounding vertices.
 The options 'mean' (default), 'geomean', 'harmean, 'rms', and 'median' produce
 various kinds of surface color smoothing, while options 'min' and 'max' choose
 minimal or maximal value, respectively. This may not be desired for pixel
 images or for maps with sharp and intense peaks, in which case the options
 'c1', 'c2', 'c3' or 'c4' can be used instead to assign the quadrangle color
 based on the z-coordinate of only one corner.  Some experimentation may be
 needed to determine which corner corresponds to 'c1', as the orientation
 depends on the drawing direction.  Because the pm3d algorithm does not extend
 the colored surface outside the range of the input data points, the 'c<j>'
 coloring options will result in pixels along two edges of the grid not
 contributing to the color of any quadrangle.  For example, applying the pm3d
 algorithm to the 4x4 grid of data points in script `demo/pm3d.dem` (please have
 a look) produces only (4-1)x(4-1)=9 colored rectangles.
?set pm3d hidden3d
?pm3d hidden3d
?set pm3d border
?pm3d border
 The option `set pm3d border {line-properties}` draws bounding lines around each
 quadrangle as it is rendered. Normally this is used in conjunction with the
 `depthorder` option to approximate hidden line removal.
 Note that the global option `set hidden3d` has no effect on pm3d plots.
 Default line properties (color, width) optionally follow the keyword `border`.
 These defaults can be overridden later in an splot command.

Example of recommended usage:

set pm3d at s depthorder border lw 0.2 lt black
       unset hidden3d
       unset surf
       splot x*x+y*y linecolor rgb "blue"   # otherwise it would be black

?pm3d fillcolor
      splot FOO with pm3d fillcolor <colorspec>

Plot style `with pm3d` accepts an optional fillcolor in the splot command.
 This specification is applied to the entire pm3d surface.  See `colorspec`.
 Most fillcolor specifications will result in a single solid color, which is
 hard to interpret visually unless there is also a lighting model present to
 distinguish surface components based on orientation.  See `pm3d lighting`.

There are a few special cases.  `with pm3d fillcolor palette` would produce
 the same result as the default pm3d palette-based coloring, and is therefore
 not a useful option. `with pm3d fillcolor linestyle N` is more interesting.
 This variant assigns distinct colors to the top and bottom of the pm3d
 surface, similar to the color scheme used by gnuplot's `hidden3d` mode.
 Linestyle N is used for the top surface; linestyle N+1 for the bottom surface.
 Note that "top" and "bottom" depend on the scan order, so that the colors are
 inverted for `pm3d scansbackward` as compared to `pm3d scansforward`.
 This coloring option works best with `pm3d depthorder`, however, which
 unfortunately does not allow you to control the scan order so you may have
 to instead swap the colors defined for linestyles N and N+1.
?set pm3d interpolate
?pm3d interpolate
 The option `interpolate m,n` will interpolate between grid points to generate
 a finer mesh.  For data files, this smooths the color surface and enhances the
 contrast of spikes in the surface.  When working with functions, interpolation
 makes little sense.  It would usually make more sense to increase `samples` and
 `isosamples`.

For positive m and n, each quadrangle or triangle is interpolated m-times and
 n-times in the respective direction.  For negative m and n, the interpolation
 frequency is chosen so that there will be at least |m| and |n| points drawn;
 you can consider this as a special gridding function.

Note: `interpolate 0,0`, will automatically choose an optimal number of
 interpolated surface points.

Note: Currently color interpolation is always linear, even if corners2color
 is set to a nonlinear scheme such as the geometric mean.
?set pm3d deprecated_options
?pm3d deprecated_options
?set pm3d map
?pm3d map
?map
 The deprecated option `set pm3d map` was equivalent to
 `set pm3d at b; set view map; set style data pm3d; set style func pm3d;`

The deprecated option `set pm3d hidden3d N` was equivalent to
 `set pm3d border ls N`.
?commands set pointintervalbox
?set pointintervalbox
?pointintervalbox
 The `pointinterval` and `pointnumber` properties of a line type are used only
 in plot style `linespoints`.  A negative value of pointinterval or pointnumber,
 e.g. -N, means that before the selected set of point symbols are drawn a box
 (actually circle) behind each point symbol is blanked out by filling with the
 background color.  The command `set pointintervalbox` controls the radius of
 this blanked-out region.  It is a multiplier for the default radius, which is
 equal to the point size.
?commands set pointsize
?commands show pointsize
?set pointsize
?show pointsize
?pointsize
 The `set pointsize` command scales the size of the points used in plots.

Syntax:
       set pointsize <multiplier>
       show pointsize

The default is a multiplier of 1.0.  Larger pointsizes may be useful to
 make points more visible in bitmapped graphics.

The pointsize of a single plot may be changed on the `plot` command.
 See `plot with` for details.

Please note that the pointsize setting is not supported by all terminal
 types.
?commands set polar
?commands unset polar
?commands show polar
?set polar
?unset polar
?show polar
?polar
?nopolar
 The `set polar` command changes the meaning of the plot from rectangular
 coordinates to polar coordinates.

Syntax:
       set polar
       unset polar
       show polar

In polar coordinates, the dummy variable (t) represents an angle theta.
 The default range of t is [0:2*pi], or [0:360] if degree units have been
 selected (see `set angles`).

The command `unset polar` changes the meaning of the plot back to the default
 rectangular coordinate system.

The `set polar` command is not supported for `splot`s.  See the `set mapping`
 command for similar functionality for `splot`s.

While in polar coordinates the meaning of an expression in t is really
 r = f(t), where t is an angle of rotation.  The trange controls the domain
 (the angle) of the function. The r, x and y ranges control the extent of the
 graph in the x and y directions.  Each of these ranges, as well as the
 rrange, may be autoscaled or set explicitly.  For details, see `set rrange`
 and `set xrange`.

Example:
       set polar
       plot t*sin(t)
       set trange [-2*pi:2*pi]
       set rrange [0:3]
       plot t*sin(t)

The first `plot` uses the default polar angular domain of 0 to 2*pi.  The
 radius and the size of the graph are scaled automatically.  The second `plot`
 expands the domain, and restricts the size of the graph to the area within
 3 units of the origin.  This has the effect of limiting x and y to [-3:3].

By default polar plots are oriented such that theta=0 is at the far right,
 with theta increasing counterclockwise.  You can change both the origin and
 the sense explicitly.  See `set theta`.

You may want to `set size square` to have `gnuplot` try to make the aspect
 ratio equal to unity, so that circles look circular.  Tic marks around the
 perimeter can be specified using `set ttics`.
 See also
 polar demos (polar.dem)
 and
 polar data plot (poldat.dem).
?commands set print
?commands show print
?set print
?show print
 The `set print` command redirects the output of the `print` command to a file.

Syntax:
       set print
       set print "-"
       set print "<filename>" [append]
       set print "|<shell_command>"
       set print $datablock [append]

`set print` with no parameters restores output to <STDERR>.  The <filename>
 "-" means <STDOUT>. The `append` flag causes the file to be opened in append
 mode.  A <filename> starting with "|" is opened as a pipe to the
 <shell_command> on platforms that support piping.

The destination for `print` commands can also be a named data block. Data
 block names start with '$', see also `inline data`.
 When printing a string to a data block, embedded newline characters are
 expanded to generate multiple data block entries.  This is a CHANGE.
?commands set psdir
?commands show psdir
?set psdir
?show psdir
?psdir
 The `set psdir <directory>` command controls the search path used by the
 postscript terminal to find prologue.ps and character encoding files.
 You can use this mechanism to switch between different sets of
 locally-customized prolog files.
 The search order is
       1) The directory specified by `set psdir`, if any
       2) The directory specified by environmental variable GNUPLOT_PS_DIR
       3) A built-in header or one from the default system directory
       4) Directories set by `set loadpath`
?commands set raxis
?raxis
?set raxis
?unset raxis
 The commands `set raxis` and `unset raxis` toggle whether the polar axis
 is drawn separately from grid lines and the x axis.  If the minimum of the
 current rrange is non-zero (and not autoscaled), then a white circle is drawn
 at the center of the polar plot to indicate that the plot lines and axes do
 not reach 0.  The axis line is drawn using the same line type as the plot
 border.  See `polar`, `rrange`, `rtics`, `rlabel`, `set grid`.
?commands set rgbmax
?set rgbmax
?rgbmax
?unset rgbmax
 Syntax:
      set rgbmax {1.0 | 255}
      unset rgbmax
 The red/green/blue color components of an rgbimage plot are by default
 interpreted as integers in the range [0:255].  `set rgbmax 1.0` tells the
 program that data values used to generate the color components of a plot
 with `rgbimage` or `rgbalpha` are floating point values in the range [0:1].
 `unset rgbmax` returns to the default integer range [0:255].
?commands set rlabel
?rlabel
?set rlabel
?unset rlabel
 This command places a label above the r axis. The label will be drawn whether
 or not the plot is in polar mode.  See `set xlabel` for additional keywords.
?commands set rmargin
?set rmargin
?rmargin
 The command `set rmargin` sets the size of the right margin.
 Please see `set margin` for details.
?commands set rrange
?commands show rrange
?set rrange
?show rrange
?rrange
 The `set rrange` command sets the range of the radial coordinate for a graph
 in polar mode.  This has the effect of setting both xrange and yrange as well.
 The resulting xrange and yrange are both [-(rmax-rmin) : +(rmax-rmin)].
 However if you later change the x or y range, for example by zooming, this does
 not change rrange, so data points continue to be clipped against rrange.
 Unlike other axes, autoscaling the raxis always results in rmin = 0.
 The `reverse` autoscaling flag is ignored.
 Note: Setting a negative value for rmin may produce unexpected results.
?commands set rtics
?commands show rtics
?set rtics
?show rtics
?rtics
 The `set rtics` command places tics along the polar axis.  The tics and labels
 are drawn to the right of the origin. The `mirror` keyword causes them to be
 drawn also to the left of the origin. See `polar`, `set xtics`, and
 `set mxtics` for discussion of keywords.
?commands set samples
?commands show samples
?set samples
?show samples
?samples
 The default sampling rate of functions, or for interpolating data, may be
 changed by the `set samples` command.  To change the sampling range for a
 particular plot, see `plot sampling`.

Syntax:
       set samples <samples_1> {,<samples_2>}
       show samples

By default, sampling is set to 100 points.  A higher sampling rate will
 produce more accurate plots, but will take longer.  This parameter has no
 effect on data file plotting unless one of the interpolation/approximation
 options is used.  See `plot smooth` re 2D data and `set cntrparam` and
 `set dgrid3d` re 3D data.

When a 2D graph is being done, only the value of <samples_1> is relevant.

When a surface plot is being done without the removal of hidden lines, the
 value of samples specifies the number of samples that are to be evaluated for
 the isolines.  Each iso-v line will have <sample_1> samples and each iso-u
 line will have <sample_2> samples.  If you only specify <samples_1>,
 <samples_2> will be set to the same value as <samples_1>.  See also
 `set isosamples`.
?commands set size
?commands show size
?set size
?show size
?size
?aspect ratio
?set size square
?set size ratio
?ratio
?square
 Syntax:
       set size {{no}square | ratio <r> | noratio} {<xscale>,<yscale>}
       show size

The <xscale> and <yscale> values are scale factors for the size of the plot,
 which includes the graph, labels, and margins.

Important note:
       In earlier versions of gnuplot, some terminal types used the values from
       `set size` to control also the size of the output canvas; others did not.
       Almost all terminals now follow the following convention:

`set term <terminal_type> size <XX>, <YY>` controls the size of the output
 file, or `canvas`. Please see individual terminal documentation for allowed
 values of the size parameters.  By default, the plot will fill this canvas.

`ratio` causes `gnuplot` to try to create a graph with an aspect ratio of <r>
 (the ratio of the y-axis length to the x-axis length) within the portion of
 the plot specified by <xscale> and <yscale>.

The meaning of a negative value for <r> is different.  If <r>=-1, gnuplot
 tries to set the scales so that the unit has the same length on both the x
 and y axes.  This is the 2D equivalent to the 3D command `set view equal xy`.
 If <r>=-2, the unit on y has twice the length of the unit on x, and so on.

The success of `gnuplot` in producing the requested aspect ratio depends on
 the terminal selected.  The graph area will be the largest rectangle of
 aspect ratio <r> that will fit into the specified portion of the output
 (leaving adequate margins, of course).

`set size square` is a synonym for `set size ratio 1`.

Both `noratio` and `nosquare` return the graph to the default aspect ratio
 of the terminal, but do not return <xscale> or <yscale> to their default
 values (1.0).

`ratio` and `square` have no effect on 3D plots, but do affect 3D projections
 created using `set view map`.  See also `set view equal`, which forces
 the x and y axes of a 3D onto the same scale.

Examples:

To set the size so that the plot fills the available canvas:
       set size 1,1

To make the graph half size and square use:
       set size square 0.5,0.5

To make the graph twice as high as wide use:
       set size ratio 2
?set spiderplot
 The `set spiderplot` command switches interpretation of coordinates to a
 polar system in which each data point is mapped to a position along a
 radial axis.  paxis 1 is always vertical; axes 2 to N proceed clockwise
 with even spacing. The command must be issued prior to plotting. It has
 additional effects equivalent to
      set style data spiderplot
      unset border
      unset tics
      set key noautotitle
      set size ratio 1.0
 Use `reset` to restore these after plotting.

?set style
?show style
?unset style
 Default plotting styles are chosen with the `set style data` and
 `set style function` commands.  See `plot with` for information about how to
 override the default plotting style for individual functions and data sets.
 See `plotting styles` or `plot with` for a complete list of styles.

Syntax:
       set style function <style>
       set style data <style>
       show style function
       show style data

Default styles for specific plotting elements may also be set.

Syntax:
       set style arrow <n> <arrowstyle>
       set style boxplot <boxplot style options>
       set style circle radius <size> {clip|noclip}
       set style ellipse size <size> units {xy|xx|yy} {clip|noclip}
       set style fill <fillstyle>
       set style histogram <histogram style options>
       set style line <n> <linestyle>
       set style rectangle <object options> <linestyle> <fillstyle>
       set style textbox {<n>} {opaque|transparent} {{no}border} {fillcolor}

?commands set style arrow
?commands unset style arrow
?commands show style arrow
?set style arrow
?unset style arrow
?show style arrow
?arrowstyle
 Each terminal has a default set of arrow and point types, which can be seen
 by using the command `test`.  `set style arrow` defines a set of arrow types
 and widths and point types and sizes so that you can refer to them later by
 an index instead of repeating all the information at each invocation.

Syntax:
       set style arrow <index> default
       set style arrow <index> {nohead | head | backhead | heads}
                               {size <length>,<angle>{,<backangle>} {fixed}}
                               {filled | empty | nofilled | noborder}
                               {front | back}
                               { {linestyle | ls <line_style>}
                                 | {linetype | lt <line_type>}
                                   {linewidth | lw <line_width}
                                   {linecolor | lc <colorspec>}
                                   {dashtype | dt <dashtype>} }
       unset style arrow
       show style arrow

<index> is an integer that identifies the arrowstyle.

If `default` is given all arrow style parameters are set to their default
 values.

If the linestyle <index> already exists, only the given parameters are
 changed while all others are preserved.  If not, all undefined values are
 set to the default values.

Specifying `nohead` produces arrows drawn without a head---a line segment.
 This gives you yet another way to draw a line segment on the plot.  By
 default, arrows have one head. Specifying `heads` draws arrow heads on both
 ends of the line.

Head size can be modified using `size <length>,<angle>` or
 `size <length>,<angle>,<backangle>`, where `<length>` defines length of each
 branch of the arrow head and `<angle>` the angle (in degrees) they make with
 the arrow.  `<Length>` is in x-axis units; this can be changed by `first`,
 `second`, `graph`, `screen`, or `character` before the <length>;  see
 `coordinates` for details.

By default the size of the arrow head is reduced for very short arrows.
 This can be disabled using the `fixed` keyword after the `size` command.

`<backangle>` is the angle (in degrees) the back branches make with the arrow
 (in the same direction as `<angle>`). It is ignored if the style is `nofilled`.

Specifying `filled` produces filled arrow heads with a border line around the
 arrow head.  Specifying `noborder` produces filled arrow heads with no border.
 In this case the tip of the arrow head lies exactly on the endpoint of the
 vector and the arrow head is slightly smaller overall. Dashed arrows should
 always use `noborder`, since a dashed border is ugly.
 Not all terminals support filled arrow heads.

The line style may be selected from a user-defined list of line styles
 (see `set style line`) or may be defined here by providing values for
 `<line_type>` (an index from the default list of styles) and/or
 `<line_width>` (which is a  multiplier for the default width).

Note, however, that if a user-defined line style has been selected, its
 properties (type and width) cannot be altered merely by issuing another
 `set style arrow` command with the appropriate index and `lt` or `lw`.

If `front` is given, the arrows are written on top of the graphed data. If
 `back` is given (the default), the arrow is written underneath the graphed
 data.  Using `front` will prevent a arrow from being obscured by dense data.

Examples:

To draw an arrow without an arrow head and double width, use:
       set style arrow 1 nohead lw 2
       set arrow arrowstyle 1

See also `set arrow` for further examples.

?commands set style boxplot
?commands unset style boxplot
?commands show style boxplot
?set style boxplot
?unset style boxplot
?show style boxplot
 The `set style boxplot` command allows you to change the layout of plots
 created using the `boxplot` plot style.

Syntax:
       set style boxplot {range <r> | fraction <f>}
                         {{no}outliers} {pointtype <p>}
                         {candlesticks | financebars}
                         {medianlinewidth <width>}
                         {separation <x>}
                         {labels off | auto | x | x2}
                         {sorted | unsorted}

The box in the boxplot always spans the range of values from the first
 quartile to the third quartile of the data points.  The limit of the whiskers
 that extend from the box can be controlled in two different ways. By default
 the whiskers extend from each end of the box for a range equal to 1.5 times
 the interquartile range (i.e. the vertical height of the box proper).
 Each whisker is truncated back toward the median so that it terminates at a
 y value belonging to some point in the data set. Since there may be no point
 whose value is exactly 1.5 times the interquartile distance, the whisker may
 be shorter than its nominal range.  This default corresponds to
       set style boxplot range 1.5

Alternatively, you can specify the fraction of the total number of points
 that the whiskers should span.  In this case the range is extended
 symmetrically from the median value until it encompasses the requested fraction
 of the data set.  Here again each whisker is constrained to end at a point in
 the data set.  To span 95% of the points in the set
       set style boxplot fraction 0.95

Any points that lie outside the range of the whiskers are considered outliers.
 By default these are drawn as individual circles (pointtype 7).  The option
 `nooutliers` disables this.
 If outliers are not drawn they do not contribute to autoscaling.

By default boxplots are drawn in a style similar to candlesticks, but you have
 the option of using instead a style similar to finance bars.

A crossbar indicating the median is drawn using the same line type as box
 boundary.  If you want a thicker line for the median
       set style boxplot medianlinewidth 2.0
 If you want no median line, set this to 0.

If the using specification for a boxplot contains a fourth column, the values
 in that column will be interpreted as the discrete leveles of a factor
 variable.  In this case more than one boxplots may be drawn, as many as the
 number of levels of the factor variable.  These boxplots will be drawn next to
 each other, the distance between them is 1.0 by default (in x-axis units).
 This distance can be changed by the option `separation`.

The `labels` option governs how and where these boxplots (each representing a
 part of the dataset) are labeled.  By default the value of the factor is put
 as a tick label on the horizontal axis -- x or x2, depending on which one is
 used for the plot itself.  This setting corresponds to option `labels auto`.
 The labels can be forced to use either of the x or x2 axes -- options
 `labels x` and `labels x2`, respectively --, or they can be turned off
 altogether with the option `labels off`.

By default the boxplots corresponding to different levels of the factor
 variable are not sorted; they will be drawn in the same order the levels are
 encountered in the data file. This behavior corresponds to the `unsorted`
 option. If the `sorted` option is active, the levels are first sorted
 alphabetically, and the boxplots are drawn in the sorted order.

The `separation`, `labels`, `sorted` and `unsorted` option only have an effect
 if a fourth column is given the plot specification.

See `boxplot`, `candlesticks`, `financebars`.

?commands set style data
?commands show style data
?set style data
?show style data
?data style
 The `set style data` command changes the default plotting style for data
 plots.

Syntax:
       set style data <plotting-style>
       show style data

See `plotting styles` for the choices.
 `show style data` shows the current default data plotting style.
?commands set style fill
?commands show style fill
?set style fill
?show style fill
?fillstyle
 The `set style fill` command is used to set the default style of the plot
 elements in plots with boxes, histograms, candlesticks and filledcurves.
 This default can be superseded by fillstyles attached to individual plots.

Note that there is a separate default fill style for rectangles created by
 `set obj`. See `set style rectangle`.

Syntax:
       set style fill {empty
                       | {transparent} solid {<density>}
                       | {transparent} pattern {<n>}}
                      {border {lt} {lc <colorspec>} | noborder}

The `empty` option causes filled areas not to be filled. This is the default.

The `solid` option causes filling with a solid color, if the terminal
 supports that. The <density> parameter specifies the intensity of the
 fill color. At a <density> of 0.0, the box is empty, at <density> of 1.0,
 the inner area is of the same color as the current linetype.
 Some terminal types can vary the density continuously; others implement
 only a few levels of partial fill.  If no <density> parameter is given,
 it defaults to 1.

The `pattern` option causes filling to be done with a fill pattern supplied
 by the terminal driver.  The kind and number of available fill patterns
 depend on the terminal driver.  If multiple datasets using filled boxes are
 plotted, the pattern cycles through all available pattern types, starting
 from pattern <n>, much as the line type cycles for multiple line plots.

?fillcolor
?fc
 Fill color (`fillcolor <colorspec>`) is distinct from fill style.  I.e.  plot
 elements or objects can share a fillstyle while retaining separate colors.
 In most places where a fillstyle is accepted you can also specify a fill color.
 Fillcolor may be abbreviated `fc`.
 Otherwise the fill color is take from the current linetype.
 Example:

plot FOO with boxes fillstyle solid 1.0 fillcolor "cyan"

?commands set style fill border
?set style fill border
?fillstyle border
 The bare keyword `border` causes the filled object to be surrounded by a
 solid line of the current linetype and color.  You can change the color of
 this line by adding either a linetype or a linecolor.
 `noborder` specifies that no bounding line is drawn.
 Examples:
      # Half-intensity fill, full intensity border in same color
      set style fill solid 0.5 border
      # Half-transparent fill, solid black border (linetype -1)
      set style fill transparent solid 0.5 border -1
      # Pattern fill in current color, border using color of linetype 5
      plot ... with boxes fillstyle pattern 2 border lt 5
      # Fill area in cyan, border in blue
      plot ... with boxes fillcolor "cyan" fs solid border linecolor "blue"

Note: The border property of a fill style only affects plots drawn
 `with filledcurves` in the default mode (closed curve).
?commands set style fill transparent
?set style fill transparent
?fillstyle transparent
?transparent
 Some terminals support the attribute `transparent` for filled areas.
 In the case of transparent solid fill areas, the `density` parameter is
 interpreted as an alpha value; that is, density 0 is fully transparent,
 density 1 is fully opaque.  In the case of transparent pattern fill, the
 background of the pattern is either fully transparent or fully opaque.

Note that there may be additional limitations on the creation or viewing of
 graphs containing transparent fill areas.  For example, the png terminal can
 only use transparent fill if the "truecolor" option is set.  Some pdf viewers
 may not correctly display the fill areas even if they are correctly described
 in the pdf file. Ghostscript/gv does not correctly display pattern-fill areas
 even though actual PostScript printers generally have no problem.
?commands set style function
?commands show style function
?set style function
?show style function
 The `set style function` command changes the default plotting style for
 function plots (e.g. lines, points, filledcurves).  See `plotting styles`.

Syntax:
       set style function <plotting-style>
       show style function
?commands set style increment
?commands show style increment
?set style increment
?show style increment
 `Note`:  This command has been deprecated.  Instead please use the newer
 command `set linetype`, which redefines the linetypes themselves rather
 than searching for a suitable temporary line style to substitute.
 See `set linetype`

Syntax:
       set style increment {default|userstyles}
       show style increment

By default, successive plots within the same graph will use successive
 linetypes from the default set for the current terminal type.
 However, choosing `set style increment user` allows you to step through
 the user-defined line styles rather than through the default linetypes.

Example:

set style line 1 lw 2 lc rgb "gold"
       set style line 2 lw 2 lc rgb "purple"
       set style line 4 lw 1 lc rgb "sea-green"
       set style increment user

plot f1(x), f2(x), f3(x), f4(x)

should plot functions f1, f2, f4 in your 3 newly defined line styles.
 If a user-defined line style is not found then the corresponding default
 linetype is used instead.  E.g. in the example above, f3(x) will be plotted
 using the default linetype 3.

?commands set style line
?commands unset style line
?commands show style line
?set style line
?unset style line
?show style line
?linestyle
?linewidth
 Each terminal has a default set of line and point types, which can be seen
 by using the command `test`.  `set style line` defines a set of line types
 and widths and point types and sizes so that you can refer to them later by
 an index instead of repeating all the information at each invocation.

Syntax:
       set style line <index> default
       set style line <index> {{linetype  | lt} <line_type> | <colorspec>}
                              {{linecolor | lc} <colorspec>}
                              {{linewidth | lw} <line_width>}
                              {{pointtype | pt} <point_type>}
                              {{pointsize | ps} <point_size>}
                              {{pointinterval | pi} <interval>}
                              {{pointnumber | pn} <max_symbols>}
                              {{dashtype | dt} <dashtype>}
                              {palette}
       unset style line
       show style line

`default` sets all line style parameters to those of the linetype with
 that same index.

If the linestyle <index> already exists, only the given parameters are
 changed while all others are preserved.  If not, all undefined values are
 set to the default values.

Line styles created by this mechanism do not replace the default linetype
 styles; both may be used.  Line styles are temporary. They are lost whenever
 you execute a `reset` command.  To redefine the linetype itself,
 please see `set linetype`.

The line and point types default to the index value. The exact symbol that is
 drawn for that index value may vary from one terminal type to another.

The line width and point size are multipliers for the current terminal's
 default width and size (but note that <point_size> here is unaffected by
 the multiplier given by the command`set pointsize`).

The `pointinterval` controls the spacing between points in a plot drawn with
 style `linespoints`.  The default is 0 (every point is drawn). For example,
 `set style line N pi 3` defines a linestyle that uses pointtype N, pointsize
 and linewidth equal to the current defaults for the terminal, and will draw
 every 3rd point in plots using `with linespoints`.  A negative value for the
 interval is treated the same as a positive value, except that some terminals
 will try to interrupt the line where it passes through the point symbol.

The `pointnumber` property is similar to `pointinterval` except that rather
 than plotting every Nth point it limits the total number of points to N.

Not all terminals support the `linewidth` and `pointsize` features; if
 not supported, the option will be ignored.

Terminal-independent colors may be assigned using either
 `linecolor <colorspec>` or `linetype <colorspec>`, abbreviated `lc` or `lt`.
 This requires giving a RGB color triple, a known palette color name,
 a fractional index into the current palette, or a constant value from the
 current mapping of the palette onto cbrange.
 See `colors`, `colorspec`, `set palette`, `colornames`, `cbrange`.

`set style line <n> linetype <lt>` will set both a terminal-dependent dot/dash
 pattern and color. The commands`set style line <n> linecolor <colorspec>` or
 `set style line <n> linetype <colorspec>` will set a new line color while
 leaving the existing dot-dash pattern unchanged.

In 3d mode (`splot` command), the special keyword `palette` is allowed as a
 shorthand for "linetype palette z".  The color value corresponds to the
 z-value (elevation) of the splot, and varies smoothly along a line or surface.

Examples:
 Suppose that the default lines for indices 1, 2, and 3 are red, green, and
 blue, respectively, and the default point shapes for the same indices are a
 square, a cross, and a triangle, respectively.  Then

set style line 1 lt 2 lw 2 pt 3 ps 0.5

defines a new linestyle that is green and twice the default width and a new
 pointstyle that is a half-sized triangle.  The commands

set style function lines
       plot f(x) lt 3, g(x) ls 1

will create a plot of f(x) using the default blue line and a plot of g(x)
 using the user-defined wide green line.  Similarly the commands

set style function linespoints
       plot p(x) lt 1 pt 3, q(x) ls 1

will create a plot of p(x) using the default triangles connected by a red
 line and q(x) using small triangles connected by a green line.

splot sin(sqrt(x*x+y*y))/sqrt(x*x+y*y) w l pal

creates a surface plot using smooth colors according to `palette`. Note,
 that this works only on some terminals. See also `set palette`, `set pm3d`.

set style line 10 linetype 1 linecolor rgb "cyan"

will assign linestyle 10 to be a solid cyan line on any terminal that
 supports rgb colors.

?commands set style circle
?commands unset style circle
?commands show style circle
?set style circle
?unset style circle
?show style circle

Syntax:
       set style circle {radius {graph|screen} <R>}
                        {{no}wedge}
                        {clip|noclip}

This command sets the default radius used in plot style "with circles".  It
 applies to data plots with only 2 columns of data (x,y) and to function plots.
 The default is "set style circle radius graph 0.02".  `Nowedge` disables
 drawing of the two radii that connect the ends of an arc to the center.
 The default is `wedge`. This parameter has no effect on full circles. `Clip`
 clips the circle at the plot boundaries, `noclip` disables this. Default is
 `clip`.

?commands set style rectangle
?commands unset style rectangle
?commands show style rectangle
?set style rectangle
?unset style rectangle
?show style rectangle

Rectangles defined with the `set object` command can have individual styles.
 However, if the object is not assigned a private style then it inherits a
 default that is taken from the `set style rectangle` command.

Syntax:
     set style rectangle {front|back} {lw|linewidth <lw>}
                         {fillcolor <colorspec>} {fs <fillstyle>}

See `colorspec` and `fillstyle`.  `fillcolor` may be abbreviated as `fc`.

Examples:
     set style rectangle back fc rgb "white" fs solid 1.0 border lt -1
     set style rectangle fc linsestyle 3 fs pattern 2 noborder

The default values correspond to solid fill with the background color and a
 black border.

?commands set style ellipse
?commands show style ellipse
?set style ellipse
?unset style ellipse
?show style ellipse

Syntax:
       set style ellipse {units xx|xy|yy}
                         {size {graph|screen} <a>, {{graph|screen} <b>}}
                         {angle <angle>}
                         {clip|noclip}

This command governs whether the diameters of ellipses are interpreted in
 the same units or not.
 Default is `xy`, which means that the major diameter (first axis) of
 ellipses will be interpreted in the same units as the x (or x2) axis,
 while the minor (second) diameter in those of the y (or y2) axis.
 In this mode the ratio of the ellipse axes depends on the scales of the
 plot axes and aspect ratio of the plot.  When set to `xx` or `yy`,
 both axes of all ellipses will be interpreted in the same units.
 This means that the ratio of the axes of the plotted ellipses will be
 correct even after rotation, but either their vertical or horizontal extent
 will not be correct.

This is a global setting that affects all ellipses, both those defined as
 objects and those generated with the `plot` command, however, the value of
 `units` can also be redefined on a per-plot and per-object basis.

It is also possible to set a default size for ellipses with the `size`
 keyword.  This default size applies to data plots with only
 2 columns of data (x,y) and to function plots.  The two values are
 interpreted as the major and minor diameters (as opposed to semi-major
 and semi-minor axes) of the ellipse.

The default is "set style ellipse size graph 0.05,0.03".

Last, but not least it is possible to set the default orientation with the
 `angle` keyword. The orientation, which is defined as the angle between the
 major axis of the ellipse and the plot's x axis, must be given in degrees.

`Clip` clips the ellipse at the plot boundaries, `noclip` disables this.
 Default is `clip`.

For defining ellipse objects, see `set object ellipse`;
 for the 2D plot style, see `ellipses`.
?commands set style parallelaxis
?set style parallelaxis
?show style parallelaxis

Syntax:
       set style parallelaxis {front|back} {line-properties}

Determines the line type and layer for drawing the vertical axes in plots
 `with parallelaxes`.  See `with parallelaxes`, `set paxis`.
?commands set style spiderplot
?set style spiderplot

Syntax:
         set style spiderplot
                   {fillstyle <fillstyle-properties>}
                   {<line-properties> | <point-properties>}
 This commands controls the default appearance of spider plots.
 The fill, line, and point properties can be modified in the first component
 of the plot command.  The overall appearance of the plot is also affected
 by other settings such as `set grid spiderplot`.  See also `set paxis`,
 `spiderplot`.
 Example:
      # Default spider plot will be a polygon with a thick border but no fill
      set style spiderplot fillstyle empty border lw 3
      # This one will additionally place an open circle (pt 6) at each axis
      plot for [i=1:6] DATA pointtype 6 pointsize 3

?commands set style textbox
?commands show style textbox
?set style textbox
?unset style textbox
?show style textbox
?textbox
?boxed

Syntax:
         set style textbox {<boxstyle-index>}
                   {opaque|transparent} {fillcolor <color>}
                   {{no}border {<bordercolor>}}{linewidth <lw>}
                   {margins <xmargin>,<ymargin>}

This command controls the appearance of labels with the attribute 'boxed'.
 Terminal types that do not support boxed text will ignore this style.
 Note: Implementation for some terminals (svg, latex) is incomplete.
 Most terminals cannot place a box correctly around rotated text.

Three numbered textbox styles can be defined.  If no boxstyle index <bs>
 is given, the default (unnumbered) style is changed.
 Example:

# default style has only a black border
      set style textbox transparent border lc "black"
      # style 2 (bs 2) has a light blue background with no border
      set style textbox 2 opaque fc "light-cyan" noborder
      set label 1 "I'm in a box" boxed
      set label 2 "I'm blue" boxed bs 2

?commands set surface
?commands unset surface
?commands show surface
?set surface
?unset surface
?show surface
?surface
?nosurface
 The `set surface` command is only relevant for 3D plots (`splot`).

Syntax:
       set surface {implicit|explicit}
       unset surface
       show surface

`unset surface` will cause `splot` to not draw points or lines corresponding
 to any of the function or data file points.  This is mainly useful for drawing
 only contour lines rather than the surface they were derived from.  Contours
 may still be drawn on the surface, depending on the `set contour` option.
 To turn off the surface for an individual function or data file while leaving
 others active, use the `nosurface` keyword in the `splot` command.
 The combination `unset surface; set contour base` is useful for displaying
 contours on the grid base.  See also `set contour`.

If a 3D data set is recognizable as a mesh (grid) then by default the program
 implicitly treats the plot style `with lines` as requesting a gridded surface.
 See `grid_data`.  The command `set surface explicit` suppresses this expansion,
 plotting only the individual lines described by separate blocks of data in the
 input file.  A gridded surface can still be plotted by explicitly requesting
 splot `with surface`.
?commands set table
?set table
?table
 When `table` mode is enabled, `plot` and `splot` commands print out a
 multicolumn text table of values
      X Y {Z} <flag>
 rather than creating an actual plot on the current terminal. The flag character
 is "i" if the point is in the active range, "o" if it is out-of-range, or "u"
 if it is undefined.  The data format is determined by the format of the axis
 tickmarks (see `set format`), and the columns are separated by single spaces.
 This can be useful if you want to generate contours and then save them for
 further use.  The same method can be used to save interpolated data
 (see `set samples` and `set dgrid3d`).

Syntax:
       set table {"outfile" | $datablock} {append}
                 {separator {whitespace|tab|comma|"<char>"}}
       plot <whatever>
       unset table

Subsequent tabular output is written to "outfile", if specified, otherwise it
 is written to stdout or other current value of `set output`.  If `outfile`
 exists it will be replaced unless the `append` keyword is given.
 Alternatively, tabular output can be redirected to a named data block.
 Data block names start with '$', see also `inline data`. You must explicitly
 `unset table` in order to go back to normal plotting on the current terminal.

The `separator` character can be used to output csv (comma separated value)
 files.  This mode only affects plot style `with table`.  See `plot with table`.

?plot with table
?with table
 This discussion applies only to the special plot style `with table`.

To avoid any style-dependent processing of the input data being tabulated
 (smoothing, errorbar expansion, secondary range checking, etc), or to increase
 the number of columns that can be tabulated, use the keyword "table" instead of
 a normal plot style.  In this case the output does not contain an extra, last,
 column of flags `i`, `o`, `u` indicated inrange/outrange/undefined.
 The destination for output must first be specified with `set table <where>`.
 For example

set table $DATABLOCK1
      plot <file> using 1:2:3:4:($5+$6):(func($7)):8:9:10 with table

Because there is no actual plot style in this case the columns do not
 correspond to specific axes.  Therefore xrange, yrange, etc are ignored.

If a `using` term evaluates to a string, the string is tabulated.
 Numerical data is always written with format %g.  If you want some other format
 use sprintf or gprintf to create a formatted string.

plot <file> using ("File 1"):1:2:3 with table
      plot <file> using (sprintf("%4.2f",$1)) : (sprintf("%4.2f",$3)) with table

To create a csv file use
      set table "tab.csv" separator comma
      plot <foo> using 1:2:3:4 with table

[EXPERIMENTAL] To select only a subset of the data points for tabulation you
 can provide an input filter condition (`if <expression>`) at the end of the
 command.  Note that the input filter may reference data columns that are not
 part of the output.  This feature may change substantially before appearing in
 a released version of gnuplot.

plot <file> using 1:2:($4+$5) with table if (strcol(3) eq "Red")
      plot <file> using 1:2:($4+$5) with table if (10. < $1 && $1 < 100.)
      plot <file> using 1:2:($4+$5) with table if (filter($6,$7) != 0)
?commands set terminal
?commands show terminal
?set terminal
?set term
?show terminal
?show term
?set terminal push
?set term push
?terminal push
?term push
?push
?set terminal pop
?set term pop
?terminal pop
?term pop
?pop
 `gnuplot` supports many different graphics devices.  Use `set terminal` to
 tell `gnuplot` what kind of output to generate. Use `set output` to redirect
 that output to a file or device.

Syntax:
       set terminal {<terminal-type> | push | pop}
       show terminal

If <terminal-type> is omitted, `gnuplot` will list the available terminal
 types.  <terminal-type> may be abbreviated.

If both `set terminal` and `set output` are used together, it is safest to
 give `set terminal` first, because some terminals set a flag which is needed
 in some operating systems.

Some terminals have many additional options.
 The options used by a previous invocation `set term <term> <options>` of a
 given `<term>` are remembered, thus subsequent `set term <term>` does
 not reset them.  This helps in printing, for instance, when switching
 among different terminals---previous options don't have to be repeated.

The command `set term push` remembers the current terminal including its
 settings while `set term pop` restores it. This is equivalent to `save term`
 and `load term`, but without accessing the filesystem. Therefore they can be
 used to achieve platform independent restoring of the terminal after printing,
 for instance. After gnuplot's startup, the default terminal or that from
 `startup` file is pushed automatically. Therefore portable scripts can rely
 that `set term pop` restores the default terminal on a given platform unless
 another terminal has been pushed explicitly.

For more information, see the `complete list of terminals`.

?commands set termoption
?set termoption
?termoption
 The `set termoption` command allows you to change the behaviour of the
 current terminal without requiring a new `set terminal` command. Only one
 option can be changed per command, and only a small number of options can
 be changed this way. Currently the only options accepted are

set termoption {no}enhanced
      set termoption font "<fontname>{,<fontsize>}"
      set termoption fontscale <scale>
      set termoption {linewidth <lw>}{lw <lw>}

?commands set theta
?set theta
?unset theta
?theta
 Polar coordinate plots are by default oriented such that theta = 0 is on the
 right side of the plot, with theta increasing as you proceed counterclockwise
 so that theta = 90 degrees is at the top.  `set theta` allows you to change
 the origin and direction of the polar angular coordinate theta.
      set theta {right|top|left|bottom}
      set theta {clockwise|cw|counterclockwise|ccw}
 `unset theta` restores the default state "set theta right ccw".
?commands set tics
?commands unset tics
?commands show tics
?set tics scale
?set tics
?unset tics
?show tics
?tics
 The `set tics` command controls the tic marks and labels on all axes at once.

The tics may be turned off with the `unset tics` command, and may be turned on
 (the default state) with `set tics`.  Fine control of tics on individual axes
 is possible using the alternative commands `set xtics`, `set ztics`, etc.

Syntax:
       set tics {axis | border} {{no}mirror}
                {in | out} {front | back}
                {{no}rotate {by <ang>}} {offset <offset> | nooffset}
                {left | right | center | autojustify}
                {format "formatstring"} {font "name{,<size>}"} {{no}enhanced}
                { textcolor <colorspec> }
       set tics scale {default | <major> {,<minor>}}
       unset tics
       show tics

The options can be applied to a single axis (x, y, z, x2, y2, cb), e.g.
       set xtics rotate by -90
       unset cbtics

All tic marks are drawn using the same line properties as the plot border
 (see `set border`).

Set tics `back` or `front` applies to all axes at once, but only for 2D plots
 (not splot).  It controls whether the tics are placed behind or in front of
 the plot elements, in the case that there is overlap.

`axis` or `border` tells `gnuplot` to put the tics (both the tics themselves
 and the accompanying labels) along the axis or the border, respectively.  If
 the axis is very close to the border, the `axis` option will move the
 tic labels to outside the border in case the border is printed (see
 `set border`).  The relevant margin settings will usually be sized badly by
 the automatic layout algorithm in this case.

`mirror` tells `gnuplot` to put unlabeled tics at the same positions on the
 opposite border.  `nomirror` does what you think it does.

`in` and `out` change the tic marks to be drawn inwards or outwards.

`set tics scale` controls the size of the tic marks.  The first value <major>
 controls the auto-generated or user-specified major tics (level 0).  The
 second value controls the auto-generated or user-specified minor tics
 (level 1).  <major> defaults to 1.0, <minor> defaults to <major>/2.
 Additional values control the size of user-specified tics with level 2, 3, ...
 Default tic sizes are restored by `set tics scale default`.

`rotate` asks `gnuplot` to rotate the text through 90 degrees, which will be
 done if the terminal driver in use supports text rotation.  `norotate`
 cancels this. `rotate by <ang>` asks for rotation by <ang> degrees, supported
 by some terminal types.

The defaults are `border mirror norotate` for tics on the x and y axes, and
 `border nomirror norotate` for tics on the x2 and y2 axes.  For the z axis,
 the default is `nomirror`.

The <offset> is specified by either x,y or x,y,z, and may be preceded by
 `first`, `second`, `graph`, `screen`, or `character` to select the
 coordinate system. <offset> is the offset of the tics texts from their
 default positions, while the default coordinate system is `character`.
 See `coordinates` for details. `nooffset` switches off the offset.

By default, tic labels are justified automatically depending on the axis and
 rotation angle to produce aesthetically pleasing results. If this is not
 desired, justification can be overridden with an explicit `left`, `right` or
 `center` keyword. `autojustify` restores the default behavior.

`set tics` with no options restores mirrored, inward-facing tic marks for
 the primary axes. All other settings are retained.

See also `set xtics` for more control of major (labeled) tic marks and
 `set mxtics` for control of minor tic marks.  These commands provide control
 of each axis independently.
?commands set ticslevel
?commands show ticslevel
?set ticslevel
?show ticslevel
?ticslevel
 Deprecated. See `set xyplane`.
?commands set ticscale
?commands show ticscale
?set ticscale
?show ticscale
?ticscale
 The `set ticscale` command is deprecated, use `set tics scale` instead.
?commands set timestamp
?commands unset timestamp
?commands show timestamp
?set timestamp
?unset timestamp
?show timestamp
?timestamp
?notimestamp
 The command `set timestamp` places the current time and date in the plot margin.

Syntax:
       set timestamp {"<format>"} {top|bottom} {{no}rotate}
                     {offset <xoff>{,<yoff>}} {font "<fontspec>"}
                     {textcolor <colorspec>}
       unset timestamp
       show timestamp

The format string is used to write the date and time.  Its default value is
 what asctime() uses: "%a %b %d %H:%M:%S %Y" (weekday, month name, day of the
 month, hours, minutes, seconds, four-digit year).  With `top` or `bottom` you
 can place the timestamp along the top left or bottom left margin
 (default: bottom).  `rotate` writes the timestamp vertically. The constants
 <xoff> and <yoff> are offsets that let you adjust the position more finely.
 <font> is used to specify the font with which the time is to be written.

The abbreviation `time` may be used in place of `timestamp`.

Example:
       set timestamp "%d/%m/%y %H:%M" offset 80,-2 font "Helvetica"

See `set timefmt` for more information about time format strings.
?commands set timefmt
?commands show timefmt
?set timefmt
?show timefmt
?timefmt
 This command sets the default format used to input time data.
 See `set xdata time`, `timecolumn`.

Syntax:
       set timefmt "<format string>"
       show timefmt

The valid formats for both `timefmt` and `timecolumn` are:

Format       Explanation
       %d           day of the month, 1--31
       %m           month of the year, 1--12
       %y           year, 0--99
       %Y           year, 4-digit
       %j           day of the year, 1--365
       %H           hour, 0--24
       %M           minute, 0--60
       %s           seconds since the Unix epoch (1970-01-01, 00:00 UTC)
       %S           second, integer 0--60 on output, (double) on input
       %b           three-character abbreviation of the name of the month
       %B           name of the month
       %p           two character match to one of:  am AM pm PM

Any character is allowed in the string, but must match exactly.  \t (tab) is
 recognized.  Backslash-octals (\nnn) are converted to char.  If there is no
 separating character between the time/date elements, then %d, %m, %y, %H, %M
 and %S read two digits each.  If a decimal point immediately follows the field
 read by %S, the decimal and any following digits are interpreted as a
 fractional second.  %Y reads four digits. %j reads three digits.
 %b requires three characters, and %B requires as many as it needs.

Spaces are treated slightly differently.  A space in the string stands for
 zero or more whitespace characters in the file.  That is, "%H %M" can be used
 to read "1220" and "12     20" as well as "12 20".

Each set of non-blank characters in the timedata counts as one column in the
 `using n:n` specification.  Thus `11:11  25/12/76  21.0` consists of three
 columns.  To avoid confusion, `gnuplot` requires that you provide a complete
 `using` specification if your file contains timedata.

If the date format includes the day or month in words, the format string must
 exclude this text.  But it can still be printed with the "%a", "%A", "%b", or
 "%B" specifier.  `gnuplot` will determine the proper month and weekday from the
 numerical values.  See `set format` for more details about these and other
 options for printing time data.

When reading two-digit years with %y, values 69-99 refer to the 20th century,
 while values 00-68 refer to the 21st century.   NB: This is in accordance with
 the UNIX98 spec, but conventions vary widely and two-digit year values are
 inherently ambiguous.

If the %p format returns "am" or "AM", hour 12 will be interpreted as hour 0.
 If the %p format returns "pm" or "PM", hours < 12 will be increased by 12.

See also `set xdata` and `time/date` for more information.

Example:
       set timefmt "%d/%m/%Y\t%H:%M"
 tells `gnuplot` to read date and time separated by tab.  (But look closely at
 your data---what began as a tab may have been converted to spaces somewhere
 along the line; the format string must match what is actually in the file.)
 See also
 time data demo.
?commands set title
?commands show title
?set title
?show title
?title
 The `set title` command produces a plot title that is centered at the top of
 the plot.  `set title` is a special case of `set label`.

Syntax:
       set title {"<title-text>"} {offset <offset>} {font "<font>{,<size>}"}
                 {{textcolor | tc} {<colorspec> | default}} {{no}enhanced}
       show title

If <offset> is specified by either x,y or x,y,z the title is moved by the
 given offset.  It may be preceded by `first`, `second`, `graph`, `screen`,
 or `character` to select the coordinate system.  See `coordinates` for
 details.  By default, the `character` coordinate system is used.  For
 example, "`set title offset 0,-1`" will change only the y offset of the
 title, moving the title down by roughly the height of one character.  The
 size of a character depends on both the font and the terminal.

<font> is used to specify the font with which the title is to be written;
 the units of the font <size> depend upon which terminal is used.

`textcolor <colorspec>` changes the color of the text. <colorspec> can be a
 linetype, an rgb color, or a palette mapping. See help for `colorspec` and
 `palette`.

`noenhanced` requests that the title not be processed by the enhanced text
 mode parser, even if enhanced text mode is currently active.

`set title` with no parameters clears the title.

See `syntax` for details about the processing of backslash sequences and
 the distinction between single- and double-quotes.
?commands set tmargin
?set tmargin
?tmargin
 The command `set tmargin` sets the size of the top margin.
 Please see `set margin` for details.
?commands set trange
?commands show trange
?set trange
?show trange
?trange
 Syntax:    set trange [tmin:tmax]
 The range of the parametric variable t is useful in three contexts.
 1) In parametric mode `plot` commands it limits the range of sampling
    for both generating functions.  See `set parametric`, `set samples`.
 2) In polar mode `plot` commands it limits or defines the range of the
    angular parameter theta. See `polar`.
 3) In `plot` or `splot` commands using 1-dimensional sampled data via
    the pseudofile "+".  See `sampling 1D`, `special-filenames`.
?commands set ttics
?commands show ttics
?set ttics
?show ttics
?ttics
 The `set ttics` command places tics around the perimeter of a polar plot.
 This is the border if `set border polar` is enabled, otherwise the outermost
 circle of the polar grid drawn at the rightmost ticmark along the r axis.
 See `set grid`, `set rtics`. The angular position is always labeled in degrees.
 The full perimeter can be labeled regardless of the current trange setting.
 The desired range of the tic labels should be given as shown below.
 Additional properties of the tic marks can be set. See `xtics`.

set ttics -180, 30, 180
      set ttics add ("Theta = 0" 0)
      set ttics font ":Italic" rotate
?commands set urange
?commands show urange
?set urange
?show urange
?urange
 Syntax:     set urange [umin:umax]
 The range of the parametric variables u and v is useful in two contexts.
 1) `splot` in parametric mode. See `set parametric`, `set isosamples`.
 2) generating 2-dimension sampled data for either `plot` or `splot` using the
 pseudofile "++". See `sampling 2D`.
?commands show variables
?show variables all
?show variables
 The `show variables` command lists the current value of user-defined and
 internal variables. Gnuplot internally defines variables whose names begin
 with GPVAL_, MOUSE_, FIT_, and TERM_.

Syntax:
       show variables      # show variables that do not begin with GPVAL_
       show variables all  # show all variables including those beginning GPVAL_
       show variables NAME # show only variables beginning with NAME

?show version
 The `show version` command lists the version of gnuplot being run, its last
 modification date, the copyright holders, and email addresses for the FAQ,
 the gnuplot-info mailing list, and reporting bugs--in short, the information
 listed on the screen when the program is invoked interactively.

Syntax:
       show version {long}

When the `long` option is given, it also lists the operating system, the
 compilation options used when `gnuplot` was installed, the location of the
 help file, and (again) the useful email addresses.
?commands set vgrid
?set vgrid
?unset vgrid
?show vgrid
?vgrid
 Syntax:
      set vgrid $gridname {size N}
      unset vgrid $gridname
      show vgrid

If the named grid already exists, mark it as active (use it for subsequent
 `vfill` and `voxel` operations).  If a new size is given, replace the existing
 content with a zero-filled N x N x N grid.  If a grid with this name does not
 already exist, allocate an N x N x N grid (default N=100), zero the contents,
 and mark it as active.  Note that grid names must begin with '$'.

`show vgrid` lists all currently defined voxel grids.
 Example output:
       $vgrid1: (active)
                size 100 X 100 X 100
                vxrange [-4:4]  vyrange[-4:4]  vzrange[-4:4]
                non-zero voxel values:  min 0.061237 max 94.5604
                number of zero voxels:  992070   (99.21%)

`unset vgrid $gridname` releases all data structures associated with that
 voxel grid.  The data structures are also released by `reset session`.
 The function `voxel(x,y,z)` returns the value of the active grid point
 nearest that coordinate. See also `splot voxel-grids`.

?commands set view
?commands show view
?set view
?set view map
?show view
?view
 The `set view` command sets the viewing angle for `splot`s.  It controls how
 the 3D coordinates of the plot are mapped into the 2D screen space.  It
 provides controls for both rotation and scaling of the plotted data, but
 supports orthographic projections only.  It supports both 3D projection or
 orthogonal 2D projection into a 2D plot-like map.

Syntax:
       set view <rot_x>{,{<rot_z>}{,{<scale>}{,<scale_z>}}}
       set view map {scale <scale>}
       set view projection {xy|xz|yz}
       set view {no}equal {xy|xyz}
       set view azimuth <angle>
       show view

where <rot_x> and <rot_z> control the rotation angles (in degrees) in a
 virtual 3D coordinate system aligned with the screen such that initially
 (that is, before the rotations are performed) the screen horizontal axis is
 x, screen vertical axis is y, and the axis perpendicular to the screen is z.
 The first rotation applied is <rot_x> around the x axis.  The second rotation
 applied is <rot_z> around the new z axis.

Command `set view map` is used to represent the drawing as a map. It is useful
 for `contour` plots or 2D heatmaps using pm3d mode rather than `with image`.
 In the latter case, take care that you properly use `zrange` and `cbrange` for
 input data point filtering and color range scaling, respectively.

<rot_x> is bounded to the [0:180] range with a default of 60 degrees, while
 <rot_z> is bounded to the [0:360] range with a default of 30 degrees.
 <scale> controls the scaling of the entire `splot`, while <scale_z> scales
 the z axis only.  Both scales default to 1.0.

Examples:
       set view 60, 30, 1, 1
       set view ,,0.5

The first sets all the four default values.  The second changes only scale,
 to 0.5.
?set view azimuth
?view azimuth
?azimuth
       set view azimuth <angle-in-degrees>
 The setting of azimuth affects the orientation of the z axis in a 3D graph
 (splot). At the default azimuth = 0 the z axis of the plot lies in the plane
 orthogonal to the screen horizontal.  I.e. the projection of the z axis lies
 along the screen vertical.  Non-zero azimuth rotates the plot about the line
 of sight through the origin so that a projection of the z axis is no longer
 vertical.  When azimuth = 90 the z axis is horizontal rather than vertical.
?set view equal_axes
?set view equal xyz
?set view equal
?view equal_axes
?view equal xyz
?equal_axes
?equal xyz
 The command `set view equal xy` forces the unit length of the x and y axes
 to be on the same scale, and chooses that scale so that the plot will fit on
 the page.  The command `set view equal xyz` additionally sets the z axis
 scale to match the x and y axes; however there is no guarantee that the
 current z axis range will fit within the plot boundary.
 By default all three axes are scaled independently to fill the available area.

See also `set xyplane`.
?set view projection
?view projection
?projection
 Syntax:
      set view projection {xy|xz|yz}
 Rotates the view angles of a 3D plot so that one of the primary planes
 xy, xz, or yz lies in the plane of the plot.  Axis labels and tics positioning
 is adjusted accordingly;  tics and labels on the third axis are disabled.
 The plot is scaled up to approximately match the size that 'plot' would
 generate for the same axis ranges.
 `set view projection xy` is equivalent to `set view map`.
?commands set vrange
?commands show vrange
?set vrange
?show vrange
?vrange
 Syntax:     set vrange [vmin:vmax]
 The range of the parametric variables u and v is useful in two contexts.
 1) `splot` in parametric mode. See `set parametric`, `set isosamples`.
 2) generating 2-dimension sampled data for either `plot` or `splot` using the
 pseudofile "++". See `sampling 2D`.
?commands set vxrange
?set vxrange
?vxrange
 Syntax:      set vxrange [vxmin:vxmax]

Establishes the range of x coordinates spanned by the active voxel grid.
 Analogous commands `set vyrange` and `set vzrange` exist for the other two
 dimensions of the voxel grid.  If no explicit ranges have been set prior to
 the first `vclear`, `vfill`, or `voxel(x,y,z) = ` command, vmin and vmax
 will be copied from the current values of `xrange`.
?commands set vyrange
?set vyrange
?vyrange
 See `set vxrange`
?commands set vzrange
?set vzrange
?vzrange
 See `set vxrange`
?commands set walls
?commands show walls
?set walls
?show walls
?unset walls
?walls
 Syntax:
      set walls
      set wall {x0|y0|z0|x1|y1} {<fillstyle>} {fc <fillcolor>}

3D surfaces drawn by `splot` lie within a normalized unit cube regardless
 of the x y and z axis ranges. The bounding walls of this cube are described by
 the planes (graph coord x == 0), (graph coord x == 1), etc.  The `set walls`
 command renders the walls x0 y0 and z0 as solid surfaces.  By default these
 surfaces are semi-transparent (fillstyle transparent solid 0.5).  You can
 customize which walls are drawn and also their individual color and fill style.
 If you choose to enable walls, you may also want to use `set xyplane 0`.
 Example:

set wall z0 fillstyle solid 1.0 fillcolor "gray"
?commands set x2data
?commands show x2data
?set x2data
?show x2data
?x2data
 The `set x2data` command sets data on the x2 (top) axis to timeseries
 (dates/times).  Please see `set xdata`.
?commands set x2dtics
?commands unset x2dtics
?commands show x2dtics
?set x2dtics
?unset x2dtics
?show x2dtics
?x2dtics
?nox2dtics
 The `set x2dtics` command changes tics on the x2 (top) axis to days of the
 week.  Please see `set xdtics` for details.
?commands set x2label
?commands show x2label
?set x2label
?show x2label
?x2label
 The `set x2label` command sets the label for the x2 (top) axis.
 Please see `set xlabel`.
?commands set x2mtics
?commands unset x2mtics
?commands show x2mtics
?set x2mtics
?unset x2mtics
?show x2mtics
?x2mtics
?nox2mtics
 The `set x2mtics` command changes tics on the x2 (top) axis to months of the
 year.  Please see `set xmtics` for details.
?commands set x2range
?commands show x2range
?set x2range
?show x2range
?x2range
 The `set x2range` command sets the horizontal range that will be displayed on
 the x2 (top) axis.  See `set xrange` for the full set of command options.
 See also `set link`.
?commands set x2tics
?commands unset x2tics
?commands show x2tics
?set x2tics
?unset x2tics
?show x2tics
?x2tics
?nox2tics
 The `set x2tics` command controls major (labeled) tics on the x2 (top) axis.
 Please see `set xtics` for details.
?commands set x2zeroaxis
?commands unset x2zeroaxis
?commands show x2zeroaxis
?set x2zeroaxis
?unset x2zeroaxis
?show x2zeroaxis
?x2zeroaxis
?nox2zeroaxis
 The `set x2zeroaxis` command draws a line at the origin of the x2 (top) axis
 (y2 = 0).  For details, please see `set zeroaxis`.
?commands set xdata
?commands show xdata
?set xdata
?show xdata
?xdata
 This command controls interpretation of data on the x axis.
 An analogous command acts on each of the other axes.

Syntax:
       set xdata time
       show xdata

The same syntax applies to `ydata`, `zdata`, `x2data`, `y2data` and `cbdata`.

The `time` option signals that data represents a time/date in seconds.
 The current version of gnuplot stores time to a millisecond precision.

If no option is specified, the data interpretation reverts to normal.
?commands set xdata time
?set xdata time
 `set xdata time` indicates that the x coordinate represents a date or time to
 millisecond precision.  There is an analogous command `set ydata time`.

There are separate format mechanisms for interpretation of time data on input
 and output.  Input data is read from a file either by using the global
 `timefmt` or by using the function timecolumn() as part of the plot command.
 These input mechanisms also apply to using time values to set an axis range.
 See `set timefmt`, `timecolumn`.

Example:

set xdata time
      set timefmt "%d-%b-%Y"
      set xrange ["01-Jan-2013" : "31-Dec-2014"]
      plot DATA using 1:2
 or
      plot DATA using (timecolumn(1,"%d-%b-%Y")):2

For output, i.e. tick labels along that axis or coordinates output by mousing,
 the function 'strftime' (type "man strftime" on unix to look it up) is used to
 convert from the internal time in seconds to a string representation of a date.
 `gnuplot` tries to figure out a reasonable format for this.  You can customize
 the format using either `set format x` or `set xtics format`.
 See `time_specifiers` for a special set of time format specifiers.
 See also `time/date` for more information.
?commands set xdtics
?commands unset xdtics
?commands show xdtics
?set xdtics
?unset xdtics
?show xdtics
?xdtics
?noxdtics
 The `set xdtics` commands converts the x-axis tic marks to days of the week
 where 0=Sun and 6=Sat.  Overflows are converted modulo 7 to dates.  `set
 noxdtics` returns the labels to their default values.  Similar commands do
 the same things for the other axes.

Syntax:
       set xdtics
       unset xdtics
       show xdtics

The same syntax applies to `ydtics`, `zdtics`, `x2dtics`, `y2dtics` and
 `cbdtics`.

See also the `set format` command.
?commands set xlabel
?commands show xlabel
?set xlabel
?show xlabel
?xlabel
 The `set xlabel` command sets the x axis label.  Similar commands set labels
 on the other axes.

Syntax:
       set xlabel {"<label>"} {offset <offset>} {font "<font>{,<size>}"}
                  {textcolor <colorspec>} {{no}enhanced}
                  {rotate by <degrees> | rotate parallel | norotate}
       show xlabel

The same syntax applies to `x2label`, `ylabel`, `y2label`, `zlabel` and
 `cblabel`.

If <offset> is specified by either x,y or x,y,z the label is moved by the
 given offset.  It may be preceded by `first`, `second`, `graph`, `screen`,
 or `character` to select the coordinate system.  See `coordinates` for
 details.  By default, the `character` coordinate system is used.  For
 example, "`set xlabel offset -1,0`" will change only the x offset of the
 title, moving the label roughly one character width to the left.  The size
 of a character depends on both the font and the terminal.

<font> is used to specify the font in which the label is written; the units
 of the font <size> depend upon which terminal is used.

`noenhanced` requests that the label text not be processed by the enhanced text
 mode parser, even if enhanced text mode is currently active.

To clear a label, put no options on the command line, e.g., "`set y2label`".

The default positions of the axis labels are as follows:

xlabel:  The x-axis label is centered below the bottom of the plot.

ylabel:  The y-axis label is centered to the left of the plot, defaulting to
 either horizontal or vertical orientation depending on the terminal type.
 The program may not reserve enough space to the left of the plot to hold long
 non-rotated ylabel text.  You can adjust this with `set lmargin`.

zlabel: The z-axis label is centered along the z axis and placed in the space
 above the grid level.

cblabel: The color box axis label is centered along the box and placed below
 or to the right according to horizontal or vertical color box gradient.

y2label: The y2-axis label is placed to the right of the y2 axis.  The
 position is terminal-dependent in the same manner as is the y-axis label.

x2label: The x2-axis label is placed above the plot but below the title.
 It is also possible to create an x2-axis label by using new-line
 characters to make a multi-line plot title, e.g.,

set title "This is the title\n\nThis is the x2label"

Note that double quotes must be used.  The same font will be used for both
 lines, of course.

The orientation (rotation angle) of the x, x2, y and y2 axis labels in 2D plots
 can be changed by specifying `rotate by <degrees>`.  The orientation of the x
 and y axis labels in 3D plots defaults to horizontal but can be changed to run
 parallel to the axis by specifying `rotate parallel`.

If you are not satisfied with the default position of an axis label, use `set
 label` instead--that command gives you much more control over where text is
 placed.

Please see `syntax` for further information about backslash processing
 and the difference between single- and double-quoted strings.
?commands set xmtics
?commands unset xmtics
?commands show xmtics
?set xmtics
?unset xmtics
?show xmtics
?xmtics
?noxmtics
 The `set xmtics` command converts the x-axis tic marks to months of the
 year where 1=Jan and 12=Dec.  Overflows are converted modulo 12 to months.
 The tics are returned to their default labels by `unset xmtics`.  Similar
 commands perform the same duties for the other axes.

Syntax:
       set xmtics
       unset xmtics
       show xmtics

The same syntax applies to `x2mtics`, `ymtics`, `y2mtics`, `zmtics` and
 `cbmtics`.

See also the `set format` command.
?commands set xrange
?commands show xrange
?set xrange
?show xrange
?set range
?writeback
?restore
?xrange
 The `set xrange` command sets the horizontal range that will be displayed.
 A similar command exists for each of the other axes, as well as for the
 polar radius r and the parametric variables t, u, and v.

Syntax:
       set xrange [{{<min>}:{<max>}}] {{no}reverse} {{no}writeback} {{no}extend}
                  | restore
       show xrange

where <min> and <max> terms are constants, expressions or an asterisk to set
 autoscaling.  If the data are time/date, you must give the range as a quoted
 string according to the `set timefmt` format.
 If <min> or <max> is omitted the current value will not be changed.
 See below for full autoscaling syntax.  See also `noextend`.

The same syntax applies to `yrange`, `zrange`, `x2range`, `y2range`, `cbrange`,
 `rrange`, `trange`, `urange` and `vrange`.

See `set link` for options that link the ranges of x and x2, or y and y2.

The `reverse` option reverses the direction of an autoscaled axis. For example,
 if the data values range from 10 to 100, it will autoscale to the equivalent of
 set xrange [100:10].  The `reverse` flag has no effect if the axis is not
 autoscaled. NB: This is a change introduced in version 4.7.

Autoscaling:  If <min> (the same applies for correspondingly to <max>) is
 an asterisk "*" autoscaling is turned on.  The range in which autoscaling
 is being performed may be limited by a lower bound <lb> or an upper bound
 <ub> or both.  The syntax is
       { <lb> < } * { < <ub> }
 For example,
       0 < * < 200
 sets <lb> = 0 and <ub> = 200.  With such a setting <min> would be autoscaled,
 but its final value will be between 0 and 200 (both inclusive despite the
 '<' sign).  If no lower or upper bound is specified, the '<' to also be
 omitted.  If <ub> is lower than <lb> the constraints will be turned off
 and full autoscaling will happen.
 This feature is useful to plot measured data with autoscaling but providing
 a limit on the range, to clip outliers, or to guarantee a minimum range
 that will be displayed even if the data would not need such a big range.

The `writeback` option essentially saves the range found by `autoscale` in
 the buffers that would be filled by `set xrange`.  This is useful if you wish
 to plot several functions together but have the range determined by only
 some of them.  The `writeback` operation is performed during the `plot`
 execution, so it must be specified before that command.  To restore,
 the last saved horizontal range use `set xrange restore`.  For example,

set xrange [-10:10]
       set yrange [] writeback
       plot sin(x)
       set yrange restore
       replot x/2

results in a yrange of [-1:1] as found only from the range of sin(x); the
 [-5:5] range of x/2 is ignored.  Executing `show yrange` after each command
 in the above example should help you understand what is going on.

In 2D, `xrange` and `yrange` determine the extent of the axes, `trange`
 determines the range of the parametric variable in parametric mode or the
 range of the angle in polar mode.  Similarly in parametric 3D, `xrange`,
 `yrange`, and `zrange` govern the axes and `urange` and `vrange` govern the
 parametric variables.

In polar mode, `rrange` determines the radial range plotted.  <rmin> acts as
 an additive constant to the radius, whereas <rmax> acts as a clip to the
 radius---no point with radius greater than <rmax> will be plotted.  `xrange`
 and `yrange` are affected---the ranges can be set as if the graph was of
 r(t)-rmin, with rmin added to all the labels.

Any range may be partially or totally autoscaled, although it may not make
 sense to autoscale a parametric variable unless it is plotted with data.

Ranges may also be specified on the `plot` command line.  A range given on
 the plot line will be used for that single `plot` command; a range given by
 a `set` command will be used for all subsequent plots that do not specify
 their own ranges.  The same holds true for `splot`.
?commands set xrange examples
?set xrange examples
?set range examples
?xrange examples
 Examples:

To set the xrange to the default:
       set xrange [-10:10]

To set the yrange to increase downwards:
       set yrange [10:-10]

To change zmax to 10 without affecting zmin (which may still be autoscaled):
       set zrange [:10]

To autoscale xmin while leaving xmax unchanged:
       set xrange [*:]

To autoscale xmin but keeping xmin positive:
       set xrange [0<*:]

To autoscale x but keep minimum range of 10 to 50 (actual might be larger):
       set xrange [*<10:50<*]

Autoscaling but limit maximum xrange to -1000 to 1000, i.e. autoscaling
 within [-1000:1000]
       set xrange [-1000<*:*<1000]

Make sure xmin is somewhere between -200 and 100:
       set xrange [-200<*<100:]
?commands set xrange noextend
?set xrange noextend
?set range noextend
?xrange noextend
?set xrange extend
?set range extend
?xrange extend
 `set xrange noextend` is the same as `set autoscale x noextend`.
 See `noextend`.
?commands set xtics
?commands unset xtics
?commands show xtics
?set xtics
?unset xtics
?show xtics
?xtics
?noxtics
 Fine control of the major (labeled) tics on the x axis is possible with the
 `set xtics` command.  The tics may be turned off with the `unset xtics`
 command, and may be turned on (the default state) with `set xtics`.  Similar
 commands control the major tics on the y, z, x2 and y2 axes.

Syntax:
       set xtics {axis | border} {{no}mirror}
                 {in | out} {scale {default | <major> {,<minor>}}}
                 {{no}rotate {by <ang>}} {offset <offset> | nooffset}
                 {left | right | center | autojustify}
                 {add}
                 {  autofreq
                  | <incr>
                  | <start>, <incr> {,<end>}
                  | ({"<label>"} <pos> {<level>} {,{"<label>"}...) }
                 {format "formatstring"} {font "name{,<size>}"} {{no}enhanced}
                 { numeric | timedate | geographic }
                 {{no}logscale}
                 { rangelimited }
                 { textcolor <colorspec> }
       unset xtics
       show xtics

The same syntax applies to `ytics`, `ztics`, `x2tics`, `y2tics` and `cbtics`.

`axis` or `border` tells `gnuplot` to put the tics (both the tics themselves
 and the accompanying labels) along the axis or the border, respectively.  If
 the axis is very close to the border, the `axis` option will move the
 tic labels to outside the border.  The relevant margin settings will usually
 be sized badly by the automatic layout algorithm in this case.

`mirror` tells `gnuplot` to put unlabeled tics at the same positions on the
 opposite border.  `nomirror` does what you think it does.

`in` and `out` change the tic marks to be drawn inwards or outwards.

With `scale`, the size of the tic marks can be adjusted. If <minor> is not
 specified, it is 0.5*<major>.  The default size 1.0 for major tics and 0.5
 for minor tics is requested by `scale default`.

The defaults are `border mirror norotate` for tics on the x and y axes, and
 `border nomirror norotate` for tics on the x2 and y2 axes.  For the z axis,
 the `{axis | border}` option is not available and the default is
 `nomirror`.  If you do want to mirror the z-axis tics, you might want to
 create a bit more room for them with `set border`.

Example:

Move xtics more closely to the plot.
       set xtics offset 0,graph 0.05

`set xtics` with no options restores the default border or axis if xtics are
 being displayed;  otherwise it has no effect.  Any previously specified tic
 frequency or position {and labels} are retained.

Tic positions are calculated automatically by default or if the `autofreq`
 option is given.

A series of tic positions can be specified by giving either a tic interval
 alone, or a start point, interval, and end point (see `xtics series`).

Individual tic positions can be specified individually by providing an
 explicit list of positions, where each position may have an associated
 text label. See `xtics list`.

However they are specified, tics will only be plotted when in range.

Format (or omission) of the tic labels is controlled by `set format`, unless
 the explicit text of a label is included in the `set xtics ("<label>")` form.

Minor (unlabeled) tics can be added automatically by the `set mxtics`
 command, or at explicit positions by the `set xtics ("" <pos> 1, ...)` form.

The appearance of the tics (line style, line width etc.) is determined by the
 border line (see `set border`), even if the tics are drawn at the axes.
?set xtics series
?xtics series
 Syntax:
      set xtics <incr>
      set xtics <start>, <incr>, <end>
 The implicit <start>, <incr>, <end> form specifies that a series of tics will
 be plotted on the axis between the values <start> and <end> with an increment
 of <incr>.  If <end> is not given, it is assumed to be infinity.  The
 increment may be negative.  If neither <start> nor <end> is given, <start> is
 assumed to be negative infinity, <end> is assumed to be positive infinity,
 and the tics will be drawn at integral multiples of <incr>.  If the axis is
 logarithmic, the increment will be used as a multiplicative factor.

If you specify to a negative <start> or <incr> after a numerical value
 (e.g., `rotate by <angle>` or `offset <offset>`), the parser fails because
 it subtracts <start> or <incr> from that value.  As a workaround, specify
 `0-<start>` resp. `0-<incr>` in that case.

Example:
       set xtics border offset 0,0.5 -5,1,5
 Fails with 'invalid expression' at the last comma.
       set xtics border offset 0,0.5 0-5,1,5
 or
       set xtics offset 0,0.5 border -5,1,5
 Sets tics at the border, tics text with an offset of 0,0.5 characters, and
 sets the start, increment, and end to -5, 1, and 5, as requested.

The `set grid` options 'front', 'back' and 'layerdefault' affect the drawing
 order of the xtics, too.

Examples:

Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
       set xtics 0,.5,10

Make tics at ..., -10, -5, 0, 5, 10, ...
       set xtics 5

Make tics at 1, 100, 1e4, 1e6, 1e8.
       set logscale x; set xtics 1,100,1e8

?set xtics list
?set xtics add
?xtics list
?xtics add
 Syntax:
      set xtics {add} ("label1" <pos1> <level1>, "label2" <pos2> <level2>, ...)

The explicit ("label" <pos> <level>, ...) form allows arbitrary tic
 positions or non-numeric tic labels.  In this form, the tics do not
 need to be listed in numerical order.  Each tic has a
 position, optionally with a label.

The label is a string enclosed by quotes or a string-valued expression.
 It may contain formatting information for converting the position into its
 label, such as "%3f clients", or it may be the empty string "".
 See `set format` for more information.  If no string is given, the
 default label (numerical) is used.

An explicit tic mark has a third parameter, the level.
 The default is level 0, a major tic.  Level 1 generates a minor tic.
 Labels are never printed for minor tics.  Major and minor tics may be
 auto-generated by the program or specified explicitly by the user.
 Tics with level 2 and higher must be explicitly specified by the user, and
 take priority over auto-generated tics.  The size of tics marks at each
 level is controlled by the command `set tics scale`.

Examples:
       set xtics ("low" 0, "medium" 50, "high" 100)
       set xtics (1,2,4,8,16,32,64,128,256,512,1024)
       set ytics ("bottom" 0, "" 10, "top" 20)
       set ytics ("bottom" 0, "" 10 1, "top" 20)

In the second example, all tics are labeled.  In the third, only the end
 tics are labeled.  In the fourth, the unlabeled tic is a minor tic.

Normally if explicit tics are given, they are used instead of auto-generated
 tics. Conversely if you specify `set xtics auto` or the like it will erase
 any previously specified explicit tics. You can mix explicit and auto-
 generated tics by using the keyword `add`, which must appear before
 the tic style being added.

Example:
       set xtics 0,.5,10
       set xtics add ("Pi" 3.14159)

This will automatically generate tic marks every 0.5 along x, but will
 also add an explicit labeled tic mark at pi.
?set xtics timedata
?xtics timedata tics
?set xtics time
?xtics time
?timedata tics
 Times and dates are stored internally as a number of seconds.

Input: Non-numeric time and date values are converted to seconds on input using
 the format specifier in `timefmt`.  Axis positions and range limits also may be
 given as quoted dates or times interpreted using `timefmt`.
 If the <start>, <incr>, <end> form is used, <incr> must be in seconds.
 Use of `timefmt` to interpret input data, range, and tic positions is triggered
 by `set xdata time`.

Output: Axis tic labels are generated using a separate format specified either
 by `set format` or `set xtics format`.  By default the usual numeric format
 specifiers are expected (`set xtics numeric`).  Other options are geographic
 coordinates (`set xtics geographic`), or times or dates (`set xtics time`).

Note: For backward compatibility with earlier gnuplot versions, the command
 `set xdata time` will implicitly also do `set xtics time`, and `set xdata`
 or `unset xdata` will implicitly reset to `set xtics numeric`.  However you
 can change this with a later call to `set xtics`.

Examples:
       set xdata time           # controls interpretation of input data
       set timefmt "%d/%m"      # format used to read input data
       set xtics timedate       # controls interpretation of output format
       set xtics format "%b %d" # format used for tic labels
       set xrange ["01/12":"06/12"]
       set xtics "01/12", 172800, "05/12"

set xdata time
       set timefmt "%d/%m"
       set xtics format "%b %d" time
       set xrange ["01/12":"06/12"]
       set xtics ("01/12", "" "03/12", "05/12")
 Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5", but in the
 second example the tic at "Dec 3" will be unlabeled.
?commands set xtics geographic
?set xtics geographic
?geographic
 `set xtics geographic` indicates that x-axis values are to be interpreted as
 a geographic coordinate measured in degrees.  Use `set xtics format` or
 `set format x` to specify the appearance of the axis tick labels.
 The format specifiers for geographic data are as follows:
        %D                   = integer degrees
        %<width.precision>d  = floating point degrees
        %M                   = integer minutes
        %<width.precision>m  = floating point minutes
        %S                   = integer seconds
        %<width.precision>s  = floating point seconds
        %E                   = label with E/W instead of +/-
        %N                   = label with N/S instead of +/-
 For example, the command `set format x "%Ddeg %5.2mmin %E"` will cause
 x coordinate -1.51 to be labeled as `" 1deg 30.60min W"`.

If the xtics are left in the default state (`set xtics numeric`) the coordinate
 will be reported as a decimal number of degrees, and `format` will be assumed
 to contain normal numeric format specifiers rather than the special set above.

To output degrees/minutes/seconds in a context other than axis tics, such as
 placing labels on a map, you can use the relative time format specifiers
 %tH %tM %tS for strptime.  See `time_specifiers`, `strptime`.
?set xtics logscale
?xtics logscale
 If the `logscale` attribute is set for a tic series along a log-scaled axis,
 the tic interval is interpreted as a multiplicative factor rather than a
 constant. For example:
      # generate a series of tics at y=20 y=200 y=2000 y=20000
      set log y
      set ytics 20, 10, 50000 logscale
 Note that no tic is placed at y=50000 because it is not in the series 2*10^x.
 If the logscale property is disabled, the tic increment will be treated as
 an additive constant even for a log-scaled axis.  For example:
      # generate a series of tics at y=20 y=40 y=60 ... y=200
      set log y
      set yrange [20:200]
      set ytics 20 nologscale
 The `logscale` attribute is set automatically by the `set log` command,
 so normally you do not need this keyword unless you want to force a
 constant tic interval as in the second example above.
?set xtics rangelimited
?xtics rangelimited
?rangelimited
?range-frame
 This option limits both the auto-generated axis tic labels and the
 corresponding plot border to the range of values actually present in the data
 that has been plotted.  Note that this is independent of the current range
 limits for the plot. For example, suppose that the data in "file.dat" all lies
 in the range 2 < y < 4.  Then the following commands will create a plot for
 which the left-hand plot border (y axis) is drawn for only this portion of the
 total y range, and only the axis tics in this region are generated.
 I.e., the plot will be scaled to the full range on y, but there will be a gap
 between 0 and 2 on the left border and another gap between 4 and 10. This
 style is sometimes referred to as a `range-frame` graph.
       set border 3
       set yrange [0:10]
       set ytics nomirror rangelimited
       plot "file.dat"
?commands set xyplane
?commands show xyplane
?set xyplane
?show xyplane
?xyplane
 The `set xyplane` command adjusts the position at which the xy plane is drawn
 in a 3D plot.  The synonym "set ticslevel" is accepted for backwards
 compatibility.

Syntax:
       set xyplane at <zvalue>
       set xyplane relative <frac>
       set ticslevel <frac>        # equivalent to set xyplane relative
       show xyplane

The form `set xyplane relative <frac>` places the xy plane below the range in
 Z, where the distance from the xy plane to Zmin is given as a fraction of the
 total range in z.  The default value is 0.5.  Negative values are permitted,
 but tic labels on the three axes may overlap.

The alternative form `set xyplane at <zvalue>` fixes the placement of the
 xy plane at a specific Z value regardless of the current z range. Thus to
 force the x, y, and z axes to meet at a common origin one would specify
 `set xyplane at 0`.

See also `set view`, and `set zeroaxis`.
?commands set xzeroaxis
?commands unset xzeroaxis
?commands show xzeroaxis
?set xzeroaxis
?unset xzeroaxis
?show xzeroaxis
?xzeroaxis
?noxzeroaxis
 The `set xzeroaxis` command draws a line at y = 0.  For details,
 please see `set zeroaxis`.
?commands set y2data
?commands show y2data
?set y2data
?show y2data
?y2data
 The `set y2data` command sets y2 (right-hand) axis data to timeseries
 (dates/times).  Please see `set xdata`.
?commands set y2dtics
?commands unset y2dtics
?set y2dtics
?unset y2dtics
?show y2dtics
?y2dtics
?noy2dtics
 The `set y2dtics` command changes tics on the y2 (right-hand) axis to days of
 the week.  Please see `set xdtics` for details.
?commands set y2label
?commands show y2label
?set y2label
?show y2label
?y2label
 The `set y2label` command sets the label for the y2 (right-hand) axis.
 Please see `set xlabel`.
?commands set y2mtics
?commands unset y2mtics
?commands show y2mtics
?set y2mtics
?unset y2mtics
?show y2mtics
?y2mtics
?noy2mtics
 The `set y2mtics` command changes tics on the y2 (right-hand) axis to months
 of the year.  Please see `set xmtics` for details.
?commands set y2range
?commands show y2range
?set y2range
?show y2range
?y2range
 The `set y2range` command sets the vertical range that will be displayed on
 the y2 (right) axis.  See `set xrange` for the full set of command options.
 See also `set link`.
?commands set y2tics
?commands unset y2tics
?commands show y2tics
?set y2tics
?unset y2tics
?show y2tics
?y2tics
?noy2tics
 The `set y2tics` command controls major (labeled) tics on the y2 (right-hand)
 axis.  Please see `set xtics` for details.
?commands set y2zeroaxis
?commands unset y2zeroaxis
?commands show y2zeroaxis
?set y2zeroaxis
?unset y2zeroaxis
?show y2zeroaxis
?y2zeroaxis
?noy2zeroaxis
 The `set y2zeroaxis` command draws a line at the origin of the y2 (right-hand)
 axis (x2 = 0).  For details, please see `set zeroaxis`.
?commands set ydata
?commands show ydata
?set ydata
?show ydata
?ydata
 The `set ydata` commands sets y-axis data to timeseries (dates/times).
 Please see `set xdata`.
?commands set ydtics
?commands unset ydtics
?commands show ydtics
?set ydtics
?unset ydtics
?show ydtics
?ydtics
?noydtics
 The `set ydtics` command changes tics on the y axis to days of the week.
 Please see `set xdtics` for details.
?commands set ylabel
?commands show ylabel
?set ylabel
?show ylabel
?ylabel
 This command sets the label for the y axis.  Please see `set xlabel`.
?commands set ymtics
?commands unset ymtics
?commands show ymtics
?set ymtics
?unset ymtics
?show ymtics
?ymtics
?noymtics
 The `set ymtics` command changes tics on the y axis to months of the year.
 Please see `set xmtics` for details.
?commands set yrange
?commands show yrange
?set yrange
?show yrange
?yrange
 The `set yrange` command sets the vertical range that will be displayed on
 the y axis.  Please see `set xrange` for details.
?commands set ytics
?commands unset ytics
?commands show ytics
?set ytics
?unset ytics
?show ytics
?ytics
?noytics
 The `set ytics` command controls major (labeled) tics on the y axis.
 Please see `set xtics` for details.
?commands set yzeroaxis
?commands unset yzeroaxis
?commands show yzeroaxis
?set yzeroaxis
?unset yzeroaxis
?show yzeroaxis
?yzeroaxis
?noyzeroaxis
 The `set yzeroaxis` command draws a line at x = 0.  For details,
 please see `set zeroaxis`.
?commands set zdata
?commands show zdata
?set zdata
?show zdata
?zdata
 The `set zdata` command sets zaxis data to timeseries (dates/times).
 Please see `set xdata`.
?commands set zdtics
?commands unset zdtics
?commands show zdtics
?set zdtics
?unset zdtics
?show zdtics
?zdtics
?nozdtics
 The `set zdtics` command changes tics on the z axis to days of the week.
 Please see `set xdtics` for details.
?commands set zzeroaxis
?commands unset zzeroaxis
?commands show zzeroaxis
?set zzeroaxis
?unset zzeroaxis
?show zzeroaxis
?zzeroaxis
?nozzeroaxis
 The `set zzeroaxis` command draws a line through (x=0,y=0).  This has no effect
 on 2D plots, including splot with `set view map`. For details, please
 see `set zeroaxis` and `set xyplane`.
?commands set cbdata
?commands show cbdata
?set cbdata
?show cbdata
?cbdata
 Set color box axis data to timeseries (dates/times).  Please see `set xdata`.
?commands set cbdtics
?commands unset cbdtics
?commands show cbdtics
?set cbdtics
?unset cbdtics
?show cbdtics
?cbdtics
?nocbdtics
 The `set cbdtics` command changes tics on the color box axis to days of the
 week. Please see `set xdtics` for details.
?commands set zero
?commands show zero
?set zero
?show zero
?zero
 The `zero` value is the default threshold for values approaching 0.0.

Syntax:
       set zero <expression>
       show zero

`gnuplot` will not plot a point if its imaginary part is greater in magnitude
 than the `zero` threshold.  This threshold is also used in various other
 parts of `gnuplot` as a (crude) numerical-error threshold.  The default
 `zero` value is 1e-8.  `zero` values larger than 1e-3 (the reciprocal of the
 number of pixels in a typical bitmap display) should probably be avoided, but
 it is not unreasonable to set `zero` to 0.0.
?commands set zeroaxis
?commands unset zeroaxis
?commands show zeroaxis
?set zeroaxis
?unset zeroaxis
?show zeroaxis
?zeroaxis
 The x axis may be drawn by `set xzeroaxis` and removed by `unset xzeroaxis`.
 Similar commands behave similarly for the y, x2, y2, and z axes.
 `set zeroaxis ...` (no prefix) acts on the x, y, and z axes jointly.

Syntax:
       set {x|x2|y|y2|z}zeroaxis { {linestyle | ls <line_style>}
                                  | {linetype | lt <line_type>}
                                    {linewidth | lw <line_width>}
                                    {linecolor | lc <colorspec>}
                                    {dashtype | dt <dashtype>} }
       unset {x|x2|y|y2|z}zeroaxis
       show {x|y|z}zeroaxis

By default, these options are off.  The selected zero axis is drawn
 with a line of type <line_type>, width <line_width>, color <colorspec>, and
 dash type <dashtype> (if supported by the terminal driver currently in use),
 or a user-defined style <line_style> (see `set style line`).

If no linetype is specified, any zero axes selected will be drawn
 using the axis linetype (linetype 0).

Examples:

To simply have the y=0 axis drawn visibly:

set xzeroaxis

If you want a thick line in a different color or pattern, instead:

set xzeroaxis linetype 3 linewidth 2.5
?commands set zlabel
?commands show zlabel
?set zlabel
?show zlabel
?zlabel
 This command sets the label for the z axis.  Please see `set xlabel`.
?commands set zmtics
?commands unset zmtics
?commands show zmtics
?set zmtics
?unset zmtics
?show zmtics
?zmtics
?nozmtics
 The `set zmtics` command changes tics on the z axis to months of the year.
 Please see `set xmtics` for details.
?commands set zrange
?commands show zrange
?set zrange
?show zrange
?zrange
 The `set zrange` command sets the range that will be displayed on the z axis.
 The zrange is used only by `splot` and is ignored by `plot`.  Please see
 `set xrange` for details.
?commands set ztics
?commands unset ztics
?commands show ztics
?set ztics
?unset ztics
?show ztics
?ztics
?noztics
 The `set ztics` command controls major (labeled) tics on the z axis.
 Please see `set xtics` for details.
?commands set cblabel
?commands show cblabel
?set cblabel
?show cblabel
?cblabel
 This command sets the label for the color box axis.  Please see `set xlabel`.
?commands set cbmtics
?commands unset cbmtics
?commands show cbmtics
?set cbmtics
?unset cbmtics
?show cbmtics
?cbmtics
?nocbmtics
 The `set cbmtics` command changes tics on the color box axis to months of the
 year. Please see `set xmtics` for details.
?commands set cbrange
?commands show cbrange
?set cbrange
?show cbrange
?cbrange
 The `set cbrange` command sets the range of values which are colored using
 the current `palette` by styles `with pm3d`, `with image` and `with palette`.
 Values outside of the color range use color of the nearest extreme.

If the cb-axis is autoscaled in `splot`, then the colorbox range is taken from
 `zrange`.  Points drawn in `splot ... pm3d|palette` can be filtered by using
 different `zrange` and `cbrange`.

Please see `set xrange` for details on `set cbrange` syntax. See also
 `set palette` and `set colorbox`.
?commands set cbtics
?commands unset cbtics
?commands show cbtics
?set cbtics
?unset cbtics
?show cbtics
?cbtics
?nocbtics
 The `set cbtics` command controls major (labeled) tics on the color box axis.
 Please see `set xtics` for details.
?commands shell
?shell
 The `shell` command spawns an interactive shell.  To return to `gnuplot`,
 type `logout` if using VMS, `exit` or the END-OF-FILE character if using
 Unix, or `exit` if using MS-DOS or OS/2.

The `shell` command ignores anything else on the gnuplot command line.
 If instead you want to pass a command string to a shell for immediate
 execution, use the `system` function or the shortcut `!`. See `system`.

Examples:

shell
       system "print previous_plot.ps"
       ! print previous_plot.ps
       current_time = system("date")

?commands splot
?splot
 `splot` is the command for drawing 3D plots (well, actually projections on a 2D
 surface, but you knew that).  It is the 3D equivalent of the `plot` command.
 `splot` provides only a single x, y, and z axis; there is no equivalent to the
 x2 and y2 secondary axes provided by `plot`.

See the `plot` command for many options available in both 2D and 3D plots.

Syntax:
       splot {<ranges>}
             {<iteration>}
             <function> | {{<file name> | <datablock name>} {datafile-modifiers}}
                        | <voxelgridname>
                        | keyentry
             {<title-spec>} {with <style>}
             {, {definitions{,}} <function> ...}

The `splot` command operates on a data generated by a function, read from
 a data file, or stored previously in a named data block.  Data file names
 are usually provided as a quoted string.  The function can be a mathematical
 expression, or a triple of mathematical expressions in parametric mode.

A new feature in version 5.4 is that `splot` can operate on voxel data.
 See `voxel-grids`, `set vgrid`, `vxrange`.  At present voxel grids can be
 be plotted using styles `with dots`, `with points`, or `with isosurface`.
 Voxel grid values can also be referenced in the `using` specifiers of other
 plot styles, for example to assign colors.

By default `splot` draws the xy plane completely below the plotted data.
 The offset between the lowest ztic and the xy plane can be changed by `set
 xyplane`.  The orientation of a `splot` projection is controlled by
 `set view`.  See `set view` and `set xyplane` for more information.

The syntax for setting ranges on the `splot` command is the same as for `plot`.
 In non-parametric mode, ranges must be given in the order
       splot [<xrange>][<yrange>][<zrange>] ...
 In parametric mode, the order is
       splot [<urange>][<vrange>][<xrange>][<yrange>][<zrange>] ...

The `title` option is the same as in `plot`.  The operation of `with` is also
 the same as in `plot` except that not all 2D plotting styles are available.

The `datafile` options have more differences.

As an alternative to surfaces drawn using parametric or function mode, the
 pseudo-file '++' can be used to generate samples on a grid in the xy plane.

See also `show plot`, `set view map`, and `sampling`.
?commands splot datafile
?splot datafile
 `Splot`, like `plot`, can display from a file.

Syntax:
       splot '<file_name>' {binary <binary list>}
                           {{nonuniform} matrix}
                           {index <index list>}
                           {every <every list>}
                           {using <using list>}

The special filenames `""` and `"-"` are permitted, as in `plot`.
 See `special-filenames`.

In brief, `binary` and `matrix` indicate that the data are in a special
 form, `index` selects which data sets in a multi-data-set file are to be
 plotted, `every` specifies which datalines (subsets) within a single data
 set are to be plotted, and `using` determines how the columns within a single
 record are to be interpreted.

The options `index` and `every` behave the same way as with `plot`;  `using`
 does so also, except that the `using` list must provide three entries
 instead of two.

The `plot` option `smooth` is not available for `splot`, but
 `cntrparam` and `dgrid3d` provide limited smoothing capabilities.

Data file organization is essentially the same as for `plot`, except that
 each point is an (x,y,z) triple.  If only a single value is provided, it
 will be used for z, the block number will be used for y, and the index
 of the data point in the block will be used for x.  If two or four values
 are provided, `gnuplot` uses the last value for calculating the color in
 pm3d plots.  Three values are interpreted as an (x,y,z) triple.  Additional
 values are generally used as errors, which can be used by `fit`.

Single blank records separate blocks of data in a `splot` datafile; `splot`
 treats blocks as the equivalent of function y-isolines.  No line will join
 points separated by a blank record.  If all blocks contain the same number of
 points, `gnuplot` will draw cross-isolines between points in the blocks,
 connecting corresponding points.  This is termed "grid data", and is required
 for drawing a surface, for contouring (`set contour`) and hidden-line removal
 (`set hidden3d`). See also `splot grid_data`.

It is no longer necessary to specify `parametric` mode for three-column
 `splot`s.
?commands plot datafile matrix
?commands splot datafile matrix
?plot datafile matrix
?splot datafile matrix
?binary matrix
?matrix
 Gnuplot can interpret matrix data input in two different ways.

The first of these assumes a uniform grid of x and y coordinates and assigns
 each value in the input matrix to one element M[i,j] of this uniform grid.
 The assigned x coordinates are the integers [0:NCOLS-1].
 The assigned y coordinates are the integers [0:NROWS-1].
 This is the default for text data input, but not for binary input.
 See `matrix uniform` for examples and additional keywords.

The second interpretation assumes a non-uniform grid with explicit x and y
 coordinates. The first row of input data contains the y coordinates;
 the first column of input data contains the x coordinates.  For binary input
 data, the first element of the first row must contain the number of columns.
 This is the default for `binary matrix` input, but requires an additional
 keyword `nonuniform` for text input data.
 See `matrix nonuniform` for examples.

?commands plot datafile matrix uniform
?commands splot datafile matrix uniform
?datafile matrix uniform
?matrix uniform
?binary matrix uniform
 Example commands for plotting uniform matrix data:
      splot 'file' matrix using 1:2:3          # text input
      splot 'file' binary general using 1:2:3  # binary input

In a uniform grid matrix the z-values are read in a row at a time, i. e.,
     z11 z12 z13 z14 ...
     z21 z22 z23 z24 ...
     z31 z32 z33 z34 ...
 and so forth.

For text input, if the first row contains column labels rather than data,
 use the additional keyword `columnheaders`.   Similarly if the first field
 in each row contains a label rather than data, use the additional keyword
 `rowheaders`.  Here is an example that uses both:
     $DATA << EOD
     xxx A   B   C   D
     aa  z11 z12 z13 z14
     bb  z21 z22 z23 z24
     cc  z31 z32 z33 z34
     EOD
     plot $DATA matrix columnheaders rowheaders with image

For text input, a blank line or comment line ends the matrix, and starts a new
 data block.  You can select among the data blocks in a file by the `index`
 option to the `splot` command, as usual.  The columnheaders option, if present,
 is applied only to the first data block.
?commands plot datafile matrix nonuniform
?commands splot datafile matrix nonuniform
?datafile matrix nonuniform
?matrix nonuniform
?binary matrix nonuniform
 The first row of input data contains the y coordinates.
 The first column of input data contains the x coordinates.
 For binary input data, the first field of the first row must contain the
 number of columns. (This number is ignored for text input).

Example commands for plotting non-uniform matrix data:
      splot 'file' nonuniform matrix using 1:2:3  # text input
      splot 'file' binary matrix using 1:2:3      # binary input

Thus the data organization for non-uniform matrix input is

<N+1>  <x0>   <x1>   <x2>  ...  <xN>
        <y0> <z0,0> <z0,1> <z0,2> ... <z0,N>
        <y1> <z1,0> <z1,1> <z1,2> ... <z1,N>
         :      :      :      :   ...    :

which is then converted into triplets:
       <x0> <y0> <z0,0>
       <x0> <y1> <z0,1>
       <x0> <y2> <z0,2>
        :    :     :
       <x0> <yN> <z0,N>

<x1> <y0> <z1,0>
       <x1> <y1> <z1,1>
        :    :     :

These triplets are then converted into `gnuplot` iso-curves and then
 `gnuplot` proceeds in the usual manner to do the rest of the plotting.
?datafile matrix every
?matrix every
 The `every` keyword has special meaning when used with matrix data.
 Rather than applying to blocks of single points, it applies to rows and
 column values.  Note that matrix rows and columns are indexed starting
 from 0, so the row with index N is the (N+1)th row.
 Syntax:
       plot 'file' every {<column_incr>}
                           {:{<row_incr>}
                             {:{<start_column>}
                               {:{<start_row>}
                                 {:{<end_column>}
                                   {:<end_row>}}}}}
 Examples:
       plot 'file' matrix every :::N::N   # plot all values in row with index N
       plot 'file' matrix every ::3::7    # plot columns 3 to 7 for all rows
       plot 'file' matrix every ::3:0:7:4 # submatrix bounded by [3,0] and [7,4]
?commands plot datafile matrix examples
?commands splot datafile matrix examples
?datafile matrix examples
?matrix examples
?binary matrix examples
 A collection of matrix and vector manipulation routines (in C) is provided
 in `binary.c`.  The routine to write binary data is

int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)

An example of using these routines is provided in the file `bf_test.c`, which
 generates binary files for the demo file `demo/binary.dem`.

Usage in `plot`:
     plot `a.dat` matrix
     plot `a.dat` matrix using 1:3
     plot 'a.gpbin' {matrix} binary using 1:3
 will plot rows of the matrix, while using 2:3 will plot matrix columns, and
 using 1:2 the point coordinates (rather useless). Applying the `every` option
 you can specify explicit rows and columns.

Example -- rescale axes of a matrix in a text file:
     splot `a.dat` matrix using (1+$1):(1+$2*10):3

Example -- plot the 3rd row of a matrix in a text file:
     plot 'a.dat' matrix using 1:3 every 1:999:1:2
 (rows are enumerated from 0, thus 2 instead of 3).

Gnuplot can read matrix binary files by use of the option `binary` appearing
 without keyword qualifications unique to general binary, i.e., `array`,
 `record`, `format`, or `filetype`.  Other general binary keywords for
 translation should also apply to matrix binary.  (See `binary general` for
 more details.)
?commands splot datafile example
?splot datafile example
?splot example
 A simple example of plotting a 3D data file is

splot 'datafile.dat'

where the file "datafile.dat" might contain:

# The valley of the Gnu.
          0 0 10
          0 1 10
          0 2 10

1 0 10
          1 1 5
          1 2 10

2 0 10
          2 1 1
          2 2 10

3 0 10
          3 1 0
          3 2 10

Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of 3 points each ).
 Rows (blocks) are separated by blank records.

Note also that the x value is held constant within each dataline.  If you
 instead keep y constant, and plot with hidden-line removal enabled, you will
 find that the surface is drawn 'inside-out'.

Actually for grid data it is not necessary to keep the x values constant
 within a block, nor is it necessary to keep the same sequence of y
 values.  `gnuplot` requires only that the number of points be the same for
 each block.  However since the surface mesh, from which contours are
 derived, connects sequentially corresponding points, the effect of an
 irregular grid on a surface plot is unpredictable and should be examined
 on a case-by-case basis.
?commands splot grid_data
?splot grid_data
?grid_data
 The 3D routines are designed for points in a grid format, with one sample,
 datapoint, at each mesh intersection; the datapoints may originate from
 either evaluating a function, see `set isosamples`, or reading a datafile,
 see `splot datafile`.  The term "isoline" is applied to the mesh lines for
 both functions and data.  Note that the mesh need not be rectangular in x
 and y, as it may be parameterized in u and v, see `set isosamples`.

However, `gnuplot` does not require that format.  In the case of functions,
 'samples' need not be equal to 'isosamples', i.e., not every x-isoline
 sample need intersect a y-isoline. In the case of data files, if there
 are an equal number of scattered data points in each block, then
 "isolines" will connect the points in a block, and "cross-isolines"
 will connect the corresponding points in each block to generate a
 "surface".  In either case, contour and hidden3d modes may give different
 plots than if the points were in the intended format.  Scattered data can be
 converted to a {different} grid format with `set dgrid3d`.

The contour code tests for z intensity along a line between a point on a
 y-isoline and the corresponding point in the next y-isoline.  Thus a `splot`
 contour of a surface with samples on the x-isolines that do not coincide with
 a y-isoline intersection will ignore such samples. Try:
        set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
        set style function lp
        set contour
        set isosamples 10,10; set samples 10,10;
        splot cos(x)*cos(y)
        set samples 4,10; replot
        set samples 10,4; replot

?commands splot surfaces
?splot surfaces
 `splot` can display a surface as a collection of points, or by connecting
 those points.  As with `plot`, the points may be read from a data file or
 result from evaluation of a function at specified intervals, see
 `set isosamples`.  The surface may be approximated by connecting the points
 with straight line segments, see `set surface`, in which case the surface
 can be made opaque with `set hidden3d.`  The orientation from which the 3d
 surface is viewed can be changed with `set view`.

Additionally, for points in a grid format, `splot` can interpolate points
 having a common amplitude (see `set contour`) and can then connect those
 new points to display contour lines, either directly with straight-line
 segments or smoothed lines (see `set cntrparam`).  Functions are already
 evaluated in a grid format, determined by `set isosamples` and `set samples`,
 while file data must either be in a grid format, as described in `data-file`,
 or be used to generate a grid (see `set dgrid3d`).

Contour lines may be displayed either on the surface or projected onto the
 base.  The base projections of the contour lines may be written to a
 file, and then read with `plot`, to take advantage of `plot`'s additional
 formatting capabilities.
?commands splot voxel-grid
?splot voxel-grids
?voxel-grids
 Syntax:
      splot $voxelgridname with {dots|points} {above <threshold>} ...
      splot $voxelgridname with isosurface {level <threshold>} ...

Voxel data can be plotted with dots or points marking individual voxels whose
 value is above the specified threshold value (default threshold = 0).
 Color/pointtype/linewidth properties can be appended as usual.

At many view angles the voxel grid points will occlude each other or create
 Moiré artifacts on the display. These effects can be avoided by introducing
 jitter so that the displayed dot or point is displaced randomly from the
 true voxel grid coordinate. See `set jitter`.

Dense voxel grids can be down-sampled by using the `pointinterval` property
 (`pi` for short) to reduce the number of points drawn.
      splot $vgrid with points pointtype 6 pointinterval 2

`with isosurface` will create a tessellated surface in 3D enclosing all voxels
 with value greater than the requested threshold. The surface placement is
 adjusted by linear interpolation to pass through the threshold value itself.

See `set vgrid`, `vfill`.
 See demos `vplot.dem`, `isosurface.dem`.

?commands stats
?stats
?statistics
 Syntax:
      stats {<ranges>} 'filename' {matrix | using N{:M}} {name 'prefix'} {{no}output}

This command prepares a statistical summary of the data in one or two columns
 of a file. The using specifier is interpreted in the same way as for plot
 commands. See `plot` for details on the `index`, `every`, and `using`
 directives. Data points are filtered against both xrange and yrange before
 analysis. See `set xrange`. The summary is printed to the screen by default.
 Output can be redirected to a file by prior use of the command `set print`,
 or suppressed altogether using the `nooutput` option.

In addition to printed output, the program stores the individual statistics
 into three sets of variables.
 The first set of variables reports how the data is laid out in the file:
 The array of column headers is generated only if option
 `set datafile columnheaders` is in effect.
      STATS_records           # total number N of in-range data records (N)
      STATS_outofrange        # number of records filtered out by range limits
      STATS_invalid           # number of invalid/incomplete/missing records
      STATS_blank             # number of blank lines in the file
      STATS_blocks            # number of indexable blocks of data in the file
      STATS_columns           # number of data columns in the first row of data
      STATS_column_header     # array of strings holding column headers found

The second set reports properties of the in-range data from a single column.
 This column is treated as y. If the y axis is autoscaled then no range limits
 are applied. Otherwise only values in the range [ymin:ymax] are considered.

If two columns are analysed jointly by a single `stats` command, the suffix
 "_x" or "_y" is appended to each variable name.
 I.e. STATS_min_x is the minimum value found in the first column, while
 STATS_min_y is the minimum value found in the second column.
 In this case points are filtered by testing against both xrange and yrange.

STATS_min               # minimum value of in-range data points
      STATS_max               # maximum value of in-range data points
      STATS_index_min         # index i for which data[i] == STATS_min
      STATS_index_max         # index i for which data[i] == STATS_max
      STATS_lo_quartile       # value of the lower (1st) quartile boundary
      STATS_median            # median value
      STATS_up_quartile       # value of the upper (3rd) quartile boundary
      STATS_mean              # mean value of the in-range data points
      STATS_ssd               # sample standard deviation of the in-range data
                                   = sqrt( Sum[(y-ymean)^2] / (N-1) )
      STATS_stddev            # population standard deviation of the in-range data
                                   = sqrt( Sum[(y-ymean)^2] / N )
      STATS_sum               # sum
      STATS_sumsq             # sum of squares
      STATS_skewness          # skewness of the in-range data points
      STATS_kurtosis          # kurtosis of the in-range data points
      STATS_adev              # mean absolute deviation of the in-range data points
      STATS_mean_err          # standard error of the mean value
      STATS_stddev_err        # standard error of the standard deviation
      STATS_skewness_err      # standard error of the skewness
      STATS_kurtosis_err      # standard error of the kurtosis

The third set of variables is only relevant to analysis of two data columns.
      STATS_correlation       # sample correlation coefficient between x and y values
      STATS_slope             # A corresponding to a linear fit y = Ax + B
      STATS_slope_err         # uncertainty of A
      STATS_intercept         # B corresponding to a linear fit y = Ax + B
      STATS_intercept_err     # uncertainty of B
      STATS_sumxy             # sum of x*y
      STATS_pos_min_y         # x coordinate of a point with minimum y value
      STATS_pos_max_y         # x coordinate of a point with maximum y value

Keyword `matrix` indicates that the input consists of a matrix (see `matrix`);
 the usual statistics are generated by considering all matrix elements.
 The matrix dimensions are saved in variables STATS_size_x and STATS_size_y.
      STATS_size_x            # number of matrix columns
      STATS_size_y            # number of matrix rows

The index reported in STATS_index_xxx corresponds to the value of pseudo-column
 0 ($0) in plot commands.  I.e. the first point has index 0, the last point
 has index N-1.

Data values are sorted to find the median and quartile boundaries.
 If the total number of points N is odd, then the median value is taken as the
 value of data point (N+1)/2. If N is even, then the median is reported as the
 mean value of points N/2 and (N+2)/2. Equivalent treatment is used for the
 quartile boundaries.

For an example of using the `stats` command to annotate a subsequent plot, see
 stats.dem.

The `stats` command in this version of gnuplot can handle log-scaled data, but
 not the content of time/date fields (`set xdata time` or `set ydata time`).
 This restriction may be relaxed in a future version.
?stats name
?statistics name
 It may be convenient to track the statistics from more than one file or data
 column in parallel. The `name` option causes the default prefix "STATS" to be
 replaced by a user-specified string.  For example, the mean value of column 2
 data from two different files could be compared by
      stats "file1.dat" using 2 name "A"
      stats "file2.dat" using 2 name "B"
      if (A_mean < B_mean) {...}

Instead of providing a string constant as the name, the keyword `columnheader`
 or function `columnheader(N)` can be used to generate the name from whatever
 string is found in that column in the first row of the data file:
      do for [COL=5:8] { stats 'datafile' using COL name columnheader }

?commands system
?system
 Syntax:
       system "command string"
       ! command string
       output = system("command string")
       show variable GPVAL_SYSTEM

`system "command"` executes "command" in a subprocess by invoking the
 operating system's default shell.  If called as a function, `system("command")`
 returns the character stream from the subprocess's stdout as a string.
 One trailing newline is stripped from the resulting string if present.
 See also `backquotes`.

The exit status of the subprocess is reported in variables GPVAL_SYSTEM_ERRNO
 and GPVAL_SYSTEM_ERRMSG.  Note that if the command string invokes more than
 one programs, the subprocess may return "Success" even if one of the programs
 produced an error.  E.g. file = system("ls -1 *.plt | tail -1") will return
 "Success" even if there are no *.plt files because `tail` succeeds even if `ls`
 does not.

The system command can be used to import external functions into gnuplot as
 shown below, however this will force creation of a separate subprocess every
 time the function is invoked. For functions that will be invoked many times
 it would be better to import a directly callable subroutine from a shared
 library.  See `import` and `plugin.dem`.

f(x) = real(system(sprintf("somecommand %f", x)))
?commands test
?test palette
?test
 This command graphically tests or presents terminal and palette capabilities.

Syntax:
       test {terminal | palette}

`test` or `test terminal` creates a display of line and point styles and other
 useful things supported by the `terminal` you are currently using.

`test palette` plots profiles of R(z),G(z),B(z), where 0<=z<=1. These are the
 RGB components of the current color `palette`. It also plots the apparent net
 intensity as calculated using NTSC coefficients to map RGB onto a grayscale.
 The profile values are also loaded into a datablock named $PALETTE.
?commands toggle
?toggle
 Syntax:
       toggle {<plotno> | "plottitle" | all}

This command has the same effect as left-clicking on the key entry for a plot
 currently displayed by an interactive terminal (qt, wxt, x11). If the plot is
 showing, it is toggled off;  if it is currently hidden, it is toggled on.
 `toggle all` acts on all active plots, equivalent to the hotkey "i".
 `toggle "title"` requires an exact match to the plot title.  `toggle "ti*"`
 acts on the first plot whose title matches the characters before the final '*'.
 If the current terminal is not interactive, the toggle command has no effect.
?commands undefine
?undefine
 Clear one or more previously defined user variables.  This is useful in order
 to reset the state of a script containing an initialization test.

A variable name can contain the wildcard character `*` as last character. If the
 wildcard character is found, all variables with names that begin with the prefix
 preceding the wildcard will be removed. This is useful to remove several variables
 sharing a common prefix. Note that the wildcard character is only allowed at the
 end of the variable name! Specifying the wildcard character as sole argument to
 `undefine` has no effect.

Example:

undefine foo foo1 foo2
       if (!exists("foo")) load "initialize.gp"

bar = 1; bar1 = 2; bar2 = 3
       undefine bar*                 # removes all three variables

?commands unset
?unset
 Options set using the `set` command may be returned to their default state by
 the corresponding `unset` command.  The `unset` command may contain an optional
 iteration clause. See `plot for`.

Examples:
       set xtics mirror rotate by -45 0,10,100
       ...
       unset xtics

# Unset labels numbered between 100 and 200
       unset for [i=100:200] label i
?unset linetype
 Syntax:
       unset linetype N
 Remove all characteristics previously associated with a single linetype.
 Subsequent use of this linetype will use whatever characteristics and color
 that is native to the current terminal type (i.e. the default linetypes
 properties available in gnuplot versions prior to 4.6).
?unset monochrome
 Switches the active set of linetypes from monochrome to color.
 Equivalent to `set color`.
?unset output
 Because some terminal types allow multiple plots to be written into a single
 output file, the output file is not automatically closed after plotting.
 In order to print or otherwise use the file safely, it should first be closed
 explicitly by using `unset output` or by using `set output` to close the
 previous file and then open a new one.
?unset terminal
 The default terminal that is active at the time of program entry depends on the
 system platform, gnuplot build options, and the environmental variable GNUTERM.
 Whatever this default may be, gnuplot saves it to internal variable GNUTERM.
 The `unset terminal` command restores the initial terminal type.
 It is equivalent to `set terminal GNUTERM`.  However if the string in GNUTERM
 contains terminal options in addition to the bare terminal name, you may want
 to instead use `set terminal @GNUTERM`.
?commands update
?update
 Note: This command is DEPRECATED.  Use `save fit` instead.
?commands vclear
?vclear
 Syntax:
      vclear {$gridname}
 Resets the value of all voxels in an existing grid to zero.
 If no grid name is given, clears the currently active grid.
?commands vfill
?vfill
?VoxelDistance
 Syntax:
      vfill FILE using x:y:z:radius:(<expression>)

The `vfill` command acts analogously to a `plot` command except that instead
 of creating a plot it modifies voxels in the currently active voxel grid.
 For each point read from the input file, the voxel containing that point and
 also all other voxels within a sphere of given radius centered about (x,y,z)
 are incremented as follows:
 *  user variable VoxelDistance is set to the distance from (x,y,z) to that
    voxel's grid coordinates (vx,vy,vz).
 *  The expression provided in the 5th `using` specifier is evaluated.
    This expression can use the new value of VoxelDistance.
 *  voxel(vx,vy,vz) += result of evaluating <expression>
 Example:
      vfill "file.dat" using 1:2:3:(3.0):(1.0)
 This command adds 1 to the value of every voxel within a sphere of radius 3.0
 around each point in file.dat.

Example:
      vfill "file.dat" using 1:2:3:4:(VoxelDistance < 1 ? 1 : 1/VoxelDistance)
 This command modifies all voxels in a sphere whose radius is determined for
 each point by the content of column 4.  The increment added to a voxel
 decreases with its distance from the data point.

Note that `vfill` always increments existing values in the current voxel grid.
 To reset them to zero, use `vclear`.
?while
?commands while
 Syntax:
       while (<expr>) {
           <commands>
       }
 Execute a block of commands repeatedly so long as <expr> evaluates to
 a non-zero value.  This command cannot be mixed with old-style (un-bracketed)
 if/else statements.  See also `do`, `continue`, `break`.
?complete list of terminals
?terminal
?term
 Gnuplot supports a large number of output formats. These are selected by
 choosing an appropriate terminal type, possibly with additional modifying
 options. See `set terminal`.

This document may describe terminal types that are not available to you
 because they were not configured or installed on your system. To see a list of
 terminals available on a particular gnuplot installation, type 'set terminal'
 with no modifiers.

Terminals marked `legacy` are not built by default in recent gnuplot versions
 and may not actually work.
?set terminal linux
?set terminal vgagl
?linux console
?console
 Older gnuplot versions required special terminals `linux` or `vgagl`
 in order to display graphics on the linux console, i.e. in the absence of
 X11 or other windowing environment.  These terminals have been deprecated.

The recommended way to run gnuplot from the linux console is now to use a
 console terminal emulator such as yaft (https://github.com/uobikiemukot/yaft)
 that supports sixel graphics.  With yaft as your console terminal you can
 run gnuplot and select a terminal with sixel output. See `sixelgd`.
 As a fall-back option you could use `set term dumb`, but sixel graphics
 are much nicer.
?commands set terminal tek410x
?set terminal tek410x
?set term tek410x
?terminal tek410x
?term tek410x
?tek410x
 The `tek410x` terminal driver supports the 410x and 420x family of Tektronix
 terminals.  It has no options.
?commands set terminal tek40xx
?set terminal tek40xx
?set term tek40xx
?terminal tek40xx
?term tek40xx
?tek40
?commands set terminal vttek
?set terminal vttek
?set term vttek
?terminal vttek
?term vttek
?vttek
?commands set terminal xterm
?set terminal xterm
?set term xterm
?terminal xterm
?term xterm
?xterm
?commands set terminal sixeltek
?set terminal sixeltek
?set term sixeltek
?terminal sixeltek
?term sixeltek
?sixeltek
 Syntax:
    set terminal sixeltek {<fontsize>} {color|mono} {size <x>,<y>}

The `sixel` output format was originally used by DEC terminals and printers.
 For use with xterm emulation, xterm must be compiled/configured with
 "--enable-sixel-graphics" and started with "-ti 340" on the command line.
 Menu option "sixelScrolling" should be selected. xterm/vt340 emulation
 limits plots to 16 simultaneous colors, but other emulators may permit more.

Note that gnuplot also supports another sixel output terminal, sixelgd,
 that offers more options and features. This family of terminal drivers supports a variety of VT-like terminals.
 `tek40xx` supports Tektronix 4010 and others as well as most TEK emulators.
 `vttek` supports VT-like tek40xx terminal emulators.
 The following are present only if selected when gnuplot is built:
 `kc-tek40xx` supports MS-DOS Kermit Tek4010 terminal emulators in color;
 `km-tek40xx` supports them in monochrome. `selanar` supports Selanar graphics.
 `bitgraph` supports BBN Bitgraph terminals.
 None have any options.
?commands set terminal x11
?set terminal x11
?set term x11
?terminal x11
?term x11
?x11
?X11

Syntax:
    set terminal x11 {<n> | window "<string>"}
                     {title "<string>"}
                     {{no}enhanced} {font <fontspec>}
                     {linewidth LW}
                     {{no}persist} {{no}raise} {{no}ctrlq}
                     {{no}replotonresize}
                     {close}
                     {size XX,YY} {position XX,YY}
    set terminal x11 {reset}

Multiple plot windows are supported: `set terminal x11 <n>` directs the
 output to plot window number n.  If n is not 0, the terminal number will be
 appended to the window title (unless a title has been supplied manually)
 and the icon will be labeled `Gnuplot <n>`.  The active window may be
 distinguished by a change in cursor (from default to crosshair).

The `x11` terminal can connect to X windows previously created by an outside
 application via the option `window` followed by a string containing the
 X ID for the window in hexadecimal format.  Gnuplot uses that external X
 window as a container since X does not allow for multiple clients selecting
 the ButtonPress event.  In this way, gnuplot's mouse features work within
 the contained plot window.

set term x11 window "220001e"

The x11 terminal supports enhanced text mode (see `enhanced`), subject
 to the available fonts. In order for font size commands embedded in text
 to have any effect, the default x11 font must be scalable. Thus the first
 example below will work as expected, but the second will not.

set term x11 enhanced font "arial,15" 
    set title '{/=20 Big} Medium {/=5 Small}'

set term x11 enhanced font "terminal-14" 
    set title '{/=20 Big} Medium {/=5 Small}'

Plot windows remain open even when the `gnuplot` driver is changed to a
 different device.  A plot window can be closed by pressing the letter q
 while that window has input focus, or by choosing `close` from a window
 manager menu.  All plot windows can be closed by specifying `reset`, which
 actually terminates the subprocess which maintains the windows (unless
 `-persist` was specified).  The `close` command can be used to close
 individual plot windows by number.  However, after a `reset`, those plot
 windows left due to persist cannot be closed with the command `close`.
 A `close` without a number closes the current active plot window.

The gnuplot outboard driver, gnuplot_x11, is searched in a default place
 chosen when the program is compiled.  You can override that by defining
 the environment variable GNUPLOT_DRIVER_DIR to point to a different
 location.

Plot windows will automatically be closed at the end of the session
 unless the `-persist` option was given.

The options `persist` and `raise` are unset by default, which means that
 the defaults (persist == no and raise == yes) or the command line options
 -persist / -raise or the Xresources are taken.  If [no]persist or
 [no]raise are specified, they will override command line options and
 Xresources.  Setting one of these options takes place immediately, so
 the behaviour of an already running driver can be modified.  If the window
 does not get raised, see discussion in `raise`.

The option `replotonresize` (active by default) replots the data when the
 plot window is resized. Without this option, the even-aspect-ratio scaling
 may result in the plot filling only part of the window after resizing.
 With this option, gnuplot does a full replot on each resize event, resulting
 in better space utilization. This option is generally desirable, unless the
 potentially CPU-intensive replotting during resizing is a concern. Replots
 can be manually initiated with hotkey 'e' or the 'replot' command.

The option `title "<title name>"` will supply the title name of the window
 for the current plot window or plot window <n> if a number is given.
 Where (or if) this title is shown depends on your X window manager.

The size option can be used to set the size of the plot window.  The
 size option will only apply to newly created windows.

The position option can be used to set the position of the plot window.  The
 position option will only apply to newly created windows.

The size or aspect ratio of a plot may be changed by resizing the `gnuplot`
 window.

Linewidths and pointsizes may be changed from within `gnuplot` with
 `set linestyle`.

For terminal type `x11`, `gnuplot` accepts (when initialized) the standard
 X Toolkit options and resources such as geometry, font, and name from the
 command line arguments or a configuration file.  See the X(1) man page
 (or its equivalent) for a description of such options.

A number of other `gnuplot` options are available for the `x11` terminal.
 These may be specified either as command-line options when `gnuplot` is
 invoked or as resources in the configuration file ".Xdefaults".  They are
 set upon initialization and cannot be altered during a `gnuplot` session.
 (except `persist` and `raise`)
?commands set terminal x11 x11_fonts
?set terminal x11 x11_fonts
?set term x11 x11_fonts
?x11 x11_fonts
?x11_fonts
 Upon initial startup, the default font is taken from the X11 resources
 as set in the system or user .Xdefaults file or on the command line.

Example:
       gnuplot*font: lucidasans-bold-12
 A new default font may be specified to the x11 driver from inside
 gnuplot using
      `set term x11 font "<fontspec>"`
 The driver first queries the X-server for a font of the exact name given.
 If this query fails, then it tries to interpret <fontspec> as
 "<font>,<size>,<slant>,<weight>" and to construct a full X11 font name
 of the form
       -*-<font>-<weight>-<s>-*-*-<size>-*-*-*-*-*-<encoding>

<font> is the base name of the font (e.g. Times or Symbol)
  <size> is the point size (defaults to 12 if not specified)
  <s> is `i` if <slant>=="italic" `o` if <slant>=="oblique" `r` otherwise
  <weight> is `medium` or `bold` if explicitly requested, otherwise `*`
  <encoding> is set based on the current character set (see `set encoding`).
 So `set term x11 font "arial,15,italic"` will be translated to
 -*-arial-*-i-*-*-15-*-*-*-*-*-iso8859-1 (assuming default encoding).
 The <size>, <slant>, and <weight> specifications are all optional.
 If you do not specify <slant> or <weight> then you will get whatever font 
 variant the font server offers first.
 You may set a default encoding via the corresponding X11 resource. E.g.
       gnuplot*encoding: iso8859-15
 The driver also recognizes some common PostScript font names and
 replaces them with possible X11 or TrueType equivalents.
 This same sequence is used to process font requests from `set label`.

If your gnuplot was built with configuration option --enable-x11-mbfonts,
 you can specify multi-byte fonts by using the prefix "mbfont:" on the font
 name. An additional font may be given, separated by a semicolon.
 Since multi-byte font encodings are interpreted according to the locale
 setting, you must make sure that the environmental variable LC_CTYPE is set
 to some appropriate locale value such as ja_JP.eucJP, ko_KR.EUC, or zh_CN.EUC.

Example:
       set term x11 font 'mbfont:kana14;k14'
             # 'kana14' and 'k14' are Japanese X11 font aliases, and ';'
             # is the separator of font names.
       set term x11 font 'mbfont:fixed,16,r,medium'
             # <font>,<size>,<slant>,<weight> form is also usable.
       set title '(mb strings)' font 'mbfont:*-fixed-medium-r-normal--14-*'

The same syntax applies to the default font in Xresources settings,
 for example,
       gnuplot*font: \
           mbfont:-misc-fixed-medium-r-normal--14-*-*-*-c-*-jisx0208.1983-0

If gnuplot is built with --enable-x11-mbfonts, you can use two special
 PostScript font names 'Ryumin-Light-*' and 'GothicBBB-Medium-*' (standard
 Japanese PS fonts) without the prefix "mbfont:".

?commands set terminal x11 command-line-options
?set terminal x11 command-line-options
?set term x11 command-line-options
?x11 command-line-options
 In addition to the X Toolkit options, the following options may be specified
 on the command line when starting `gnuplot` or as resources in your
 ".Xdefaults" file (note that `raise` and `persist` can be overridden
 later by `set term x11 [no]raise [no]persist)`:
  `-mono`     forces monochrome rendering on color displays.
  `-gray`     requests grayscale rendering on grayscale or color displays.
              (Grayscale displays receive monochrome rendering by default.)
  `-clear`    requests that the window be cleared momentarily before a
              new plot is displayed.
  `-tvtwm`    requests that geometry specifications for position of the
              window be made relative to the currently displayed portion
              of the virtual root.
  `-raise`    raises plot window after each plot
  `-noraise`  does not raise plot window after each plot
  `-ctrlq   ` closes window on ctrl-q rather than q
  `-persist`  plot windows survive after main gnuplot program exits
 The options are shown above in their command-line syntax.  When entered as
 resources in ".Xdefaults", they require a different syntax.

Example:
       gnuplot*gray:  on
       gnuplot*ctrlq: on

`gnuplot` also provides a command line option (`-pointsize <v>`) and a
 resource, `gnuplot*pointsize: <v>`, to control the size of points plotted
 with the `points` plotting style.  The value `v` is a real number (greater
 than 0 and less than or equal to ten) used as a scaling factor for point
 sizes.  For example, `-pointsize 2` uses points twice the default size, and
 `-pointsize 0.5` uses points half the normal size.

The `-ctrlq` switch changes the hot-key that closes a plot window from `q`
 to `<ctrl>q`. This is useful is you are using the keystroke-capture feature
 `pause mouse keystroke`, since it allows the character `q` to be captured
 just as all other alphanumeric characters. The `-ctrlq` switch similarly
 replaces the <space> hot-key with <ctrl><space> for the same reason.

?set terminal x11 color_resources
?set term x11 color_resources
?x11 color_resources
 NB: THIS SECTION IS LARGELY IRRELEVANT IN GNUPLOT VERSION 5
 The X11 terminal honors the following resources (shown here with their
 default values) or the greyscale resources.  The values may be color names
 as listed in the X11 rgb.txt file on your system, hexadecimal RGB color
 specifications (see X11 documentation), or a color name followed by a comma
 and an `intensity` value from 0 to 1.  For example, `blue, 0.5` means a half
 intensity blue.
  gnuplot*background:  white
  gnuplot*textColor:   black
  gnuplot*borderColor: black
  gnuplot*axisColor:   black
  gnuplot*line1Color:  red
  gnuplot*line2Color:  green
  gnuplot*line3Color:  blue
  gnuplot*line4Color:  magenta
  gnuplot*line5Color:  cyan
  gnuplot*line6Color:  sienna
  gnuplot*line7Color:  orange
  gnuplot*line8Color:  coral

The command-line syntax for these is simple only for background,
 which maps directly to the usual X11 toolkit option "-bg".  All
 others can only be set on the command line by use of the generic
 "-xrm" resource override option

Examples:

gnuplot -background coral
 to change the background color.

gnuplot -xrm 'gnuplot*line1Color:blue'
 to override the first linetype color.

?commands set terminal x11 grayscale_resources
?set terminal x11 grayscale_resources
?set term x11 grayscale_resources
?x11 grayscale_resources
?grayscale_resources
 When `-gray` is selected, `gnuplot` honors the following resources for
 grayscale or color displays (shown here with their default values).  Note
 that the default background is black.
  gnuplot*background: black
  gnuplot*textGray:   white
  gnuplot*borderGray: gray50
  gnuplot*axisGray:   gray50
  gnuplot*line1Gray:  gray100
  gnuplot*line2Gray:  gray60
  gnuplot*line3Gray:  gray80
  gnuplot*line4Gray:  gray40
  gnuplot*line5Gray:  gray90
  gnuplot*line6Gray:  gray50
  gnuplot*line7Gray:  gray70
  gnuplot*line8Gray:  gray30

?set terminal x11 line_resources
?set term x11 line_resources
?x11 line_resources
 NB: THIS SECTION IS LARGELY IRRELEVANT IN GNUPLOT VERSION 5
 `gnuplot` honors the following resources for setting the width (in pixels) of
 plot lines (shown here with their default values.)  0 or 1 means a minimal
 width line of 1 pixel width.  A value of 2 or 3 may improve the appearance of
 some plots.
  gnuplot*borderWidth: 1
  gnuplot*axisWidth:   0
  gnuplot*line1Width:  0
  gnuplot*line2Width:  0
  gnuplot*line3Width:  0
  gnuplot*line4Width:  0
  gnuplot*line5Width:  0
  gnuplot*line6Width:  0
  gnuplot*line7Width:  0
  gnuplot*line8Width:  0

`gnuplot` honors the following resources for setting the dash style used for
 plotting lines.  0 means a solid line.  A two-digit number `jk` (`j` and `k`
 are >= 1 and <= 9) means a dashed line with a repeated pattern of `j` pixels
 on followed by `k` pixels off.  For example, '16' is a dotted line with one
 pixel on followed by six pixels off.  More elaborate on/off patterns can be
 specified with a four-digit value.  For example, '4441' is four on, four off,
 four on, one off.  The default values shown below are for monochrome displays
 or monochrome rendering on color or grayscale displays.
 Color displays default to dashed:off 
  gnuplot*dashed:       off
  gnuplot*borderDashes:   0
  gnuplot*axisDashes:    16
  gnuplot*line1Dashes:    0
  gnuplot*line2Dashes:   42
  gnuplot*line3Dashes:   13
  gnuplot*line4Dashes:   44
  gnuplot*line5Dashes:   15
  gnuplot*line6Dashes: 4441
  gnuplot*line7Dashes:   42
  gnuplot*line8Dashes:   13

?set terminal x11 pm3d_resources
?set term x11 pm3d_resources
?x11 pm3d_resources
?x11 pm3d
 NB: THIS SECTION IS LARGELY IRRELEVANT IN GNUPLOT VERSION 5
 Choosing the appropriate visual class and number of colors is a crucial
 point in X11 applications and a bit awkward, since X11 supports six visual
 types in different depths.

By default `gnuplot` uses the default visual of the screen. The number of
 colors which can be allocated depends on the visual class chosen. On a
 visual class with a depth > 12bit, gnuplot starts with a maximal number
 of 0x200 colors.  On a visual class with a depth > 8bit (but <= 12 bit)
 the maximal number of colors is 0x100, on <= 8bit displays the maximum
 number of colors is 240 (16 are left for line colors).

Gnuplot first starts to allocate the maximal number of colors as stated
 above.  If this fails, the number of colors is reduced by the factor 2
 until gnuplot gets all colors which are requested. If dividing `maxcolors`
 by 2 repeatedly results in a number which is smaller than `mincolors`
 `gnuplot` tries to install a private colormap. In this case the window
 manager is responsible for swapping colormaps when the pointer is moved
 in and out the x11 driver's window.

The default for `mincolors` is maxcolors / (num_colormaps > 1 ? 2 : 8),
 where num_colormaps is the number of colormaps which are currently used
 by gnuplot (usually 1, if only one x11 window is open).

Some systems support multiple (different) visual classes together on one
 screen. On these systems it might be necessary to force gnuplot to use a
 specific visual class, e.g. the default visual might be 8bit PseudoColor
 but the screen would also support 24bit TrueColor which would be the
 preferred choice.

The information about an Xserver's capabilities can be obtained with the
 program `xdpyinfo`.  For the visual names below you can choose one of
 StaticGray, GrayScale, StaticColor, PseudoColor, TrueColor, DirectColor.
 If an Xserver supports a requested visual type at different depths,
 `gnuplot` chooses the visual class with the highest depth (deepest).
 If the requested visual class matches the default visual and multiple
 classes of this type are supported, the default visual is preferred.

Example: on an 8bit PseudoColor visual you can force a private color map
 by specifying `gnuplot*maxcolors: 240` and `gnuplot*mincolors: 240`.

gnuplot*maxcolors:  <integer>
  gnuplot*mincolors:  <integer>
  gnuplot*visual:     <visual name>

?commands set terminal x11 other_resources
?set terminal x11 other_resources
?set term x11 other_resources
?x11 other_resources
 By default the contents of the current plot window are exported to the X11
 clipboard in response to X events in the window. Setting the resource
 'gnuplot*exportselection' to 'off' or 'false' will disable this.

By default text rotation is done using a method that is fast, but can
 corrupt nearby colors depending on the background.  If this is a problem,
 you can set the resource 'gnuplot.fastrotate' to 'off'

gnuplot*exportselection:  off
  gnuplot*fastrotate:  on
  gnuplot*ctrlq:  off
?commands set terminal xlib
?set terminal xlib
?set term xlib
?terminal xlib
?term xlib
?xlib
 The `xlib` terminal driver supports the X11 Windows System.  It generates
 gnuplot_x11 commands, but sends them to the output file specified by
 `set output '<filename>'`. `set term x11` is equivalent to
 `set output "|gnuplot_x11 -noevents"; set term xlib`.
 `xlib` takes the same set of options as `x11`.
?commands set terminal canvas
?set terminal canvas
?set term canvas
?terminal canvas
?term canvas

The `canvas` terminal creates a set of javascript commands that draw onto the
 HTML5 canvas element.
 Syntax:
       set terminal canvas {size <xsize>, <ysize>} {background <rgb_color>}
                           {font {<fontname>}{,<fontsize>}} | {fsize <fontsize>}
                           {{no}enhanced} {linewidth <lw>}
                           {rounded | butt | square}
                           {dashlength <dl>}
                           {standalone {mousing} | name '<funcname>'}
                           {jsdir 'URL/for/javascripts'}
                           {title '<some string>'}

where <xsize> and <ysize> set the size of the plot area in pixels.
 The default size in standalone mode is 600 by 400 pixels.
 The default font size is 10.

NB: Only one font is available, the ascii portion of Hershey simplex Roman
 provided in the file canvastext.js. You can replace this with the file
 canvasmath.js, which contains also UTF-8 encoded Hershey simplex Greek and
 math symbols. For consistency with other terminals, it is also possible to
 use `font "name,size"`. Currently the font `name` is ignored, but browser
 support for named fonts is likely to arrive eventually.

The default `standalone` mode creates an html page containing javascript
 code that renders the plot using the HTML 5 canvas element.  The html page
 links to two required javascript files 'canvastext.js' and 'gnuplot_common.js'.
 An additional file 'gnuplot_dashedlines.js' is needed to support dashed lines.
 By default these point to local files, on unix-like systems usually in
 directory /usr/local/share/gnuplot/<version>/js.  See installation notes for
 other platforms. You can change this by using the `jsdir` option to specify
 either a different local directory or a general URL.  The latter is usually
 appropriate if the plot is exported for viewing on remote client machines.

All plots produced by the canvas terminal are mouseable.  The additional
 keyword `mousing` causes the `standalone` mode to add a mouse-tracking box
 underneath the plot. It also adds a link to a javascript file
 'gnuplot_mouse.js' and to a stylesheet for the mouse box 'gnuplot_mouse.css'
 in the same local or URL directory as 'canvastext.js'.

The `name` option creates a file containing only javascript. Both the
 javascript function it contains and the id of the canvas element that it
 draws onto are taken from the following string parameter.  The commands
       set term canvas name 'fishplot'
       set output 'fishplot.js'
 will create a file containing a javascript function fishplot() that will
 draw onto a canvas with id=fishplot.  An html page that invokes this
 javascript function must also load the canvastext.js function as described
 above.  A minimal html file to wrap the fishplot created above might be:

<html>
       <head>
           <script src="canvastext.js"></script>
           <script src="gnuplot_common.js"></script>
       </head>
       <body onload="fishplot();">
           <script src="fishplot.js"></script>
           <canvas id="fishplot" width=600 height=400>
               <div id="err_msg">No support for HTML 5 canvas element</div>
           </canvas>
       </body>
       </html>

The individual plots drawn on this canvas will have names fishplot_plot_1,
 fishplot_plot_2, and so on. These can be referenced by external javascript
 routines, for example gnuplot.toggle_visibility("fishplot_plot_2").

?commands set terminal cgm
?set terminal cgm
?set term cgm
?terminal cgm
?term cgm
?cgm
 The `cgm` terminal generates a Computer Graphics Metafile, Version 1. 
 This file format is a subset of the ANSI X3.122-1986 standard entitled
 "Computer Graphics - Metafile for the Storage and Transfer of Picture
 Description Information".

Syntax:
       set terminal cgm {color | monochrome} {solid | dashed} {{no}rotate}
                        {<mode>} {width <plot_width>} {linewidth <line_width>}
                        {font "<fontname>,<fontsize>"}
                        {background <rgb_color>}
   [deprecated]         {<color0> <color1> <color2> ...}

`solid` draws all curves with solid lines, overriding any dashed patterns;
 <mode> is `landscape`, `portrait`, or `default`;
 <plot_width> is the assumed width of the plot in points; 
 <line_width> is the line width in points (default 1); 
 <fontname> is the name of a font (see list of fonts below)
 <fontsize> is the size of the font in points (default 12).

The first six options can be in any order.  Selecting `default` sets all
 options to their default values.

The mechanism of setting line colors in the `set term` command is
 deprecated.  Instead you should set the background using a separate
 keyword and set the line colors using `set linetype`.
 The deprecated mechanism accepted colors of the form 'xrrggbb', where x is
 the literal character 'x' and 'rrggbb' are the red, green and blue components
 in hex. The first color was used for the background, subsequent colors are
 assigned to successive line types.

Examples:
       set terminal cgm landscape color rotate dashed width 432 \
                      linewidth 1  'Helvetica Bold' 12       # defaults
       set terminal cgm linewidth 2  14  # wider lines & larger font
       set terminal cgm portrait "Times Italic" 12
       set terminal cgm color solid      # no pesky dashes!
?commands set terminal cgm font
?set terminal cgm font
?set term cgm font
?cgm font
 The first part of a Computer Graphics Metafile, the metafile description,
 includes a font table.  In the picture body, a font is designated by an
 index into this table.  By default, this terminal generates a table with
 the following 35 fonts, plus six more with `italic` replaced by
 `oblique`, or vice-versa (since at least the Microsoft Office and Corel
 Draw CGM import filters treat `italic` and `oblique` as equivalent):

Helvetica
       Helvetica Bold
       Helvetica Oblique
       Helvetica Bold Oblique
       Times Roman
       Times Bold
       Times Italic
       Times Bold Italic
       Courier
       Courier Bold
       Courier Oblique
       Courier Bold Oblique
       Symbol
       Hershey/Cartographic_Roman
       Hershey/Cartographic_Greek
       Hershey/Simplex_Roman
       Hershey/Simplex_Greek
       Hershey/Simplex_Script
       Hershey/Complex_Roman
       Hershey/Complex_Greek
       Hershey/Complex_Script
       Hershey/Complex_Italic
       Hershey/Complex_Cyrillic
       Hershey/Duplex_Roman
       Hershey/Triplex_Roman
       Hershey/Triplex_Italic
       Hershey/Gothic_German
       Hershey/Gothic_English
       Hershey/Gothic_Italian
       Hershey/Symbol_Set_1
       Hershey/Symbol_Set_2
       Hershey/Symbol_Math
       ZapfDingbats
       Script
       15

The first thirteen of these fonts are required for WebCGM.  The
 Microsoft Office CGM import filter implements the 13 standard fonts
 listed above, and also 'ZapfDingbats' and 'Script'.  However, the
 script font may only be accessed under the name '15'.  For more on
 Microsoft import filter font substitutions, check its help file which
 you may find here:
   C:\Program Files\Microsoft Office\Office\Cgmimp32.hlp
 and/or its configuration file, which you may find here:
   C:\Program Files\Common Files\Microsoft Shared\Grphflt\Cgmimp32.cfg

In the `set term` command, you may specify a font name which does not
 appear in the default font table.  In that case, a new font table is
 constructed with the specified font as its first entry. You must ensure
 that the spelling, capitalization, and spacing of the name are
 appropriate for the application that will read the CGM file.  (Gnuplot
 and any MIL-D-28003A compliant application ignore case in font names.)
 If you need to add several new fonts, use several `set term` commands.

Example:
       set terminal cgm 'Old English'
       set terminal cgm 'Tengwar'
       set terminal cgm 'Arabic'
       set output 'myfile.cgm'
       plot ...
       set output

You cannot introduce a new font in a `set label` command.
?commands set terminal cgm fontsize
?set terminal cgm fontsize
?set term cgm fontsize
?cgm fontsize
 Fonts are scaled assuming the page is 6 inches wide.  If the `size`
 command is used to change the aspect ratio of the page or the CGM file
 is converted to a different width, the resulting font sizes will be
 scaled up or down accordingly.  To change the assumed width, use the
 `width` option.
?commands set terminal cgm linewidth
?set terminal cgm linewidth
?set term cgm linewidth
?cgm linewidth
 The `linewidth` option sets the width of lines in pt.  The default width
 is 1 pt.  Scaling is affected by the actual width of the page, as
 discussed under the `fontsize` and `width` options.
?commands set terminal cgm rotate
?set terminal cgm rotate
?set term cgm rotate
?cgm rotate
 The `norotate` option may be used to disable text rotation.  For
 example, the CGM input filter for Word for Windows 6.0c can accept
 rotated text, but the DRAW editor within Word cannot.  If you edit a
 graph (for example, to label a curve), all rotated text is restored to
 horizontal.  The Y axis label will then extend beyond the clip boundary.
 With `norotate`, the Y axis label starts in a less attractive location,
 but the page can be edited without damage.  The `rotate` option confirms
 the default behavior.
?set terminal cgm solid
?set term cgm solid
?cgm solid
 The `solid` option may be used to disable dashed line styles in the
 plots.  This is useful when color is enabled and the dashing of the
 lines detracts from the appearance of the plot. The `dashed` option
 confirms the default behavior, which gives a different dash pattern to
 each line type.
?commands set terminal cgm size
?set terminal cgm size
?set term cgm size
?cgm size
 Default size of a CGM plot is 32599 units wide and 23457 units high for
 landscape, or 23457 units wide by 32599 units high for portrait.
?commands set terminal cgm width
?set terminal cgm width
?set term cgm width
?cgm width
 All distances in the CGM file are in abstract units.  The application
 that reads the file determines the size of the final plot.  By default,
 the width of the final plot is assumed to be 6 inches (15.24 cm).  This
 distance is used to calculate the correct font size, and may be changed
 with the `width` option.  The keyword should be followed by the width in
 points.  (Here, a point is 1/72 inch, as in PostScript.  This unit is
 known as a "big point" in TeX.)  Gnuplot `expressions` can be used to
 convert from other units.

Example:
       set terminal cgm width 432            # default
       set terminal cgm width 6*72           # same as above
       set terminal cgm width 10/2.54*72     # 10 cm wide
?commands set terminal cgm nofontlist
?set terminal cgm nofontlist
?set term cgm nofontlist
?cgm nofontlist
?set terminal cgm winword6
?set term cgm winword6
?cgm winword6
 The default font table includes the fonts recommended for WebCGM, which
 are compatible with the Computer Graphics Metafile input filter for
 Microsoft Office and Corel Draw.  Another application might use
 different fonts and/or different font names, which may not be
 documented.  The `nofontlist` (synonym `winword6`) option deletes the font
 table from the CGM file.  In this case, the reading application should
 use a default table.  Gnuplot will still use its own default font table
 to select font indices.  Thus, 'Helvetica' will give you an index of 1,
 which should get you the first entry in your application's default font
 table. 'Helvetica Bold' will give you its second entry, etc.

?commands set terminal dumb
?set terminal dumb
?set term dumb
?terminal dumb
?term dumb
?dumb
 The `dumb` terminal driver plots into a text block using ascii characters.
 It has an optional size specification and a trailing linefeed flag.

Syntax:
       set terminal dumb {size <xchars>,<ychars>} {[no]feed}
                         {aspect <htic>{,<vtic>}}
                         {[no]enhanced}
                         {mono|ansi|ansi256|ansirgb}

where <xchars> and <ychars> set the size of the text block. The default is
 79 by 24. The last newline is printed only if `feed` is enabled.

The `aspect` option can be used to control the aspect ratio of the plot by
 setting the length of the horizontal and vertical tic marks. Only integer
 values are allowed. Default is 2,1 -- corresponding to the aspect ratio of
 common screen fonts.

The `ansi`, `ansi256`, and `ansirgb` options will include escape
 sequences in the output to handle colors.  Note that these might
 not be handled by your terminal.  Default is `mono`.
 To obtain the best color match in `ansi` mode, you should use
 `set colorsequence classic`.
 Depending on the mode, the `dumb` terminal will emit the
 following sequences (without the additional whitespace):

ESC [ 0 m           reset attributes to defaults
       foreground color:
       ESC [ 1 m           set intense/bold
       ESC [ 22 m          intense/bold off
       ESC [ <fg> m        with color code 30 <= <fg> <= 37
       ESC [ 39 m          reset to default
       ESC [ 38; 5; <c> m  with palette index 16 <= <c> <= 255
       ESC [ 38; 2; <r>; <g>; <b> m  with components 0 <= <r,g,b> <= 255
       background color:
       ESC [ <bg> m        with color code 40 <= <bg> <= 47
       ESC [ 49 m          reset to default
       ESC [ 48; 5; <c> m  with palette index 16 <= <c> <= 231
       ESC [ 48; 2; <r>; <g>; <b> m  with components 0 <= <r,g,b> <= 255

See also e.g. the description at
           https://en.wikipedia.org/wiki/ANSI_escape_code#Colors

Example:
       set term dumb mono size 60,15 aspect 1
       set tics nomirror scale 0.5
       plot [-5:6.5] sin(x) with impulse ls -1

1 +-------------------------------------------------+
         0.8 +|||++                   ++||||++                 |
         0.6 +|||||+                 ++|||||||+  sin(x) +----+ |
         0.4 +||||||+               ++|||||||||+               |
         0.2 +|||||||+             ++|||||||||||+             +|
           0 ++++++++++++++++++++++++++++++++++++++++++++++++++|
        -0.2 +        +|||||||||||+              +|||||||||||+ |
        -0.4 +         +|||||||||+                +|||||||||+  |
        -0.6 +          +|||||||+                  +|||||||+   |
        -0.8 +           ++||||+                    ++||||+    |
          -1 +---+--------+--------+-------+--------+--------+-+
                -4       -2        0       2        4        6  
?commands set terminal dxf
?set terminal dxf
?set term dxf
?terminal dxf
?term dxf
?dxf
 Terminal driver `dxf` for export to  AutoCad (Release 10.x).
 It has no options. The default size is 120x80 AutoCad units.
 `dxf` uses seven colors (white, red, yellow, green, cyan, blue and magenta)
 that can be changed only by modifying the source file.  If a black-and-white
 plotting device is used the colors are mapped to differing line thicknesses.
 Note: someone please update this terminal to the 2012 DXF standard!
?commands set terminal emf
?set terminal emf
?set term emf
?terminal emf
?term emf
?emf
 The `emf` terminal generates an Enhanced Metafile Format file.
 This file format is recognized by many Windows applications.

Syntax:
       set terminal emf {color | monochrome}
                        {enhanced {noproportional}}
                        {rounded | butt}
                        {linewidth <LW>} {dashlength <DL>}
                        {size XX,YY} {background <rgb_color>}
                        {font "<fontname>{,<fontsize>}"}
                        {fontscale <scale>}

In `monochrome` mode successive line types cycle through dash patterns.
 `linewidth <factor>` multiplies all line widths by this factor.
 `dashlength <factor>` is useful for thick lines.
 <fontname> is the name of a font; and 
 `<fontsize>` is the size of the font in points.

The nominal size of the output image defaults to 1024x768 in arbitrary
 units. You may specify a different nominal size using the `size` option.

Enhanced text mode tries to approximate proportional character spacing.
 If you are using a monospaced font, or don't like the approximation, you
 can turn off this correction using the `noproportional` option.

The default settings are `color font "Arial,12" size 1024,768`
 Selecting `default` sets all options to their default values.

Examples:
       set terminal emf 'Times Roman Italic, 12'
?commands set terminal fig
?set terminal fig
?set term fig
?terminal fig
?term fig
?fig
?xfig
 The `fig` terminal device generates output in the Fig graphics language
 for import into the xfig interactive drawing tool.
 Notes: 
       The fig terminal was significantly revised in gnuplot version 5.3.
       Currently only version 3.2 of the fig file format is supported.
       Use of dash patterns may require Xfig 3.2.6 or newer.

Syntax:
       set terminal fig {monochrome | color}
                        {small | big | size <xsize>{in|cm},<ysize>{in|cm}}
                        {landscape | portrait}
                        {font "<fontname>{,<fontsize>}"} {fontsize <size>}
                        {textnormal | {textspecial texthidden textrigid}}
                        {{linewidth|lw} <multiplier>}

The default settings are
       set term fig color small landscape font "Times Roman,10" lw 1.0

`size` sets the size of the drawing area to <xsize>*<ysize> in units of
 inches (default) or centimeters. The default is `size 5in,3in`.
 `small` is shorthand for `size 5in,3in` (3in,5in in portrait mode).
 `big` is shorthand for `size 8in,5in`.

`font` sets the text font face to <fontname> and its size to <fontsize>
 points. Choice is limited to the 35 standard PostScript fonts.
 `textnormal` resets the text flags and selects postscript fonts,
 `textspecial` sets the text flags for LaTeX specials,
 `texthidden` sets the hidden flag and `textrigid` the rigid flag.

`linewidth` is a multiplier for the linewidth property of all lines.

Additional point-plot symbols are also available in the `fig` driver. The
 symbols can be used through `pointtype` values % 100 above 50, with different
 fill intensities controlled by <pointtype> % 5 and outlines in black (for
 <pointtype> % 10 < 5) or in the current color.  Available symbols are
         50 - 59:  circles
         60 - 69:  squares
         70 - 79:  diamonds
         80 - 89:  upwards triangles
         90 - 99:  downwards triangles
 The size of these symbols scales with the font size.

RGB colors will be replaced with gray unless they have been defined in a
 linetype prior to plotting or match a known named color or palette value.
 See `colornames`.
 E.g.
       set linetype 999 lc rgb '#aabbcc'
       plot $data with fillecurve fillcolor rgb '#aabbcc'

?commands set terminal hpgl
?set terminal hpgl
?set term hpgl
?terminal hpgl
?term hpgl
?hpgl
 The `hpgl` driver produces HPGL output for devices like the HP7475A plotter.
 There are two options which can be set: the number of pens and `eject`,
 which tells the plotter to eject a page when done.  The default is to use 6
 pens and not to eject the page when done.

The international character sets ISO-8859-1 and CP850 are recognized via
 `set encoding iso_8859_1` or `set encoding cp850` (see `set encoding` for
 details).

Syntax:
       set terminal hpgl {<number_of_pens>} {eject}

The selection

set terminal hpgl 8 eject

is equivalent to the previous `hp7550` terminal, and the selection

set terminal hpgl 4

is equivalent to the previous `hp7580b` terminal.
 HPGL graphics can be imported by many software packages.
?commands set terminal pcl5
?set terminal pcl5
?set term pcl5
?terminal pcl5
?term pcl5
?pcl5
 The `pcl5` driver supports PCL5e/PCL5c printers.  It (mostly) uses the HP-GL/2 vector format.

Syntax:
       set terminal pcl5 {<mode>} {{no}enhanced}
           {size <plotsize> | size <width>{unit},<height>{unit}}
           {font "<fontname>,<size>"} {pspoints | nopspoints}
           {fontscale <scale>} {pointsize <scale>} {linewidth <scale}
           {rounded|butt} {color <number_of_pens>}

<mode> is `landscape` or `portrait`. <plotsize> is the physical
 plotting size of the plot, which can be one of the following formats: `letter`
 for standard (8 1/2" X 11") displays, `legal` for (8 1/2" X 14") displays,
 `noextended` for (36" X 48") displays (a letter size ratio),
 `extended` for (36" X 55") displays (almost a legal size ratio), or
 `a4` for (296mm X 210mm) displays.  You can also explicitly specify the canvas
 size using the `width` and `height` options. Default unit is `in`.
 Default size is `letter`.

<fontname> can be one of stick, univers (default), albertus, antique_olive,
 arial, avant_garde_gothic, bookman, zapf_chancery, clarendon, coronet, courier
 courier_ps, cg_times, garamond_antigua, helvetica, helvetica_narrow,
 letter_gothic, marigold, new_century_schlbk, cg_omega, palatino, times_new_roman,
 times_roman, zapf_dingbats, truetype_symbols, or wingdings.  Font names are
 case-insensitive and underscores may be replaced by spaces or dashes or may be
 left out.  <fontsize> is the font size in points.

The point type selection can be the a limited default set by specifying
 `nopspoints`, or the same set of point types as provided by the postscript terminal
 by specifying `pspoints` (default).

The `butt` option selects lines with butt ends and mitered joins (default), whereas `rounded` selects rounded line ends and joins.

Line widths, and point and font sizes can be scaled using the `linewidth`, `pointscale`, or `fontscale` options, respectively.
 `color` selects the number of pens <number_of_pens> used in plots.
 Default is 8, minimum 2.

Note that built-in support of some of these options is printer device
 dependent. For instance, all the fonts are supposedly supported by the HP
 Laserjet IV, but only a few (e.g. univers, stick) may be supported by the HP
 Laserjet III and the Designjet 750C. Also, color obviously won't work on
 monochrome devices, but newer ones will do grey-scale.

Defaults: landscape, a4, 8 pens, univers, 12 point, pspoints, butt, no scaling

The `pcl5` terminal will try to request fonts which match your `encoding`.
 Note that this has highest priority, so you might end up with a different
 font face.  The terminal's default `encoding` is `HP Roman-8`.

Limitations:

This terminal does not support alpha transparency. Transparent filling is
 emulated using shading patterns. Boxed text is not implemented.

The support for UTF-8 is limited.  Lacking the label mode for UTF-8 output
 in HP-GL/2, the driver reverts to PCL for strings containing 8bit characters.
 UTF-8 text is limited to angles of 0, 90, 180, and 270 degrees. Also vertical alignment might be off depending on the font.

Some enhanced text features (phantom box, overprinting) require using PCL
 features in addition to HP-GL/2. This conforms to the specs but may not
 work with your printer or software.
?commands set terminal hp500c
?set terminal hp500c
?set term hp500c
?terminal hp500c
?term hp500c
?hp500c
 Note: only available if gnuplot is configured --with-bitmap-terminals.
 The `hp500c` terminal driver supports the Hewlett Packard HP DeskJet 500c.
 It has options for resolution and compression.

Syntax:
       set terminal hp500c {<res>} {<comp>}

where `res` can be 75, 100, 150 or 300 dots per inch and `comp` can be "rle",
 or "tiff".  Any other inputs are replaced by the defaults, which are 75 dpi
 and no compression.  Rasterization at the higher resolutions may require a
 large amount of memory.
?commands set terminal hpljii
?set terminal hpljii
?set term hpljii
?terminal hpljii
?term hpljii
?hpljii
?commands set terminal hpdj
?set terminal hpdj
?set term hpdj
?terminal hpdj
?term hpdj
?hpdj
 Note: only available if gnuplot is configured --with-bitmap-terminals.
 The `hpljii` terminal driver supports the HP Laserjet Series II printer.  The
 `hpdj` driver supports the HP DeskJet 500 printer.  These drivers allow a
 choice of resolutions.

Syntax:
       set terminal hpljii | hpdj {<res>}

where `res` may be 75, 100, 150 or 300 dots per inch; the default is 75.
 Rasterization at the higher resolutions may require a large amount of memory.

The `hp500c` terminal is similar to `hpdj`; `hp500c` additionally supports
 color and compression.
?commands set terminal hppj
?set terminal hppj
?set term hppj
?terminal hppj
?term hppj
?hppj
 Note: only available if gnuplot is configured --with-bitmap-terminals.
 The `hppj` terminal driver supports the HP PaintJet and HP3630 printers.  The
 only option is the choice of font.

Syntax:
       set terminal hppj {FNT5X9 | FNT9X17 | FNT13X25}

with the middle-sized font (FNT9X17) being the default.
?commands set terminal png
?set terminal png
?set term png
?terminal png
?term png
?png
 Syntax:
       set terminal png 
              {{no}enhanced}
              {{no}transparent} {{no}interlace}
              {{no}truecolor} {rounded|butt}
              {linewidth <lw>} {dashlength <dl>}
              {tiny | small | medium | large | giant}
              {font "<face> {,<pointsize>}"} {fontscale <scale>}
              {size <x>,<y>} {{no}crop}
              {background <rgb_color>}

PNG, JPEG and GIF images are created using the external library libgd.
 PNG plots may be viewed interactively by piping the output to the
 'display' program from the ImageMagick package as follows:
                set term png
                set output '| display png:-'
 You can view the output from successive plot commands interactively by typing
 <space> in the display window.  To save the current plot to a file,
 left click in the display window and choose `save`.

`transparent` instructs the driver to make the background color transparent.
 Default is `notransparent`.

`interlace` instructs the driver to generate interlaced PNGs.
 Default is `nointerlace`.

The `linewidth` and `dashlength` options are scaling factors that affect all
 lines drawn, i.e. they are multiplied by values requested in various drawing
 commands.

By default output png images use 256 indexed colors. The `truecolor` option
 instead creates TrueColor images with 24 bits of color information per pixel.
 Transparent fill styles require the `truecolor` option. See `fillstyle`.
 A transparent background is possible in either indexed or TrueColor images.

`butt` instructs the driver to use a line drawing method that does
 not overshoot the desired end point of a line.  This setting is only
 applicable for line widths greater than 1.  This setting is most useful when
 drawing horizontal or vertical lines.  Default is `rounded`.

The details of font selection are complicated.
 Two equivalent simple examples are given below:
      set term png font arial 11
      set term png font "arial,11"
 For more information please see the separate section under `fonts`.

?set term png examples
       set terminal png medium size 640,480 background '#ffffff'

Use the medium size built-in non-scaleable, non-rotatable font.
 Use white (24-bit RGB in hexadecimal) for the non-transparent background.

set terminal png font arial 14 size 800,600

Searches for a scalable font with face name 'arial' and sets the font
 size to 14pt.  Please see `fonts` for details of how the font search
 is done.

set terminal png transparent truecolor enhanced

Use 24 bits of color information per pixel, with a transparent background.
 Use the `enhanced text` mode to control the layout of strings to be printed.

?commands set terminal jpeg
?set terminal jpeg
?set term jpeg
?terminal jpeg
?term jpeg
?jpeg
 Syntax:
       set terminal jpeg 
              {{no}enhanced}
              {{no}interlace}
              {linewidth <lw>} {dashlength <dl>} {rounded|butt}
              {tiny | small | medium | large | giant}
              {font "<face> {,<pointsize>}"} {fontscale <scale>}
              {size <x>,<y>} {{no}crop}
              {background <rgb_color>}

PNG, JPEG and GIF images are created using the external library libgd.
 In most cases, PNG is to be preferred for single plots, and GIF for
 animations.  Both are loss-less image formats, and produce better image
 quality than the lossy JPEG format. This is in particular noticeable
 for solid color lines against a solid background, i.e. exactly the sort
 of image typically created by gnuplot.

The `interlace` option creates a progressive JPEG image.
 Default is `nointerlace`.

The `linewidth` and `dashlength` options are scaling factors that affect all
 lines drawn, i.e. they are multiplied by values requested in various drawing
 commands.

The details of font selection are complicated.
 Two equivalent simple examples are given below:
      set term jpeg font arial 11
      set term jpeg font "arial,11"
 For more information please see the separate section under `fonts`.

?commands set terminal gif
?set terminal gif
?set term gif
?terminal gif
?term gif
?gif
 Syntax:
       set terminal gif 
              {{no}enhanced}
              {{no}transparent} {rounded|butt}
              {linewidth <lw>} {dashlength <dl>}
              {tiny | small | medium | large | giant}
              {font "<face> {,<pointsize>}"} {fontscale <scale>}
              {size <x>,<y>} {{no}crop}
              {background <rgb_color>}
              {animate {delay <d>} {loop <n>} {optimize}}

PNG, JPEG and GIF images are created using the external library libgd.
 GIF plots may be viewed interactively by piping the output to the
 'display' program from the ImageMagick package as follows:
                set term gif
                set output '| display gif:-'
 You can view the output from successive plot commands interactively by typing
 <space> in the display window.  To save the current plot to a file,
 left click in the display window and choose `save`.

`transparent` instructs the driver to make the background color transparent.
 Default is `notransparent`.

The `linewidth` and `dashlength` options are scaling factors that affect all
 lines drawn, i.e. they are multiplied by values requested in various drawing
 commands.

?set term gif animate
?animation
?animate

set term gif animate {delay <d>} {loop <n>} {{no}optimize}}

The gif terminal `animate` option creates a single gif file containing
 multiple frames. The delay between display of successive frames may be
 specified in units of 1/100 second (default 5), but this value may or may
 not be honored accurately by a program used to view the animation later.
 The number of animation loops during playback can be specified, with the
 default of 0 meaning unlimited looping. Again this value may or may not be
 honored by the program later used for viewing.
 An animation sequence is terminated by the next `set output` or `set term`
 command.

The `optimize` option [DEPRECATED] is passed to the gd library when the
 output file is opened. It has two effects on the animation.

1) A single color map is used for the entire animation. This requires
 that all colors used in any frame of the animation are already
 defined in the first frame.

2) If possible, only the portions of a frame that differ from the
 previous frame are stored in the animation file.  This space saving
 may not be possible if the animation uses transparency.

Both of these optimizations are intended to produce a smaller output file,
 but the decrease in size is probably only significant for long animations.
 Caveat: The implementation of optimization in libgd is known to be buggy.
 Therefore use of this option in gnuplot is not recommended.

Example showing continuous rotation:
      set term gif animate loop 0
      set output 'rotating_surface.gif'
      do for [ang=1:359] {
          set view 60, ang
          splot f(x,y) with pm3d
      }
      unset output

?set term gif fonts

The details of font selection are complicated.
 For more information please see the separate section under `fonts gd`.

Examples:

set terminal gif medium noenhanced size 640,480 background '#ffffff'

Use the medium size built-in non-scaleable, non-rotatable font.
 Enhanced text mode will not work with this font.
 Use white (24 bit RGB in hexadecimal) for the non-transparent background.

set terminal gif font arial 14

Searches for a font with face name 'arial' and sets the font size to 14pt.

?commands set terminal sixelgd
?set terminal sixelgd
?set term sixelgd
?terminal sixelgd
?term sixelgd
?sixelgd
 Syntax:
       set terminal sixelgd
              {{no}enhanced} {{no}truecolor}
              {{no}transparent} {rounded|butt}
              {linewidth <lw>} {dashlength <dl>}
              {tiny | small | medium | large | giant}
              {font "<face> {,<pointsize>}"} {fontscale <scale>}
              {size <x>,<y>} {{no}crop} {animate}
              {background <rgb_color>}

The `sixel` output format was originally used by DEC terminals and printers.
 This driver produces a sixel output stream by converting a PNG image created
 internally using the gd library. The sixel output stream can be viewed in the
 terminal as it is created or it can be written to a file so that it can be
 replayed later by echoing the file to the terminal.

The `animate` option resets the cursor position to the terminal top left at
 the start of every plot so that successive plots overwrite the same area on
 the screen rather than having earlier plots scroll off the top. This may be
 desirable in order to create an in-place animation.

`transparent` instructs the driver to make the background color transparent.
 Default is `notransparent`.

The `linewidth` and `dashlength` options are scaling factors that affect all
 lines drawn, i.e. they are multiplied by values requested in various drawing
 commands.

By default the sixel output uses 16 indexed colors. The `truecolor` option
 instead creates a TrueColor png image that is mapped down onto 256 colors
 in the output sixel image. Transparent fill styles require the `truecolor`
 option. See `fillstyle`.
 A `transparent` background is possible in either indexed or TrueColor images.

The details of font selection are complicated.
 For more information please see `fonts`.

The output plot size <x,y> is given in pixels---it defaults to 640x480.
 Please see additional information under `canvas` and `set size`.
 Blank space at the edges of the finished plot may be trimmed using the `crop`
 option, resulting in a smaller final image size. Default is `nocrop`.
 The terminal has been successfully tested with the xterm, mlterm and mintty
 terminals.  The later two support the `truecolor` mode using 256 sixel
 colors out of box. Distributed copies of xterm may or may not have been
 configured to support sixel graphics and may be limited to 16 colors.

?commands set terminal epslatex
?set terminal epslatex
?set term epslatex
?terminal epslatex
?term epslatex
?epslatex
 The `epslatex` driver generates output for further processing by LaTeX.

Syntax:
       set terminal epslatex   {default}
       set terminal epslatex   {standalone | input}
                               {oldstyle | newstyle}
                               {level1 | leveldefault | level3}
                               {color | colour | monochrome}
                               {background <rgbcolor> | nobackground}
                               {dashlength | dl <DL>}
                               {linewidth | lw <LW>} {pointscale | ps <PS>}
                               {rounded | butt}
                               {clip | noclip}
                               {palfuncparam <samples>{,<maxdeviation>}}
                               {size <XX>{unit},<YY>{unit}}
                               {header <header> | noheader}
                               {blacktext | colortext | colourtext}
                               {{font} "fontname{,fontsize}" {<fontsize>}}
                               {fontscale <scale>}

The epslatex terminal prints a plot as `terminal postscript eps`
 but transfers the texts to LaTeX instead of including in the PostScript
 code. Thus, many options are the same as in the `postscript terminal`.

The appearance of the epslatex terminal changed between versions 4.0 and 4.2
 to reach better consistency with the postscript terminal:
 The plot size has been changed from 5 x 3 inches to 5 x 3.5 inches;
 the character width is now estimated to be 60% of the font size
 while the old epslatex terminal used 50%;  now, the larger number of
 postscript linetypes and symbols are used.  To reach an appearance that is
 nearly identical to the old one specify the option `oldstyle`. (In fact
 some small differences remain: the symbol sizes are slightly different, the
 tics are half as large as in the old terminal which can be changed using
 `set tics scale`, and the arrows have all features as in the postscript
 terminal.)

If you see the error message
       "Can't find PostScript prologue file ... "
 Please see and follow the instructions in `postscript prologue`.

The option `color` enables color, while `monochrome` prefers black and white
 drawing elements. Further, `monochrome` uses gray `palette` but it does not
 change color of objects specified with an explicit `colorspec`.
 `dashlength` or `dl` scales the length of dashed-line segments by <DL>,
 which is a floating-point number greater than zero.
 `linewidth` or `lw` scales all linewidths by <LW>.

By default the generated PostScript code uses language features that were
 introduced in PostScript Level 2, notably filters and pattern-fill of
 irregular objects such as filledcurves.  PostScript Level 2 features are
 conditionally protected so that PostScript Level 1 interpreters do not issue
 errors but, rather, display a message or a PostScript Level 1 approximation.
 The `level1` option substitutes PostScript Level 1 approximations of these
 features and uses no PostScript Level 2 code.  This may be required by some
 old printers and old versions of Adobe Illustrator.  The flag `level1` can be
 toggled later by editing a single line in the PostScript output file to force
 PostScript Level 1 interpretation.  In the case of files containing level 2
 code, the above features will not appear or will be replaced by a note when
 this flag is set or when the interpreting program does not indicate that it
 understands level 2 PostScript or higher. The flag `level3` enables PNG
 encoding for bitmapped images, which can reduce the output size considerably.

`rounded` sets line caps and line joins to be rounded; `butt` is the
 default, butt caps and mitered joins.

`clip` tells PostScript to clip all output to the bounding box;
 `noclip` is the default.

`palfuncparam` controls how `set palette functions` are encoded as gradients
 in the output. Analytic color component functions (set via
 `set palette functions`) are encoded as linear interpolated gradients in the
 postscript output:  The color component functions are sampled at <samples>
 points and all points are removed from this gradient which can be removed
 without changing the resulting colors by more than <maxdeviation>. For
 almost every useful palette you may safely leave the defaults of
 <samples>=2000 and <maxdeviation>=0.003 untouched.

The default size for postscript output is 10 inches x 7 inches. The default
 for eps output is 5 x 3.5 inches.  The `size` option changes this to
 whatever the user requests. By default the X and Y sizes are taken to be in
 inches, but other units are possibly (currently only cm). The BoundingBox
 of the plot is correctly adjusted to contain the resized image.
 Screen coordinates always run from 0.0 to 1.0 along the full length of the
 plot edges as specified by the `size` option.
 NB: `this is a change from the previously recommended method of using the
 set size command prior to setting the terminal type`.  The old method left
 the BoundingBox unchanged and screen coordinates did not correspond to the
 actual limits of the plot.

`blacktext` forces all text to be written in black even in color mode;

The epslatex driver offers a special way of controlling text positioning:
 (a) If any text string begins with '{', you also need to include a '}' at the
 end of the text, and the whole text will be centered both horizontally
 and vertically by LaTeX.  (b) If the text string begins with '[', you need
 to continue it with: a position specification (up to two out of t,b,l,r,c),
 ']{', the text itself, and finally, '}'. The text itself may be anything
 LaTeX can typeset as an LR-box. \rule{}{}'s may help for best positioning.
 See also the documentation for the `pslatex` terminal driver.
 To create multiline labels, use \shortstack, for example
    set ylabel '[r]{\shortstack{first line \\ second line}}'

The `back` option of `set label` commands is handled slightly different
 than in other terminals. Labels using 'back' are printed behind all other
 elements of the plot while labels using 'front' are printed above 
 everything else.

The driver produces two different files, one for the eps part of the figure
 and one for the LaTeX part. The name of the LaTeX file is taken from the
 `set output` command. The name of the eps file is derived by replacing
 the file extension (normally `.tex`) with `.eps` instead.  There is no
 LaTeX output if no output file is given!  Remember to close the
 `output file` before next plot unless in `multiplot` mode.

In your LaTeX documents use '\input{filename}' to include the figure.
 The `.eps` file is included by the command \includegraphics{...}, so you
 must also include \usepackage{graphicx} in the LaTeX preamble.  If you
 want to use coloured text (option `textcolour`) you also have to include
 \usepackage{color} in the LaTeX preamble.

Pdf files can be made from the eps file using 'epstopdf'. If the graphics
 package is properly configured, the LaTeX files can also be processed by
 pdflatex without changes, using the pdf files instead of the eps files.
 The behaviour concerning font selection depends on the header mode.
 In all cases, the given font size is used for the calculation of proper
 spacing. When not using the `standalone` mode the actual LaTeX font and
 font size at the point of inclusion is taken, so use LaTeX commands for
 changing fonts. If you use e.g. 12pt as font size for your LaTeX
 document, use '"" 12' as options. The font name is ignored. If using
 `standalone` the given font and font size are used, see below for a
 detailed description.

If text is printed coloured is controlled by the TeX booleans \ifGPcolor
 and \ifGPblacktext. Only if \ifGPcolor is true and \ifGPblacktext is
 false, text is printed coloured. You may either change them in the
 generated TeX file or provide them globally in your TeX file, for example
 by using
    \newif\ifGPblacktext
    \GPblacktexttrue
 in the preamble of your document. The local assignment is only done if no
 global value is given.

When using the epslatex terminal give the name of the TeX file in the
 `set output` command including the file extension (normally ".tex").
 The eps filename is generated by replacing the extension by ".eps".

If using the `standalone` mode a complete LaTeX header is added to the
 LaTeX file; and "-inc" is added to the filename of the eps file.
 The `standalone` mode generates a TeX file that produces
 output with the correct size when using dvips, pdfTeX, or VTeX.
 The default, `input`, generates a file that has to be included into a
 LaTeX document using the \input command.

If a font other than "" or "default" is given it is interpreted as
 LaTeX font name.  It contains up to three parts, separated by a comma:
 'fontname,fontseries,fontshape'.  If the default fontshape or fontseries
 are requested, they can be omitted.  Thus, the real syntax for the fontname
 is '[fontname][,fontseries][,fontshape]'.  The naming convention for all
 parts is given by the LaTeX font scheme.  The fontname is 3 to 4 characters
 long and is built as follows: One character for the font vendor, two
 characters for the name of the font, and optionally one additional
 character for special fonts, e.g., 'j' for fonts with old-style numerals
 or 'x' for expert fonts. The names of many fonts is described in
           http://www.tug.org/fontname/fontname.pdf
 For example, 'cmr' stands for Computer Modern Roman, 'ptm' for Times-Roman,
 and 'phv' for Helvetica.  The font series denotes the thickness of the
 glyphs, in most cases 'm' for normal ("medium") and 'bx' or 'b' for bold
 fonts.  The font shape is 'n' for upright, 'it' for italics, 'sl' for
 slanted, or 'sc' for small caps, in general.  Some fonts may provide
 different font series or shapes.

Examples:

Use Times-Roman boldface (with the same shape as in the surrounding text):
       set terminal epslatex 'ptm,bx'
 Use Helvetica, boldface, italics:
       set terminal epslatex 'phv,bx,it'
 Continue to use the surrounding font in slanted shape:
       set terminal epslatex ',,sl'
 Use small capitals:
       set terminal epslatex ',,sc'

By this method, only text fonts are changed. If you also want to change
 the math fonts you have to use the "gnuplot.cfg" file or the `header`
 option, described below.

In standalone mode, the font size is taken from the given font size in the
 `set terminal` command. To be able to use a specified font size, a file
 "size<size>.clo" has to reside in the LaTeX search path.  By default,
 10pt, 11pt, and 12pt are supported.  If the package "extsizes" is
 installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.

The `header` option takes a string as argument.  This string is written
 into the generated LaTeX file.  If using the `standalone` mode, it is 
 written into the preamble, directly before the \begin{document} command.
 In the `input` mode, it is placed directly after the \begingroup command
 to ensure that all settings are local to the plot.

Examples:

Use T1 fontencoding, change the text and math font to Times-Roman as well
 as the sans-serif font to Helvetica:
     set terminal epslatex standalone header \
     "\\usepackage[T1]{fontenc}\n\\usepackage{mathptmx}\n\\usepackage{helvet}"
 Use a boldface font in the plot, not influencing the text outside the plot:
     set terminal epslatex input header "\\bfseries"

If the file "gnuplot.cfg" is found by LaTeX it is input in the preamble
 the LaTeX document, when using `standalone` mode.  It can be used for
 further settings, e.g., changing the document font to Times-Roman,
 Helvetica, and Courier, including math fonts (handled by "mathptmx.sty"):
       \usepackage{mathptmx}
       \usepackage[scaled=0.92]{helvet}
       \usepackage{courier}
 The file "gnuplot.cfg" is loaded before the header information given
 by the `header` command.  Thus, you can use `header` to overwrite some of
 settings performed using "gnuplot.cfg"

?commands set terminal pslatex
?set terminal pslatex
?set term pslatex
?terminal pslatex
?term pslatex
?pslatex
?commands set terminal pstex
?set terminal pstex
?set term pstex
?terminal pstex
?term pstex
?pstex
 The `pslatex` driver generates output for further processing by LaTeX,
 while the `pstex` driver generates output for further processing by
 TeX. `pslatex` uses \specials understandable by dvips and xdvi. Figures
 generated by `pstex` can be included in any plain-based format (including
 LaTeX).

Syntax:
       set terminal [pslatex | pstex] {default}
       set terminal [pslatex | pstex]
                               {rotate | norotate}
                               {oldstyle | newstyle}
                               {auxfile | noauxfile}
                               {level1 | leveldefault | level3}
                               {color | colour | monochrome}
                               {background <rgbcolor> | nobackground}
                               {dashlength | dl <DL>}
                               {linewidth | lw <LW>} {pointscale | ps <PS>}
                               {rounded | butt}
                               {clip | noclip}
                               {palfuncparam <samples>{,<maxdeviation>}}
                               {size <XX>{unit},<YY>{unit}}
                               {<font_size>}

If you see the error message
       "Can't find PostScript prologue file ... "
 Please see and follow the instructions in `postscript prologue`.

`rounded` sets line caps and line joins to be rounded; `butt` is the
 default, butt caps and mitered joins.

`clip` tells PostScript to clip all output to the bounding box;
 `noclip` is the default.

if `rotate` is specified, the y-axis label is rotated.
 <font_size> is the size (in pts) of the desired font.

If `auxfile` is specified, it directs the driver to put the PostScript
 commands into an auxiliary file instead of directly into the LaTeX file.
 This is useful if your pictures are large enough that dvips cannot handle
 them.  The name of the auxiliary PostScript file is derived from the name of
 the TeX file given on the `set output` command; it is determined by replacing
 the trailing `.tex` (actually just the final extent in the file name) with
 `.ps` in the output file name, or, if the TeX file has no extension, `.ps`
 is appended.  The `.ps` is included into the `.tex` file by a
 \special{psfile=...} command.  Remember to close the `output file` before
 next plot unless in `multiplot` mode.

Gnuplot versions prior to version 4.2 generated plots of the size
 5 x 3 inches using the ps(la)tex terminal while the current version generates
 5 x 3.5 inches to be consistent with the postscript eps terminal.  In
 addition, the character width is now estimated to be 60% of the font size
 while the old epslatex terminal used 50%. To reach the old format specify
 the option `oldstyle`.

The pslatex driver offers a special way of controlling text positioning: 
 (a) If any text string begins with '{', you also need to include a '}' at the
 end of the text, and the whole text will be centered both horizontally
 and vertically by LaTeX.  (b) If the text string begins with '[', you need
 to continue it with: a position specification (up to two out of t,b,l,r),
 ']{', the text itself, and finally, '}'. The text itself may be anything
 LaTeX can typeset as an LR-box. \rule{}{}'s may help for best positioning.

The options not described here are identical to the `Postscript terminal`.
 Look there if you want to know what they do.

Examples:
       set term pslatex monochrome rotate       # set to defaults
 To write the PostScript commands into the file "foo.ps":
       set term pslatex auxfile
       set output "foo.tex"; plot ...; set output
 About label positioning:
 Use gnuplot defaults (mostly sensible, but sometimes not really best):
        set title '\LaTeX\ -- $ \gamma $'
 Force centering both horizontally and vertically:
        set label '{\LaTeX\ -- $ \gamma $}' at 0,0
 Specify own positioning (top here):
        set xlabel '[t]{\LaTeX\ -- $ \gamma $}'
 The other label -- account for long ticlabels:
        set ylabel '[r]{\LaTeX\ -- $ \gamma $\rule{7mm}{0pt}}'

Linewidths and pointsizes may be changed with `set style line`.
?commands set terminal postscript
?set terminal postscript
?set term postscript
?terminal postscript
?term postscript
?postscript
 Several options may be set in the `postscript` driver.

Syntax:
       set terminal postscript {default}
       set terminal postscript {landscape | portrait | eps}
                               {enhanced | noenhanced}
                               {defaultplex | simplex | duplex}
                               {fontfile {add | delete} "<filename>"
                                | nofontfiles} {{no}adobeglyphnames}
                               {level1 | leveldefault | level3}
                               {color | colour | monochrome}
                               {background <rgbcolor> | nobackground}
                               {dashlength | dl <DL>}
                               {linewidth | lw <LW>} {pointscale | ps <PS>}
                               {rounded | butt}
                               {clip | noclip}
                               {palfuncparam <samples>{,<maxdeviation>}}
                               {size <XX>{unit},<YY>{unit}}
                               {blacktext | colortext | colourtext}
                               {{font} "fontname{,fontsize}" {<fontsize>}}
                               {fontscale <scale>}
 If you see the error message
       "Can't find PostScript prologue file ... "
 Please see and follow the instructions in `postscript prologue`.

`landscape` and `portrait` choose the plot orientation.
 `eps` mode generates EPS (Encapsulated PostScript) output, which is just
 regular PostScript with some additional lines that allow the file to be
 imported into a variety of other applications.  (The added lines are
 PostScript comment lines, so the file may still be printed by itself.)  To
 get EPS output, use the `eps` mode and make only one plot per file.  In `eps`
 mode the whole plot, including the fonts, is reduced to half of the default
 size.

`enhanced` enables enhanced text mode features (subscripts,
 superscripts and mixed fonts). See `enhanced` for more information.
 `blacktext` forces all text to be written in black even in color mode;

Duplexing in PostScript is the ability of the printer to print on both
 sides of the same sheet of paper.  With `defaultplex`, the default setting
 of the printer is used; with `simplex` only one side is printed; `duplex`
 prints on both sides (ignored if your printer can't do it).

`"<fontname>"` is the name of a valid PostScript font; and `<fontsize>` is
 the size of the font in PostScript points.
 In addition to the standard postscript fonts, an oblique version of the
 Symbol font, useful for mathematics, is defined. It is called
 "Symbol-Oblique".

`default` sets all options to their defaults: `landscape`, `monochrome`,
 `dl 1.0`, `lw 1.0`, `defaultplex`, `enhanced`, "Helvetica" and
 14pt.  Default size of a PostScript plot is 10 inches wide and 7 inches high.
 The option `color` enables color, while `monochrome` prefers black and white
 drawing elements. Further, `monochrome` uses gray `palette` but it does not
 change color of objects specified with an explicit `colorspec`.
 `dashlength` or `dl` scales the length of dashed-line segments by <DL>,
 which is a floating-point number greater than zero.
 `linewidth` or `lw` scales all linewidths by <LW>.

`rounded` sets line caps and line joins to be rounded; `butt` is the
 default, butt caps and mitered joins.

`clip` tells PostScript to clip all output to the bounding box;
 `noclip` is the default.

Fonts listed by `fontfile` or `fontfile add` encapsulate the font
 definitions of the listed font from a postscript Type 1 or TrueType font
 file directly into the gnuplot output postscript file.  Thus, the enclosed
 font can be used in labels, titles, etc.  See the section
 `postscript fontfile` for more details.  With `fontfile delete`, a fontfile
 is deleted from the list of embedded files.  `nofontfiles` cleans the list
 of embedded fonts.

Examples:
       set terminal postscript default       # old postscript
       set terminal postscript enhanced      # old enhpost
       set terminal postscript landscape 22  # old psbig
       set terminal postscript eps 14        # old epsf1
       set terminal postscript eps 22        # old epsf2
       set size 0.7,1.4; set term post portrait color "Times-Roman" 14
       set term post "VAGRoundedBT_Regular" 14 fontfile "bvrr8a.pfa"

Linewidths and pointsizes may be changed with `set style line`.

The `postscript` driver supports about 70 distinct pointtypes, selectable
 through the `pointtype` option on `plot` and `set style line`.

Several possibly useful files about `gnuplot`'s PostScript are included
 in the /docs/psdoc subdirectory of the `gnuplot` distribution and at the
 distribution sites.  These are "ps_symbols.gpi" (a `gnuplot` command file
 that, when executed, creates the file "ps_symbols.ps" which shows all the
 symbols available through the `postscript` terminal), "ps_guide.ps" (a
 PostScript file that contains a summary of the enhanced syntax and a page
 showing what the octal codes produce with text and symbol fonts),
 "ps_file.doc" (a text file that contains a discussion of the organization
 of a PostScript file written by `gnuplot`), and "ps_fontfile_doc.tex"
 (a LaTeX file which contains a short documentation concerning the
 encapsulation of LaTeX fonts with a glyph table of the math fonts).

A PostScript file is editable, so once `gnuplot` has created one, you are
 free to modify it to your heart's desire.  See the `editing postscript`
 section for some hints.
?commands set terminal postscript editing
?set terminal postscript editing
?set term postscript editing
?terminal postscript editing
?term postscript editing
?editing_postscript
?editing postscript
 The PostScript language is a very complex language---far too complex to
 describe in any detail in this document.  Nevertheless there are some things
 in a PostScript file written by `gnuplot` that can be changed without risk of
 introducing fatal errors into the file.

For example, the PostScript statement "/Color true def" (written into the
 file in response to the command `set terminal postscript color`), may be
 altered in an obvious way to generate a black-and-white version of a plot.
 Similarly line colors, text colors, line weights and symbol sizes can also be
 altered in straight-forward ways.  Text (titles and labels) can be edited to
 correct misspellings or to change fonts.  Anything can be repositioned, and
 of course anything can be added or deleted, but modifications such as these
 may require deeper knowledge of the PostScript language.

The organization of a PostScript file written by `gnuplot` is discussed in
 the text file "ps_file.doc" in the docs/ps subdirectory of the gnuplot
 source distribution.
?commands set terminal postscript fontfile
?set terminal postscript fontfile
?set term postscript fontfile
?terminal postscript fontfile
?term postscript fontfile
?postscript fontfile
?fontfile
       set term postscript ... fontfile {add|delete} <filename>
 The `fontfile` or `fontfile add` option takes one file name as argument
 and encapsulates this file into the postscript output in order to make
 this font available for text elements (labels, tic marks, titles, etc.).
 The `fontfile delete` option also takes one file name as argument. It
 deletes this file name from the list of encapsulated files.

The postscript terminal understands some
 font file formats: Type 1 fonts in ASCII file format (extension ".pfa"),
 Type 1 fonts in binary file format (extension ".pfb"), and TrueType
 fonts (extension ".ttf"). pfa files are understood directly, pfb and ttf
 files are converted on the fly if appropriate conversion tools are
 installed (see below). You have to specify the full filename including the
 extension. Each `fontfile` option takes exact one font file name. This
 option can be used multiple times in order to include more than one font
 file.

The search order used to find font files is
 (1) absolute pathname or current working directory
 (2) any of the directories specified by `set loadpath`
 (3) the directory specified by `set fontpath`
 (4) the directory given in environmental variable GNUPLOT_FONTPATH.
 NB: This is a CHANGE from earlier versions of gnuplot.

For using the encapsulated font file you have to specify the font name
 (which normally is not the same as the file name). When embedding a
 font file by using the `fontfile` option in interactive mode, the 
 font name is printed on the screen. E.g.
    Font file 'p052004l.pfb' contains the font 'URWPalladioL-Bold'. Location:
    /usr/lib/X11/fonts/URW/p052004l.pfb

When using pfa or pfb fonts, you can also find it out by looking into the
 font file. There is a line similar to "/FontName /URWPalladioL-Bold def".
 The middle string without the slash is the fontname, here
 "URWPalladioL-Bold".
 For TrueType fonts, this is not so easy since the font name is stored in a
 binary format. In addition, they often have spaces in the font names which
 is not supported by Type 1 fonts (in which a TrueType is converted on the
 fly). The font names are changed in order to eliminate the spaces in the
 fontnames. The easiest way to find out which font name is generated for
 use with gnuplot, start gnuplot in interactive mode and type in
 "set terminal postscript fontfile '<filename.ttf>'".

For converting font files (either ttf or pfb) to pfa format, the conversion
 tool has to read the font from a file and write it to standard output. If
 the output cannot be written to standard output, on-the-fly conversion is
 not possible.

For pfb files "pfbtops" is a tool which can do this. If this program
 is installed on your system the on the fly conversion should work.
 Just try to encapsulate a pfb file. If the compiled in program call does
 not work correctly you can specify how this program is called by
 defining the environment variable GNUPLOT_PFBTOPFA e.g. to
 "pfbtops %s". The `%s` will be replaced by the font file name and thus
 has to exist in the string.

If you don't want to do the conversion on the fly but get a pfa file of
 the font you can use the tool "pfb2pfa" which is written in simple c
 and should compile with any c compiler.
 It is available from many ftp servers, e.g.
           ftp://ftp.dante.de/tex-archive/fonts/utilities/ps2mf/
 In fact, "pfbtopfa" and "pfb2ps" do the same job. "pfbtopfa" puts
 the resulting pfa code into a file, whereas "pfbtops" writes it to
 standard output.

TrueType fonts are converted into Type 1 pfa format, e.g.
 by using the tool "ttf2pt1" which is available from
           http://ttf2pt1.sourceforge.net/
 If the builtin conversion does not
 work, the conversion command can be changed by the environment variable
 GNUPLOT_TTFTOPFA. For usage with ttf2pt1 it may be set to
 "ttf2pt1 -a -e -W 0 %s - ". Here again, `%s` stands for the
 file name.

For special purposes you also can use a pipe (if available for your
 operating system). Therefore you start the file name definition with 
 the character "<" and append a program call. This program has 
 to write pfa data to standard output. Thus, a pfa file may be accessed
 by `set fontfile "< cat garamond.pfa"`.

For example, including Type 1 font files can be used for including the
 postscript output in LaTeX documents. The "european computer modern"
 font (which is a variant of the "computer modern" font) is available
 in pfb format from any CTAN server, e.g.
           ftp://ftp.dante.de/tex-archive/fonts/ps-type1/cm-super/
 For example, the file "sfrm1000.pfb" contains the normal upright fonts
 with serifs in the design size 10pt (font name "SFRM1000").
 The computer modern fonts, which are still necessary for mathematics,
 are available from
           ftp://ftp.dante.de/tex-archive/fonts/cm/ps-type1/bluesky
 With these you can use any character available in TeX. However, the
 computer modern fonts have a strange encoding. (This is why you should not
 use cmr10.pfb for text, but sfrm1000.pfb instead.)
 The usage of TeX fonts is shown in one of the demos.
 The file "ps_fontfile_doc.tex" in the /docs/psdoc subdirectory of the
 `gnuplot` source distribution contains a table with glyphs of the TeX
 mathfonts.

If the font "CMEX10" is embedded (file "cmex10.pfb") gnuplot defines
 the additional font "CMEX10-Baseline". It is shifted vertically in order
 to fit better to the other glyphs (CMEX10 has its baseline at the top of
 the symbols).
?commands set terminal postscript prologue
?set terminal postscript prologue
?terminal postscript prologue
?postscript prologue
?prologue
 Each PostScript output file includes a %%Prolog section and possibly some
 additional user-defined sections containing, for example, character encodings.
 These sections are copied from a set of PostScript prologue files that are
 either compiled into the gnuplot executable or stored elsewhere on your
 computer. A default directory where these files live is set at the time
 gnuplot is built. However, you can override this default either by using the
 gnuplot command `set psdir` or by defining an environment variable
 GNUPLOT_PS_DIR. See `set psdir`.
?commands set terminal postscript adobeglyphnames
?set terminal postscript adobeglyphnames
?terminal postscript adobeglyphnames
?postscript adobeglyphnames
?adobeglyphnames
 This setting is only relevant to PostScript output with UTF-8 encoding.
 It controls the names used to describe characters with Unicode entry points
 higher than 0x00FF.  That is, all characters outside of the Latin1 set.
 In general unicode characters do not have a unique name; they have only a
 unicode identification code.  However, Adobe have a recommended scheme for
 assigning names to certain ranges of characters (extended Latin, Greek, etc).
 Some fonts use this scheme, others do not.  By default, gnuplot will use
 the Adobe glyph names.  E.g. the lower case Greek letter alpha will be called
 /alpha.  If you specific `noadobeglyphnames` then instead gnuplot will use
 /uni03B1 to describe this character.  If you get this setting wrong, the
 character may not be found even if it is present in the font.
 It is probably always correct to use the default for Adobe fonts, but for
 other fonts you may have to try both settings.  See also `fontfile`.

?commands set terminal svg
?set terminal svg
?set term svg
?terminal svg
?term svg
?svg
 This terminal produces files in the W3C Scalable Vector Graphics format.

Syntax:
       set terminal svg {size <x>,<y> {|fixed|dynamic}}
                        {mouse} {standalone | jsdir <dirname>}
                        {name <plotname>}
                        {font "<fontname>{,<fontsize>}"} {{no}enhanced}
                        {fontscale <multiplier>}
                        {rounded|butt|square} {solid|dashed} {linewidth <lw>}
                        {background <rgb_color>}

where <x> and <y> are the size of the SVG plot to generate,
 `dynamic` allows a svg-viewer to resize plot, whereas the default
 setting, `fixed`, will request an absolute size.

`linewidth <w>` increases the width of all lines used in the figure
 by a factor of <w>.

<font> is the name of the default font to use (default Arial) and
 <fontsize> is the font size (in points, default 12). SVG viewing
 programs may substitute other fonts when the file is displayed.

The enhanced text mode syntax is shared with other gnuplot terminal types.
 See `enhanced` for more details.

The `mouse` option tells gnuplot to add support for mouse tracking and for
 toggling individual plots on/off by clicking on the corresponding key entry.
 By default this is done by including a link that points to a script in a
 local directory, usually /usr/local/share/gnuplot/<version>/js.
 You can change this by using the `jsdir` option to specify either a
 different local directory or a general URL. The latter is usually
 appropriate if you are embedding the svg into a web page.
 Alternatively, the `standalone` option embeds the mousing code in the svg
 document itself rather than linking to an external resource.

When an SVG file will be used in conjunction with external files,
 e.g. if it is referenced by javascript code in a web page or parent document,
 then a unique name is required to avoid potential conflicting references
 to other SVG plots.  Use the `name` option to ensure uniqueness.

?set terminal domterm
?terminal domterm
?set term domterm
?term domterm
?domterm
 The `domterm` terminal device runs on the DomTerm terminal emulator
 including the domterm and qtdomterm programs.
 It supports SVG graphics embedded directly in the terminal output.
 See http://domterm.org .

Please read the help for the `svg` terminal.

?commands set terminal tkcanvas
?set terminal tkcanvas
?set term tkcanvas
?terminal tkcanvas
?term tkcanvas
?tkcanvas
 This terminal driver generates Tk canvas widget commands in one of the
 following scripting languages: Tcl (default), Perl, Python, Ruby, or REXX.

Syntax:
       set terminal tkcanvas {tcl | perl | perltkx | python | ruby | rexx}
                             {standalone | input}
                             {interactive}
                             {rounded | butt}
                             {nobackground | background <rgb color>}
                             {{no}rottext}
                             {size <width>,<height>}
                             {{no}enhanced}
                             {externalimages | pixels}

Execute the following sequence of Tcl/Tk commands to display the result:

package require Tk
       # the following two lines are only required to support external images
       package require img::png
       source resize.tcl
       source plot.tcl
       canvas .c -width 800 -height 600
       pack .c
       gnuplot .c

Or, for Perl/Tk use a program like this:

use Tk;
       my $top = MainWindow->new;
       my $c = $top->Canvas(-width => 800, -height => 600)->pack;
       my $gnuplot = do "plot.pl";
       $gnuplot->($c);
       MainLoop;

Or, for Perl/Tkx use a program like this:

use Tkx;
       my $top = Tkx::widget->new(".");
       my $c = $top->new_tk__canvas(-width => 800, -height => 600);
       $c->g_pack;
       my $gnuplot = do "plot.pl";
       $gnuplot->($c);
       Tkx::MainLoop();

Or, for Python/Tkinter use a program like this:

from tkinter import *
       from tkinter import font
       root = Tk()
       c = Canvas(root, width=800, height=600)
       c.pack()
       exec(open('plot.py').read())
       gnuplot(c)
       root.mainloop()

Or, for Ruby/Tk use a program like this:

require 'tk'
       root = TkRoot.new { title 'Ruby/Tk' }
       c = TkCanvas.new(root, 'width'=>800, 'height'=>600) { pack  { } }
       load('plot.rb')
       gnuplot(c)
       Tk.mainloop

Or, for Rexx/Tk use a program like this:

/**/
       call RxFuncAdd 'TkLoadFuncs', 'rexxtk', 'TkLoadFuncs'
       call TkLoadFuncs
       cv = TkCanvas('.c', '-width', 800, '-height', 600)
       call TkPack cv
       call 'plot.rex' cv
       do forever
           cmd = TkWait()
           if cmd = 'AWinClose' then leave
           interpret 'call' cmd
       end

The code generated by `gnuplot` (in the above examples, this code is
 written to "plot.<ext>") contains the following procedures:

gnuplot(canvas)
    takes the name of a canvas as its argument.
    When called, it clears the canvas, finds the size of the canvas and
    draws the plot in it, scaled to fit.

gnuplot_plotarea()
    returns a list containing the borders of the plotting area
    (xleft, xright, ytop, ybot) in canvas screen coordinates.    It works only for 2-dimensional plotting (`plot`).

gnuplot_axisranges()
    returns the ranges of the two axes in plot coordinates
    (x1min, x1max, y1min, y1max, x2min, x2max, y2min, y2max).
    It works only for 2-dimensional plotting (`plot`).

You can create self-contained, minimal scripts using the `standalone`
 option.  The default is `input` which creates scripts which have to be
 source'd (or loaded or called or whatever the adequate term is for the
 language selected).

If the `interactive` option is specified, mouse clicking on a line segment
 will print the coordinates of its midpoint to stdout.
 The user can supersede this behavior by supplying a procedure
 user_gnuplot_coordinates which takes the following arguments:
   win id x1s y1s x2s y2s x1e y1e x2e y2e x1m y1m x2m y2m,
 i.e. the name of the canvas and the id of the line segment followed by the
 coordinates of its start and end point in the two possible axis ranges; the
 coordinates of the midpoint are only filled for logarithmic axes.

By default the canvas is `transparent`, but an explicit background color
 can be set with the `background` option.

`rounded` sets line caps and line joins to be rounded;
 `butt` is the default:  butt caps and mitered joins.

Text at arbitrary angles can be activated with the `rottext` option,
 which requires Tcl/Tk 8.6 or later. The default is `norottext`.

The `size` option tries to optimize the tic and font sizes for the given
 canvas size.  By default an output size of 800 x 600 pixels is assumed.

`enhanced` selects `enhanced text` processing (default), but is currently
 only available for Tcl.

The `pixels` (default) option selects the failsafe pixel-by-pixel image
 handler, see also `image pixels`.
 The `externalimages` option saves images as external png images, which
 are later loaded and scaled by the tkcanvas code.  This option is only
 available for Tcl and display may be slow in some situations since the
 Tk image handler does not provide arbitrary scaling.  Scripts need to source
 the provided rescale.tcl.

Interactive mode is not yet implemented for Python/Tk and Rexx/Tk.
 Interactive mode for Ruby/Tk does not yet support user_gnuplot_coordinates.
?commands set terminal pbm
?set terminal pbm
?set term pbm
?terminal pbm
?term pbm
?pbm
 Note: only available if gnuplot is configured --with-bitmap-terminals.
 Syntax:
       set terminal pbm {<fontsize>} {<mode>} {size <x>,<y>}

where <fontsize> is `small`, `medium`, or `large` and <mode> is `monochrome`,
 `gray` or `color`.  The default plot size is 640 pixels wide and 480 pixels
 high. The output size is white-space padded to the nearest multiple of
 8 pixels on both x and y. This empty space may be cropped later if needed.

The output of the `pbm` driver depends upon <mode>: `monochrome` produces a
 portable bitmap (one bit per pixel), `gray` a portable graymap (three bits
 per pixel) and `color` a portable pixmap (color, four bits per pixel).

The output of this driver can be used with various image conversion and
 manipulation utilities provided by NETPBM.  Based on Jef Poskanzer's
 PBMPLUS package, NETPBM provides programs to convert the above PBM formats
 to GIF, TIFF, MacPaint, Macintosh PICT, PCX, X11 bitmap and many others.
 Complete information is available at http://netpbm.sourceforge.net/.

Examples:
       set terminal pbm small monochrome                # defaults
       set terminal pbm color medium size 800,600
       set output '| pnmrotate 45 | pnmtopng > tilted.png'  # uses NETPBM
?commands set terminal epson_180dpi
?set terminal epson_180dpi
?set term epson_180dpi
?terminal epson_180dpi
?term epson_180dpi
?epson_180dpi
?commands set terminal epson_60dpi
?set terminal epson_60dpi
?set term epson_60dpi
?terminal epson_60dpi
?term epson_60dpi
?epson_60dpi
?commands set terminal epson_lx800
?set terminal epson_lx800
?set term epson_lx800
?terminal epson_lx800
?term epson_lx800
?epson_lx800
?commands set terminal nec_cp6
?set terminal nec_cp6
?set term nec_cp6
?terminal nec_cp6
?term nec_cp6
?nec_cp6
?commands set terminal okidata
?set terminal okidata
?set term okidata
?terminal okidata
?term okidata
?okidata
?commands set terminal starc
?set terminal starc
?set term starc
?terminal starc
?term starc
?starc
?commands set terminal tandy_60dpi
?set terminal tandy_60dpi
?set term tandy_60dpi
?terminal tandy_60dpi
?term tandy_60dpi
?tandy_60dpi
?commands set terminal dpu414
?set terminal dpu414
?set term dpu414
?terminal dpu414
?term dpu414
?dpu414
 Note: only available if gnuplot is configured --with-bitmap-terminals.
 This driver supports a family of Epson printers and derivatives.

`epson_180dpi` and `epson_60dpi` are drivers for Epson LQ-style 24-pin
 printers with resolutions of 180 and 60 dots per inch, respectively.

`epson_lx800` is a generic 9-pin driver appropriate for printers like the
 Epson LX-800, the Star NL-10 and NX-1000, the PROPRINTER, and so forth.

`nec_cp6` is generic 24-pin driver that can be used for printers like the
 NEC CP6 and the Epson LQ-800.

The `okidata` driver supports the 9-pin OKIDATA 320/321 Standard printers.

The `starc` driver is for the Star Color Printer.

The `tandy_60dpi` driver is for the Tandy DMP-130 series of 9-pin, 60-dpi
 printers.

The `dpu414` driver is for the Seiko DPU-414 thermal printer.

`nec_cp6` has the options:

Syntax:
       set terminal nec_cp6 {monochrome | colour | draft}

which defaults to monochrome.

`dpu414` has the options:

Syntax:
       set terminal dpu414 {small | medium | large} {normal | draft}

which defaults to medium (=font size) and normal.
 Preferred combinations are `medium normal` and `small draft`.

?commands set terminal pict2e
?set terminal pict2e
?set term pict2e
?terminal pict2e
?term pict2e
?pict2e
 The `pict2e` terminal uses the LaTeX2e variant of the picture environment.
 It replaces terminals which were based on the original LaTeX picture
 environment: `latex`, `emtex`, `tpic`, and `eepic`. (EXPERIMENTAL)

Alternatives to this terminal with a more complete support of gnuplot's
 features are `tikz`, `pstricks`, `cairolatex`, `pslatex`, `epslatex`
 and `mp`.

Syntax:
       set terminal pict2e
                    {font "{<fontname>}{,<fontsize>}"}
                    {size <XX>{unit}, <YY>{unit}}
                    {color | monochrome}
                    {linewidth <lw>} {rounded | butt}
                    {texarrows | gparrows} {texpoints | gppoints}
                    {smallpoints | tinypoints | normalpoints}

This terminal requires the following standard LaTeX packages: `pict2e`,
 `xcolor`, `graphics`/`graphicx` and `amssymb`. For pdflatex, the
 `transparent` package is used to support transparency.

By default the plot will inherit font settings from the embedding document.
 You have the option to force a font with the `font` option, like cmtt
 (Courier) or cmr (Roman), instead. In this case you may also force a specific
 fontsize. Otherwise the fontsize argument is used to estimate the required
 space for text.
 Unless your driver is capable of building fonts at any size (e.g. dvips),
 stick to the standard 10, 11 and 12 point sizes.

The default size for the plot is 5 inches by 3 inches. The `size` option
 changes this to whatever the user requests. By default the X and Y sizes
 are taken to be in inches, but other units are possible (currently only cm).

With `texpoints`, points are drawn using LaTeX commands like "\Diamond"
 and "\Box".  These are provided by the the latexsym package, which is part
 of the base distribution and thus part of any LaTeX implementation.
 Other point types use symbols from the amssymb package.
 With `gppoints`, the terminal will use gnuplot's internal routines for
 drawing point symbols instead.

With the `texpoints` option, you can select three different point sizes:
 `normalpoints`, `smallpoints`, and `tinypoints`.

`color` causes gnuplot to produce \color{...} commands so that the graphs
 are colored. Using this option, you must include \usepackage{xcolor}
 in the preamble of your LaTeX document. `monochrome` will avoid the use of
 any color commands in the output.
 Transparent color fill is available if pdflatex is used.

`linewidth` sets the scale factor for the width of lines.
 `rounded` sets line caps and line joins to be rounded. `butt` sets butt
 caps and mitered joins and is the default.

`pict2e` only supports dotted lines, but not dashed lines.
 All default line types are solid. Use `set linetype` with the `dashtype`
 property to change.

`texarrows` draws `arrow`s using LaTeX commands which are shorter but do
 not offer all options. `gparrows` selects drawing arrows using gnuplot's own
 routine for full functionality instead.

?commands set terminal pstricks
?set terminal pstricks
?set term pstricks
?terminal pstricks
?term pstricks
?pstricks
 The `pstricks` driver is intended for use with the "pstricks.sty" macro
 package for LaTeX.  It is an alternative to the `eepic` and `latex` drivers.
 You need "pstricks.sty", and, of course, a printer that understands
 PostScript, or a converter such as Ghostscript.

PSTricks is available at
           http://tug.org/PSTricks/.
 This driver definitely does not come close to using the full
 capability of the PSTricks package.

Syntax:
       set terminal pstricks
                      {unit | size <XX>{unit},<YY>{unit}}
                      {standalone | input}
                      {blacktext | colortext | colourtext}
                      {linewidth <lw>} {rounded | butt}
                      {pointscale <ps>}
                      {psarrows | gparrows}
                      {background <rgbcolor>}

The `unit` option produces a plot with internal dimensions 1x1. The default
 is a plot of `size 5in,3in`.

`standalone` produces a LaTeX file with possibly multiple plots, ready
 to be compiled.  The default is `input` to produce a TeX file which can
 be included.

`blacktext` forces all text to be written in black. `colortext` enables
 colored text. The default is `blacktext`.

`rounded` sets line caps and line joins to be rounded. `butt` sets butt
 caps and mitered joins and is the default.

`linewidth` and `pointscale` scale the width of lines and the size of point
 symbols, respectively.

`psarrows` draws `arrow`s using PSTricks commands which are shorter but do
 not offer all options. `gparrows` selects drawing arrows using gnuplot's own
 routine for full functionality instead.

The old `hacktext` option has been replaced by the new default format (%h),
 see `format specifiers`.

Transparency requires support by Ghostscript or conversion to PDF.
?commands set terminal texdraw
?set terminal texdraw
?set term texdraw
?terminal texdraw
?term texdraw
?texdraw
 The `texdraw` terminal driver supports the (La)TeX texdraw environment.  It is
 intended for use with the texdraw package,
 see https://www.ctan.org/tex-archive/graphics/texdraw/ .

set terminal texdraw
                      {size <XX>{unit},<YY>{unit}}
                      {standalone | input}
                      {blacktext | colortext | colourtext}
                      {linewidth <lw>} {rounded | butt}
                      {pointscale <ps>}
                      {psarrows | gparrows} {texpoints | gppoints}
                      {background <rgbcolor>}

Note: Graphics are in grayscale only. Text is always black. Boxes and polygons
 are filled using solid gray levels only. Patterns are not available.

Points, among other things, are drawn using the LaTeX commands "\Diamond" and
 "\Box".  These commands no longer belong to the LaTeX2e core; they are included
 in the latexsym package, which is part of the base distribution and thus part
 of any LaTeX implementation.  Please do not forget to use this package.
 Other point types use symbols from the amssymb package. For compatibility with
 plain TeX you need to specify the `gppoints` option.

`standalone` produces a LaTeX file with possibly multiple plots, ready
 to be compiled.  The default is `input` to produce a TeX file which can
 be included.

`blacktext` forces all text to be written in black. `colortext` enables
 "colored" text. The default is `blacktext` and "color" means grayscale
 really.

`rounded` sets line caps and line joins to be rounded; `butt` sets butt
 caps and mitered joins and is the default.

`linewidth` and `pointscale` scale the width of lines and the size of point
 symbols, respectively. `pointscale`only applies to `gppoints`.

`psarrows` draws `arrow`s using TeXdraw commands which are shorter but do not
 offer all options. `gparrows` selects drawing drawing arrows using gnuplot's
 own routine for full functionality instead.  Similarly, `texpoints`, and 
 `gppoints` select LaTeX symbols or gnuplot's point drawing routines.
?commands set terminal mf
?set terminal mf
?set term mf
?terminal mf
?term mf
?mf
?metafont
 The `mf` terminal driver creates an input file to the METAFONT program.  Thus a
 figure may be used in the TeX document in the same way as is a character.

To use a picture in a document, the METAFONT program must be run with the
 output file from `gnuplot` as input.  Thus, the user needs a basic knowledge
 of the font creating process and the procedure for including a new font in a
 document.  However, if the METAFONT program is set up properly at the local
 site, an unexperienced user could perform the operation without much trouble.

The text support is based on a METAFONT character set.  Currently the
 Computer Modern Roman font set is input, but the user is in principal free to
 choose whatever fonts he or she needs.  The METAFONT source files for the
 chosen font must be available.  Each character is stored in a separate
 picture variable in METAFONT.  These variables may be manipulated (rotated,
 scaled etc.) when characters are needed.  The drawback is the interpretation
 time in the METAFONT program.  On some machines (i.e. PC) the limited amount
 of memory available may also cause problems if too many pictures are stored.

The `mf` terminal has no options.
?commands set terminal mf detailed
?set terminal mf detailed
?set term mf detailed
?mf detailed
?metafont detailed

- Set your terminal to METAFONT:
   set terminal mf
 - Select an output-file, e.g.:
   set output "myfigures.mf"
 - Create your pictures. Each picture will generate a separate character. Its
 default size will be 5*3 inches. You can change the size by saying `set size
 0.5,0.5` or whatever fraction of the default size you want to have.

- Quit `gnuplot`.

- Generate a TFM and GF file by running METAFONT on the output of `gnuplot`.
 Since the picture is quite large (5*3 in), you will have to use a version of
 METAFONT that has a value of at least 150000 for memmax.  On Unix systems
 these are conventionally installed under the name bigmf.  For the following
 assume that the command virmf stands for a big version of METAFONT.  For
 example:

- Invoke METAFONT:
     virmf '&plain'
 - Select the output device: At the METAFONT prompt ('*') type:
     \mode:=CanonCX;     % or whatever printer you use
 - Optionally select a magnification:
     mag:=1;             % or whatever you wish
 - Input the `gnuplot`-file:
     input myfigures.mf
 On a typical Unix machine there will usually be a script called "mf" that
 executes virmf '&plain', so you probably can substitute mf for virmf &plain.
 This will generate two files: mfput.tfm and mfput.$$$gf (where $$$ indicates
 the resolution of your device).  The above can be conveniently achieved by
 typing everything on the command line, e.g.:
 virmf '&plain' '\mode:=CanonCX; mag:=1; input myfigures.mf'
 In this case the output files will be named myfigures.tfm and
 myfigures.300gf.

- Generate a PK file from the GF file using gftopk:
   gftopk myfigures.300gf myfigures.300pk
 The name of the output file for gftopk depends on the DVI driver you use.
 Ask your local TeX administrator about the naming conventions.  Next, either
 install the TFM and PK files in the appropriate directories, or set your
 environment variables properly.  Usually this involves setting TEXFONTS to
 include the current directory and doing the same thing for the environment
 variable that your DVI driver uses (no standard name here...).  This step is
 necessary so that TeX will find the font metric file and your DVI driver will
 find the PK file.

- To include your pictures in your document you have to tell TeX the font:
   \font\gnufigs=myfigures
 Each picture you made is stored in a single character.  The first picture is
 character 0, the second is character 1, and so on...  After doing the above
 step, you can use the pictures just like any other characters.  Therefore, to
 place pictures 1 and 2 centered in your document, all you have to do is:
   \centerline{\gnufigs\char0}
   \centerline{\gnufigs\char1}
 in plain TeX.  For LaTeX you can, of course, use the picture environment and
 place the picture wherever you wish by using the \makebox and \put macros.

This conversion saves you a lot of time once you have generated the font;
 TeX handles the pictures as characters and uses minimal time to place them,
 and the documents you make change more often than the pictures do.  It also
 saves a lot of TeX memory.  One last advantage of using the METAFONT driver
 is that the DVI file really remains device independent, because no \special
 commands are used as in the eepic and tpic drivers.
?commands set terminal mpost
?set terminal mp
?set term mp
?terminal mp
?term mp
?mp
?metapost

The `mp` driver produces output intended to be input to the Metapost program.
 Running Metapost on the file creates EPS files containing the plots. By
 default, Metapost passes all text through TeX.  This has the advantage of
 allowing essentially  any TeX symbols in titles and labels.

Syntax:
    set term mp {color | colour | monochrome}
                {solid | dashed}
                {notex | tex | latex}
                {magnification <magsize>}
                {psnfss | psnfss-version7 | nopsnfss}
                {prologues <value>}
                {a4paper}
                {amstex}
                {"<fontname> {,<fontsize>}"}

The option `color` causes lines to be drawn in color (on a printer or display
 that supports it), `monochrome` (or nothing) selects black lines.  The option
 `solid` draws solid lines, while `dashed` (or nothing) selects lines with
 different patterns of dashes.  If `solid` is selected but `color` is not,
 nearly all lines will be identical.  This may occasionally be useful, so it is
 allowed.

The option `notex` bypasses TeX entirely, therefore no TeX code can be used in
 labels under this option.  This is intended for use on old plot files or files
 that make frequent use of common characters like `$` and `%` that require
 special handling in TeX.

The option `tex` sets the terminal to output its text for TeX to process.

The option `latex` sets the terminal to output its text for processing by
 LaTeX. This allows things like \frac for fractions which LaTeX knows about
 but TeX does not.  Note that you must set the environment variable TEX to the
 name of your LaTeX executable (normally latex) if you use this option or use
 `mpost --tex=<name of LaTeX executable> ...`. Otherwise metapost will try and
 use TeX to process the text and it won't work.

Changing font sizes in TeX has no effect on the size of mathematics, and there
 is no foolproof way to make such a change, except by globally  setting a
 magnification factor. This is the purpose of the `magnification` option. It
 must be followed by a scaling factor. All text (NOT the graphs) will be scaled
 by this factor. Use this if you have math that you want at some size other
 than the default 10pt. Unfortunately, all math will be the same size, but see
 the discussion below on editing the MP output. `mag` will also work under
 `notex` but there seems no point in using it as the font size option (below)
 works as well.

The option `psnfss` uses postscript fonts in combination with LaTeX. Since
 this option only makes sense, if LaTeX is being used, the `latex` option is selected
 automatically. This option includes the following packages for LaTeX:
 inputenc(latin1), fontenc(T1), mathptmx, helvet(scaled=09.2), courier, latexsym 
 and textcomp.

The option `psnfss-version7` uses also postscript fonts in LaTeX (option `latex`
 is also automatically selected), but uses the following packages with LaTeX:
 inputenc(latin1), fontenc(T1), times, mathptmx, helvet and courier.

The option `nopsnfss` is the default and uses the standard font (cmr10 if not
 otherwise specified).

The option `prologues` takes a value as an additional argument and adds the line
 `prologues:=<value>` to the metapost file. If a value of `2` is specified metapost
 uses postscript fonts to generate the eps-file, so that the result can be viewed
 using e.g. ghostscript. Normally the output of metapost uses TeX fonts and therefore
 has to be included in a (La)TeX file before you can look at it.

The option `noprologues` is the default. No additional line specifying the prologue
 will be added.

The option `a4paper` adds a `[a4paper]` to the documentclass. Normally letter paper
 is used (default). Since this option is only used in case of LaTeX, the `latex` option
 is selected automatically.

The option `amstex` automatically selects the `latex` option and includes the following
 LaTeX packages: amsfonts, amsmath(intlimits). By default these packages are not
 included.

A name in quotes selects the font that will be used when no explicit font is
 given in a `set label` or `set title`.  A name recognized by TeX (a TFM file
 exists) must be used.  The default is "cmr10" unless `notex` is selected,
 then it is "pcrr8r" (Courier).  Even under `notex`, a TFM file is needed by
 Metapost. The file `pcrr8r.tfm` is the name given to Courier in LaTeX's psnfss
 package.  If you change the font from the `notex` default, choose a font that
 matches the ASCII encoding at least in the range 32-126.  `cmtt10` almost
 works, but it has a nonblank character in position 32 (space).

The size can be any number between 5.0 and 99.99.  If it is omitted, 10.0 is
 used.  It is advisable to use `magstep` sizes: 10 times an integer or
 half-integer power of 1.2, rounded to two decimals, because those are the most
 available sizes of fonts in TeX systems.

All the options are optional.  If font information is given, it must be at the
 end, with size (if present) last.  The size is needed to select a size for the
 font, even if the font name includes size information.  For example,
 `set term mp "cmtt12"` selects cmtt12 shrunk to the default size 10.  This
 is probably not what you want or you would have used cmtt10.

The following common ascii characters need special treatment in TeX:
    $, &, #, %, _;  |, <, >;  ^, ~,  \, {, and }
 The five characters $, #, &, _, and % can simply be escaped, e.g., `\$`.
 The three characters <, >, and | can be wrapped in math mode, e.g., `$<$`.
 The remainder require some TeX work-arounds.  Any good book on TeX will give
 some guidance.

If you type your labels inside double quotes, backslashes in TeX code need to
 be escaped (doubled). Using single quotes will avoid having to do this, but
 then you cannot use `\n` for line breaks.  As of this writing, version 3.7 of
 gnuplot processes titles given in a `plot` command differently than in other
 places, and backslashes in TeX commands need to be doubled regardless of the
 style of quotes.

Metapost pictures are typically used in TeX documents.  Metapost deals with
 fonts pretty much the same way TeX does, which is different from most other
 document preparation programs.  If the picture is included in a LaTeX document
 using the graphics package, or in a plainTeX document via epsf.tex, and then
 converted to PostScript with dvips (or other dvi-to-ps converter), the text in
 the plot will usually be handled correctly.  However, the text may not appear
 if you send the Metapost output as-is to a PostScript interpreter.

?commands set terminal mp detailed
?set terminal mp detailed
?set term mp detailed
?mp detailed
?metapost detailed

- Set your terminal to Metapost, e.g.:
    set terminal mp mono "cmtt12" 12

- Select an output-file, e.g.:
    set output "figure.mp"

- Create your pictures.  Each plot (or multiplot group) will generate a
 separate Metapost beginfig...endfig group.  Its default size will be 5 by 3
 inches.  You can change the size by saying `set size 0.5,0.5` or whatever
 fraction of the default size you want to have.

- Quit gnuplot.

- Generate EPS files by running Metapost on the output of gnuplot:
    mpost figure.mp  OR  mp figure.mp
 The name of the Metapost program depends on the system, typically `mpost` for
 a Unix machine and `mp` on many others.  Metapost will generate one EPS file
 for each picture.

- To include your pictures in your document you can use the graphics package
 in LaTeX or epsf.tex in plainTeX:
    \usepackage{graphics} % LaTeX
    \input epsf.tex       % plainTeX
 If you use a driver other than dvips for converting TeX DVI output to PS, you
 may need to add the following line in your LaTeX document:
    \DeclareGraphicsRule{*}{eps}{*}{}
 Each picture you made is in a separate file.  The first picture is in, e.g.,
 figure.0, the second in figure.1, and so on....  To place the third picture in
 your document, for example, all you have to do is:
    \includegraphics{figure.2} % LaTeX
    \epsfbox{figure.2}         % plainTeX

The advantage, if any, of the mp terminal over a postscript terminal is
 editable output.  Considerable effort went into making this output as clean as
 possible.  For those knowledgeable in the Metapost language, the default line
 types and colors can be changed by editing the arrays `lt[]` and `col[]`.
 The choice of solid vs dashed lines, and color vs black lines can be change by
 changing the values assigned to the booleans `dashedlines` and `colorlines`.
 If the default `tex` option was in effect, global changes to the text of
 labels can be achieved by editing the `vebatimtex...etex` block.  In
 particular, a LaTeX preamble can be added if desired, and then LaTeX's
 built-in size changing commands can be used for maximum flexibility. Be sure
 to set the appropriate MP configuration variable to force Metapost to run
 LaTeX instead of plainTeX.
?commands set terminal context
?set terminal context
?terminal context
?set term context
?term context
?context
 ConTeXt is a macro package for TeX, highly integrated with Metapost
 (for drawing figures) and intended for creation of high-quality PDF documents.
 The terminal outputs Metafun source, which can be edited manually,
 but you should be able to configure most things from outside.

For an average user of ConTeXt + gnuplot module it's recommended to refer to
 `Using ConTeXt` rather than reading this page
 or to read the manual of the gnuplot module for ConTeXt.

The `context` terminal supports the following options:

Syntax:
      set term context {default}
              {defaultsize | size <scale> | size <xsize>{in|cm}, <ysize>{in|cm}}
              {input | standalone}
              {timestamp | notimestamp}
              {noheader | header "<header>"}
              {color | colour | monochrome}
              {rounded | mitered | beveled} {round | butt | squared}
              {dashed | solid} {dashlength | dl <dl>}
              {linewidth | lw <lw>}
              {fontscale <fontscale>}
              {mppoints | texpoints}
              {inlineimages | externalimages}
              {defaultfont | font "{<fontname>}{,<fontsize>}"}

In non-standalone (`input`) graphic only parameters `size` to select graphic
 size, `fontscale` to scale all the labels for a factor <fontscale>
 and font size, make sense, the rest is silently
 ignored and should be configured in the .tex file which inputs the graphic.
 It's highly recommended to set the proper fontsize if document font differs from
 12pt, so that gnuplot will know how much space to reserve for labels.

`default` resets all the options to their default values.

`defaultsize` sets the plot size to 5in,3in.
 `size` <scale> sets the plot size to <scale> times <default value>.
 If two arguments are given (separated with ','), the first one sets
 the horizontal size and the second one the vertical size.
 Size may be given without units (in which case it means relative to the default
 value), with inches ('in') or centimeters ('cm').

`input` (default) creates a graphic that can be included into another ConTeXt
 document.
 `standalone` adds some lines, so that the document might be compiled as-is.
 You might also want to add `header` in that case.

Use `header` for any additional settings/definitions/macros
 that you might want to include in a standalone graphic. `noheader` is the default.

`notimestamp` prevents printing creation time in comments
 (if version control is used, one may prefer not to commit new version when only date changes).

`color` to make color plots is the default, but `monochrome` doesn't do anything special yet.
 If you have any good ideas how the behaviour should differ to suit the monochrome printers better,
 your suggestions are welcome.

`rounded` (default), `mitered` and `beveled` control the shape of line joins.
 `round` (default), `butt` and `squared` control the shape of line caps.
 See PostScript or PDF Reference Manual for explanation. For wild-behaving functions
 and thick lines
 it is better to use `rounded` and `round` to prevent sharp corners in line joins.
 (Some general support for this should be added to Gnuplot, so that the same options
 could be set for each line (style) separately).

`dashed` (default) uses different dash patterns for different line types,
 `solid` draws all plots with solid lines.

`dashlength` or `dl` scales the length of the dashed-line segments by <dl>.
 `linewidth` or `lw` scales all linewidths by <lw>.
 (lw 1 stands for 0.5bp, which is the default line width when drawing with Metapost.)
 `fontscale` scales text labels for factor <fontscale> relative to default document font.

`mppoints` uses predefined point shapes, drawn in Metapost.
 `texpoints` uses easily configurable set of symbols, defined with ConTeXt
 in the following way:
      \defineconversion[my own points][+,{\ss x},\mathematics{\circ}]
      \setupGNUPLOTterminal[context][points=tex,pointset=my own points]

`inlineimages` writes binary images to a string and only works in ConTeXt MKIV.
 `externalimages` writes PNG files to disk and also works with ConTeXt MKII.
 Gnuplot needs to have support for PNG images built in for this to work.

With `font` you can set font name and size in standalone graphics.
 In non-standalone (`input`) mode only the font size is important
 to reserve enough space for text labels.
 The command
      set term context font "myfont,ss,10"
 will result in
      \setupbodyfont[myfont,ss,10pt]
 If you additionally set `fontscale` to 0.8 for example,
 then the resulting font will be 8pt big and
      set label ... font "myfont,12"
 will come out as 9.6pt.

It is your own responsibility to provide proper typescripts (and header),
 otherwise switching the font will have no effect.
 For a standard font in ConTeXt MKII (pdfTeX) you could use:
      set terminal context standalone header '\usetypescript[iwona][ec]' \
          font "iwona,ss,11"
 Please take a look into ConTeXt documentation, wiki or mailing list (archives)
 for any up-to-date information about font usage.

Examples:
      set terminal context size 10cm, 5cm     # 10cm, 5cm
      set terminal context size 4in, 3in      # 4in, 3in
 For standalone (whole-page) plots with labels in UTF-8 encoding:
      set terminal context standalone header '\enableregime[utf-8]'

You need gnuplot module for ConTeXt
      http://ctan.org/pkg/context-gnuplot
 and a recent version of ConTeXt.
 If you want to call gnuplot on-the-fly, you also need write18 enabled.
 In most TeX distributions this can be set with shell_escape=t in texmf.cnf.

See
           http://wiki.contextgarden.net/Gnuplot
 for details about this terminal and for more exhaustive help & examples.

The easiest way to make plots in ConTeXt documents is
      \usemodule[gnuplot]
      \starttext
      \title{How to draw nice plots with {\sc gnuplot}?}
      \startGNUPLOTscript[sin]
      set format y "%.1f"
      plot sin(x) t '$\sin(x)$'
      \stopGNUPLOTscript
      \useGNUPLOTgraphic[sin]
      \stoptext
 This will run gnuplot automatically and include the resulting figure in the document.
?set terminal latex
?set term latex
?terminal latex
?term latex
?latex
 Gnuplot provides a variety of terminals for use with TeX/LaTeX.

(1) TeX/LaTeX compatible terminals based on use of PostScript
 See  `epslatex`, `pslatex`, `mp` (metapost),  and `pstricks`.

(2) TeX/LaTeX compatible terminals based on cairo graphics
 See `cairolatex`.

(3) The `tikz` terminal uses an external lua script (see `lua`)
 to produce files for the PGF and TikZ packages.
 Use the command `set term tikz help` to print terminal options.

(4) The `pict2e` terminal (new in version 5.4) replaces a set of legacy
 terminals `latex`, `emtex`, `eepic`, and `tpic` present in older versions
 of gnuplot. See `pict2e`.

(5) Others, see `context`, `mf` (metafont).

?set terminal wxt
?terminal wxt
?set term wxt
?term wxt
?wxt
 The `wxt` terminal device generates output in a separate window. The window
 is created by the wxWidgets library, where the 'wxt' comes from. The actual
 drawing is done via cairo, a 2D graphics library, and pango, a library for
 laying out and rendering text.

Syntax:
         set term wxt {<n>}
                      {size <width>,<height>} {position <x>,<y>}
                      {background <rgb_color> | nobackground}
                      {{no}enhanced}
                      {font <font>} {fontscale <scale>}
                      {title "title"}
                      {linewidth <lw>} {butt|rounded|square}
                      {dashlength <dl>}
                      {{no}persist}
                      {{no}raise}
                      {{no}ctrl}
                      {close}

Multiple plot windows are supported: `set terminal wxt <n>` directs the
 output to plot window number n.

The default window title is based on the window number. This title can also
 be specified with the keyword "title".

Plot windows remain open even when the `gnuplot` driver is changed to a
 different device.  A plot window can be closed by pressing the letter 'q'
 while that window has input focus, by choosing `close` from a window
 manager menu, or with `set term wxt <n> close`.

The size of the plot area is given in pixels, it defaults to 640x384.
 In addition to that, the actual size of the window also includes the space
 reserved for the toolbar and the status bar.
 When you resize a window, the plot is immediately scaled to fit in the
 new size of the window. Unlike other interactive terminals, the `wxt`
 terminal scales the whole plot, including fonts and linewidths, and keeps
 its global aspect ratio constant, leaving an empty space painted in gray.
 If you type `replot`, click the `replot` icon in the terminal toolbar or
 type a new `plot` command, the new plot will completely fit in the window
 and the font size and the linewidths will be reset to their defaults.

The position option can be used to set the position of the plot window.
 The position option only applies to the first plot after the `set term`
 command.

The active plot window (the one selected by `set term wxt <n>`) is
 interactive. Its behaviour is shared with other terminal types. See `mouse`
 for details. It also has some extra icons, which are supposed to be
 self-explanatory.

This terminal supports an enhanced text mode, which allows font and other
 formatting commands (subscripts, superscripts, etc.) to be embedded in labels
 and other text strings. The enhanced text mode syntax is shared with other
 gnuplot terminal types. See `enhanced` for more details.

<font> is in the format "FontFace,FontSize", i.e. the face and the size
 comma-separated in a single string. FontFace is a usual font face name, such
 as 'Arial'. If you do not provide FontFace, the wxt terminal will use
 'Sans'. FontSize is the font size, in points. If you do not provide it,
 the wxt terminal will use a size of 10 points.
    For example :
       set term wxt font "Arial,12"
       set term wxt font "Arial" # to change the font face only
       set term wxt font ",12" # to change the font size only
       set term wxt font "" # to reset the font name and size

The fonts are retrieved from the usual fonts subsystems. Under Windows,
 those fonts are to be found and configured in the entry "Fonts" of the
 control panel. Under UNIX, they are handled by "fontconfig".

Pango, the library used to layout the text, is based on utf-8. Thus, the wxt
 terminal has to convert from your encoding to utf-8. The default input
 encoding is based on your 'locale'. If you want to use another encoding,
 make sure gnuplot knows which one you are using. See `encoding` for more
 details.

Pango may give unexpected results with fonts that do not respect the unicode
 mapping. With the Symbol font, for example, the wxt terminal will use the map
 provided by http://www.unicode.org/ to translate character codes to unicode.
 Pango will do its best to find a font containing this character, looking for
 your Symbol font, or other fonts with a broad unicode coverage, like the
 DejaVu fonts. Note that "the Symbol font" is to be understood as the Adobe
 Symbol font, distributed with Acrobat Reader as "SY______.PFB".
 Alternatively, the OpenSymbol font, distributed with OpenOffice.org as
 "opens___.ttf", offers the same characters. Microsoft has distributed a
 Symbol font ("symbol.ttf"), but it has a different character set with
 several missing or moved mathematic characters. If you experience problems
 with your default setup (if the demo enhancedtext.dem is not displayed
 properly for example), you probably have to install one of the Adobe or
 OpenOffice Symbol fonts, and remove the Microsoft one.
 Other non-conform fonts, such as "wingdings" have been observed working.

The rendering of the plot can be altered with a dialog available from the
 toolbar. To obtain the best output possible, the rendering involves three
 mechanisms : antialiasing, oversampling and hinting.
 Antialiasing allows to display non-horizontal and non-vertical lines
 smoother.
 Oversampling combined with antialiasing provides subpixel accuracy,
 so that gnuplot can draw a line from non-integer coordinates. This avoids
 wobbling effects on diagonal lines ('plot x' for example).
 Hinting avoids the blur on horizontal and vertical lines caused by
 oversampling. The terminal will snap these lines to integer coordinates so
 that a one-pixel-wide line will actually be drawn on one and only one pixel.

By default, the window is raised to the top of your desktop when a plot is
 drawn. This can be controlled with the keyword "raise".
 The keyword "persist" will prevent gnuplot from exiting before you
 explicitly close all the plot windows.
 Finally, by default the key <space> raises the gnuplot console window, and
 'q' closes the plot window. The keyword "ctrl" allows you to replace those
 bindings by <ctrl>+<space> and <ctrl>+'q', respectively.
 These three keywords (raise, persist and ctrl) can also be set and remembered
 between sessions through the configuration dialog.
?set terminal epscairo
?terminal epscairo
?set term epscairo
?term epscairo
?epscairo
 The `epscairo` terminal device generates encapsulated PostScript (*.eps) using
 the cairo and pango support libraries.  cairo version >= 1.6 is required.

Please read the help for the `pdfcairo` terminal.
?set terminal cairolatex
?terminal cairolatex
?set term cairolatex
?term cairolatex
?cairolatex
 The `cairolatex` terminal device generates encapsulated PostScript (*.eps),
 PDF, or PNG output using the cairo and pango support libraries and uses LaTeX
 for text output using the same routines as the `epslatex` terminal.

Syntax:
       set terminal cairolatex
                      {eps | pdf | png}
                      {standalone | input}
                      {blacktext | colortext | colourtext}
                      {header <header> | noheader}
                      {mono|color}
                      {{no}transparent} {{no}crop} {background <rgbcolor>}
                      {font <font>} {fontscale <scale>}
                      {linewidth <lw>} {rounded|butt|square} {dashlength <dl>}
                      {size <XX>{unit},<YY>{unit}}
                      {resolution <dpi>}

The cairolatex terminal prints a plot like `terminal epscairo` or
 `terminal pdfcairo` but transfers the texts to LaTeX instead of including
 them in the graph. For reference of options not explained here see `pdfcairo`.

`eps`, `pdf`, or `png` select the type of graphics output. Use `eps` with
 latex/dvips and `pdf` for pdflatex.  If your plot has a huge number
 of points use `png` to keep the filesize down.  When using the `png` option,
 the terminal accepts an extra option `resolution` to control the pixel
 density of the resulting PNG.  The argument of `resolution` is an integer
 with the implied unit of DPI.

`blacktext` forces all text to be written in black even in color mode;

The `cairolatex` driver offers a special way of controlling text positioning:
 (a) If any text string begins with '{', you also need to include a '}' at the
 end of the text, and the whole text will be centered both horizontally
 and vertically by LaTeX.  (b) If the text string begins with '[', you need
 to continue it with: a position specification (up to two out of t,b,l,r,c),
 ']{', the text itself, and finally, '}'. The text itself may be anything
 LaTeX can typeset as an LR-box. \rule{}{}'s may help for best positioning.
 See also the documentation for the `pslatex` terminal driver.
 To create multiline labels, use \shortstack, for example
    set ylabel '[r]{\shortstack{first line \\ second line}}'

The driver produces two different files, one for the eps, pdf, or png part of
 the figure and one for the LaTeX part. The name of the LaTeX file is taken
 from the `set output` command. The name of the eps/pdf/png file is derived by
 replacing the file extension (normally '.tex') with '.eps'/'.pdf'/'.png'
 instead. There is no LaTeX output if no output file is given!  Remember to
 close the `output file` before next plot unless in `multiplot` mode.

In your LaTeX documents use '\input{filename}' to include the figure.
 The '.eps'/'.pdf'/'.png' file is included by the command
 \includegraphics{...}, so you must also include \usepackage{graphicx} in
 the LaTeX preamble.  If you want to use coloured text (option `colourtext`)
 you also have to include \usepackage{color} in the LaTeX preamble.

The behaviour concerning font selection depends on the header mode.
 In all cases, the given font size is used for the calculation of proper
 spacing. When not using the `standalone` mode the actual LaTeX font and
 font size at the point of inclusion is taken, so use LaTeX commands for
 changing fonts. If you use e.g. 12pt as font size for your LaTeX
 document, use '", 12"' as options. The font name is ignored. If using
 `standalone` the given font and font size are used, see below for a
 detailed description.

When using the cairolatex terminal give the name of the TeX file in the
 `set output` command including the file extension (normally ".tex").
 The graph filename is generated by replacing the extension.

If using the `standalone` mode a complete LaTeX header is added to the
 LaTeX file; and "-inc" is added to the filename of the gaph file.
 The `standalone` mode generates a TeX file that produces
 output with the correct size when using dvips, pdfTeX, or VTeX.
 The default, `input`, generates a file that has to be included into a
 LaTeX document using the \input command.

If a font other than "" or "default" is given it is interpreted as
 LaTeX font name.  It contains up to three parts, separated by a comma:
 'fontname,fontseries,fontshape'.  If the default fontshape or fontseries
 are requested, they can be omitted.  Thus, the real syntax for the fontname
 is '{fontname}{,fontseries}{,fontshape}'.  The naming convention for all
 parts is given by the LaTeX font scheme.  The fontname is 3 to 4 characters
 long and is built as follows: One character for the font vendor, two
 characters for the name of the font, and optionally one additional
 character for special fonts, e.g., 'j' for fonts with old-style numerals
 or 'x' for expert fonts. The names of many fonts is described in
           http://www.tug.org/fontname/fontname.pdf
 For example, 'cmr' stands for Computer Modern Roman, 'ptm' for Times-Roman,
 and 'phv' for Helvetica.  The font series denotes the thickness of the
 glyphs, in most cases 'm' for normal ("medium") and 'bx' or 'b' for bold
 fonts.  The font shape is 'n' for upright, 'it' for italics, 'sl' for
 slanted, or 'sc' for small caps, in general.  Some fonts may provide
 different font series or shapes.

Examples:

Use Times-Roman boldface (with the same shape as in the surrounding text):
       set terminal cairolatex font 'ptm,bx'
 Use Helvetica, boldface, italics:
       set terminal cairolatex font 'phv,bx,it'
 Continue to use the surrounding font in slanted shape:
       set terminal cairolatex font ',,sl'
 Use small capitals:
       set terminal cairolatex font ',,sc'

By this method, only text fonts are changed. If you also want to change
 the math fonts you have to use the "gnuplot.cfg" file or the `header`
 option, described below.

In `standalone` mode, the font size is taken from the given font size in the
 `set terminal` command. To be able to use a specified font size, a file
 "size<size>.clo" has to reside in the LaTeX search path.  By default,
 10pt, 11pt, and 12pt are supported.  If the package "extsizes" is
 installed, 8pt, 9pt, 14pt, 17pt, and 20pt are added.

The `header` option takes a string as argument.  This string is written
 into the generated LaTeX file.  If using the `standalone` mode, it is
 written into the preamble, directly before the \begin{document} command.
 In the `input` mode, it is placed directly after the \begingroup command
 to ensure that all settings are local to the plot.

Examples:

Use T1 fontencoding, change the text and math font to Times-Roman as well
 as the sans-serif font to Helvetica:
     set terminal cairolatex standalone header \
     "\\usepackage[T1]{fontenc}\n\\usepackage{mathptmx}\n\\usepackage{helvet}"
 Use a boldface font in the plot, not influencing the text outside the plot:
     set terminal cairolatex input header "\\bfseries"

?set terminal pdfcairo
?terminal pdfcairo
?set term pdfcairo
?term pdfcairo
?pdfcairo
 The `pdfcairo` terminal device generates output in pdf. The actual
 drawing is done via cairo, a 2D graphics library, and pango, a library for
 laying out and rendering text.

Syntax:
         set term pdfcairo
                      {{no}enhanced} {mono|color}
                      {font <font>} {fontscale <scale>}
                      {linewidth <lw>} {rounded|butt|square} {dashlength <dl>}
                      {background <rgbcolor>}
                      {size <XX>{unit},<YY>{unit}}

The width of all lines in the plot can be modified by the factor <lw>
 specified in `linewidth`. The default linewidth is 0.5 points.
 (1 "PostScript" point = 1/72 inch = 0.353 mm)

`rounded` sets line caps and line joins to be rounded;
 `butt` is the default, butt caps and mitered joins.

The default size for the output is 5 inches x 3 inches. The `size` option
 changes this to whatever the user requests. By default the X and Y sizes are
 taken to be in inches, but other units are possible (currently only cm).
 Screen coordinates always run from 0.0 to 1.0 along the full length of the
 plot edges as specified by the `size` option.

<font> is in the format "FontFace,FontSize", i.e. the face and the size
 comma-separated in a single string. FontFace is a usual font face name, such
 as 'Arial'. If you do not provide FontFace, the pdfcairo terminal will use
 'Sans'. FontSize is the font size, in points. If you do not provide it,
 the pdfcairo terminal will use a nominal font size of 12 points.
 However, the default fontscale parameter for this terminal is 0.5,
 so the apparent font size is smaller than this if the pdf output is
 viewed at full size.
    For example :
       set term pdfcairo font "Arial,12"
       set term pdfcairo font "Arial" # to change the font face only
       set term pdfcairo font ",12" # to change the font size only
       set term pdfcairo font "" # to reset the font name and size

Pango, the library used to layout the text, is based on utf-8. Thus, the pdfcairo
 terminal has to convert from your encoding to utf-8. The default input
 encoding is based on your 'locale'. If you want to use another encoding,
 make sure gnuplot knows which one you are using. See `encoding` for more
 details.

Pango may give unexpected results with fonts that do not respect the unicode
 mapping. With the Symbol font, for example, the pdfcairo terminal will use the map
 provided by http://www.unicode.org/ to translate character codes to unicode.
 Note that "the Symbol font" is to be understood as the Adobe
 Symbol font, distributed with Acrobat Reader as "SY______.PFB".
 Alternatively, the OpenSymbol font, distributed with OpenOffice.org as
 "opens___.ttf", offers the same characters. Microsoft has distributed a
 Symbol font ("symbol.ttf"), but it has a different character set with
 several missing or moved mathematic characters. If you experience problems
 with your default setup (if the demo enhancedtext.dem is not displayed
 properly for example), you probably have to install one of the Adobe or
 OpenOffice Symbol fonts, and remove the Microsoft one.
 Other non-conform fonts, such as "wingdings" have been observed working.

The rendering of the plot cannot be altered yet. To obtain the best output
 possible, the rendering involves two mechanisms : antialiasing and
 oversampling.
 Antialiasing allows to display non-horizontal and non-vertical lines
 smoother.
 Oversampling combined with antialiasing provides subpixel accuracy,
 so that gnuplot can draw a line from non-integer coordinates. This avoids
 wobbling effects on diagonal lines ('plot x' for example).

?set terminal pngcairo
?terminal pngcairo
?set term pngcairo
?term pngcairo
?pngcairo
 The `pngcairo` terminal device generates output in png. The actual
 drawing is done via cairo, a 2D graphics library, and pango, a library for
 laying out and rendering text.

Syntax:
         set term pngcairo
                      {{no}enhanced} {mono|color}
                      {{no}transparent} {{no}crop} {background <rgbcolor>
                      {font <font>} {fontscale <scale>}
                      {linewidth <lw>} {rounded|butt|square} {dashlength <dl>}
                      {pointscale <ps>}
                      {size <XX>{unit},<YY>{unit}}

The width of all lines in the plot can be modified by the factor <lw>.

`rounded` sets line caps and line joins to be rounded;
 `butt` is the default, butt caps and mitered joins.

The default size for the output is 640 x 480 pixels. The `size` option
 changes this to whatever the user requests. By default the X and Y sizes are
 taken to be in pixels, but other units are possible (currently cm and inch).
 A size given in centimeters or inches will be converted into pixels assuming
 a resolution of 72 dpi. Screen coordinates always run from 0.0 to 1.0 along
 the full length of the plot edges as specified by the `size` option.

<font> is in the format "FontFace,FontSize", i.e. the face and the size
 comma-separated in a single string. FontFace is a usual font face name, such
 as 'Arial'. If you do not provide FontFace, the pngcairo terminal will use
 'Sans'. FontSize is the font size, in points. If you do not provide it,
 the pngcairo terminal will use a size of 12 points.
    For example :
       set term pngcairo font "Arial,12"
       set term pngcairo font "Arial" # to change the font face only
       set term pngcairo font ",12" # to change the font size only
       set term pngcairo font "" # to reset the font name and size

Pango, the library used to layout the text, is based on utf-8. Thus, the pngcairo
 terminal has to convert from your encoding to utf-8. The default input
 encoding is based on your 'locale'. If you want to use another encoding,
 make sure gnuplot knows which one you are using. See `encoding` for more detail.

Pango may give unexpected results with fonts that do not respect the unicode
 mapping. With the Symbol font, for example, the pngcairo terminal will use the map
 provided by http://www.unicode.org/ to translate character codes to unicode.
 Note that "the Symbol font" is to be understood as the Adobe
 Symbol font, distributed with Acrobat Reader as "SY______.PFB".
 Alternatively, the OpenSymbol font, distributed with OpenOffice.org as
 "opens___.ttf", offers the same characters. Microsoft has distributed a
 Symbol font ("symbol.ttf"), but it has a different character set with
 several missing or moved mathematic characters. If you experience problems
 with your default setup (if the demo enhancedtext.dem is not displayed
 properly for example), you probably have to install one of the Adobe or
 OpenOffice Symbol fonts, and remove the Microsoft one.

Rendering uses oversampling, antialiasing, and font hinting to the extent
 supported by the cairo and pango libraries.

?commands set terminal lua
?set terminal lua
?set term lua
?terminal lua
?term lua
?lua
 The `lua` generic terminal driver works in conjunction with an
 external Lua script to create a target-specific plot file.
 Currently the only supported target is TikZ -> pdflatex.

Information about Lua is available at http://www.lua.org .

Syntax:
    set terminal lua <target name> | "<file name>"
                        {<script_args> ...}
                        {help}

A 'target name' or 'file name' (in quotes) for a script is mandatory.
 If a 'target name' for the script is given, the terminal will look for
 "gnuplot-<target name>.lua" in the local directory and on failure in
 the environmental variable GNUPLOT_LUA_DIR.

All arguments will be provided to the selected script for further
 evaluation. E.g. 'set term lua tikz help' will cause the script itself
 to print additional help on options and choices for the script.
?set terminal lua tikz
?set term lua tikz
?term lua tikz
 The TikZ driver is one output mode of the generic Lua terminal.

Syntax:
     set terminal lua tikz

{latex | tex | context}
      {color | monochrome}
      {nooriginreset | originreset}
      {nogparrows | gparrows}
      {nogppoints | gppoints}
      {picenvironment | nopicenvironment}
      {noclip | clip}
      {butt}
      {notightboundingbox | tightboundingbox}
      {background "<colorpec>"}
      {size <x>{unit},<y>{unit}}
      {scale <x>,<y>}
      {plotsize <x>{unit},<y>{unit}}
      {charsize <x>{unit},<y>{unit}}
      {font "<fontdesc>"}
      {{fontscale | textscale} <scale>}
      {dashlength | dl <DL>}
      {linewidth | lw <LW>}
      {nofulldoc | nostandalone | fulldoc | standalone}
      {{preamble | header} "<preamble_string>"}
      {tikzplot <ltn>,...}
      {notikzarrows | tikzarrows}
      {rgbimages | cmykimages}
      {noexternalimages|externalimages}
      {bitmap | nobitmap}
      {providevars <var name>,...}
      {createstyle}
      {help}

For all options that expect lengths as their arguments they
 will default to 'cm' if no unit is specified. For all lengths
 the following units may be used: 'cm', 'mm', 'in' or 'inch',
 'pt', 'pc', 'bp', 'dd', 'cc'. Blanks between numbers and units
 are not allowed.

'monochrome' disables line coloring and switches to grayscaled
 fills.

'originreset' moves the origin of the TikZ picture to the lower
 left corner of the plot. It may be used to align several plots
 within one tikzpicture environment. This is not tested with
 multiplots and pm3d plots!

'gparrows' use gnuplot's internal arrow drawing function
 instead of the ones provided by TikZ.

'gppoints' use gnuplot's internal plotmark drawing function
 instead of the ones provided by TikZ.

'nopicenvironment' omits the declaration of the 'tikzpicture'
 environment in order to set it manually. This permits putting
 some PGF/TikZ code directly before or after the plot.

'clip' crops the plot at the defined canvas size. Default is
 'noclip' by which only a minimum bounding box of the canvas size
 is set. Neither a fixed bounding box nor a crop box is set if the
 'plotsize' or 'tightboundingbox' option is used.

'butt' changes the linecap property to "butt" and the linejoin
 property to "miter".  The defaults are "round" and "round".

If 'tightboundingbox' is set the 'clip' option is ignored and the
 final bounding box is the natural bounding box calculated by tikz.

'background' sets the background color to the value specified in
 the <colorpec> argument. <colorspec> must be a valid color name or
 a 3 byte RGB code as a hexadecimal number with a preceding number
 sign ('#'). E.g. '#ff0000' specifies pure red. If omitted the
 background is transparent.

The 'size' option expects two lengths <x> and <y> as the canvas
 size. The default size of the canvas is 12.5cm x 8.75cm.

The 'scale' option works similar to the 'size' option but expects
 scaling factors <x> and <y> instead of lengths.

The 'plotsize' option permits setting the size of the plot area
 instead of the canvas size, which is the usual gnuplot behaviour.
 Using this option may lead to slightly asymmetric tic lengths.
 Like 'originreset' this option may not lead to convenient results
 if used with multiplots or pm3d plots. An alternative approach
 is to set all margins to zero and to use the 'noclip' option.
 The plot area has then the dimensions of the given canvas sizes.

The 'charsize' option expects the average horizontal and vertical
 size of the used font. Look at the generated style file for an
 example of how to use it from within your TeX document.

'fontscale' or 'textscale' expects a scaling factor as a parameter.
 All texts in the plot are scaled by this factor then.

'dashlength' or 'dl' scales the length of dashed-line segments by <DL>,
 which is a floating-point number greater than zero. 'linewidth' or 
 'lw' scales all linewidths by <LW>.

The options 'tex', 'latex' and 'context' choose the TeX output
 format. LaTeX is the default. To load the style file put the
 according line at the beginning of your document:
   \input gnuplot-lua-tikz.tex    % (for plain TeX)
   \usepackage{gnuplot-lua-tikz}  % (for LaTeX)
   \usemodule[gnuplot-lua-tikz]   % (for ConTeXt)

'createstyle' derives the TeX/LaTeX/ConTeXt styles from the script
 and writes them to the appropriate files.

'fulldoc' or 'standalone' produces a full LaTeX document for direct
 compilation.

'preamble' or 'header' may be used to put any additional LaTeX code
 into the document preamble in standalone mode.

With the 'tikzplot' option the '\path plot' command will be used
 instead of only '\path'. The following list of numbers of linetypes
 (<ltn>,...) defines the affected plotlines. There exists a plotstyle
 for every linetype. The default plotstyle is 'smooth' for every
 linetype >= 1.

By default the tikz terminal produces simple LaTeX arrows.
 To produce arrows in accord with gnuplot's 'arrowstyle' settings,
 use the 'gparrows' option.  The 'tikzarrows' option is a third alternative
 that bypasses both of these. Instead the arrowstyle 'angle' parameter is
 used to index a set of 12 pre-defined TikZ arrow styles.
 E.g. an arrow style with the angle '7' will be mapped to the TikZ style
 'gp arrow 7' ignoring all other arrowstyle settings.

With 'cmykimages' the CMYK color model will be used for inline image data
 instead of the RGB model. All other colors (like line colors etc.) are
 not affected by this option, since they are handled e.g. by LaTeX's
 xcolor package. This option is ignored if images are externalized.

By using the 'externalimages' option all bitmap images will be written
 as external PNG images and included at compile time of the document.
 Generating DVI and later postscript files requires to convert the PNGs
 into EPS files in a separate step e.g. by using ImageMagick's `convert`.
 Transparent bitmap images are always generated as an external PNGs.

The 'nobitmap' option let images be rendered as filled rectangles instead
 of the nativ PS or PDF inline image format. This option is ignored if
 images are externalized.

The 'providevars' options makes gnuplot's internal and user variables
 available by using the '\gpgetvar{<var name>}' command within the TeX
 script. Use gnuplot's 'show variables all' command to see the list
 of valid variables.

The <fontdesc> string may contain any valid TeX/LaTeX/ConTeXt font commands
 like e.g. '\small'. It is passed directly as a node parameter in form of
 "font={<fontdesc>}". This can be 'misused' to add further code to a node,
 e.g. '\small,yshift=1ex' or ',yshift=1ex' are also valid while the
 latter does not change the current font settings. One exception is
 the second argument of the list. If it is a number of the form
 <number>{unit} it will be interpreted as a fontsize like in other
 terminals and will be appended to the first argument. If the unit is
 omitted the value is interpreted as 'pt'. As an example the string
 '\sffamily,12,fill=red' sets the font to LaTeX's sans serif font at
 a size of 12pt and red background color.
 The same applies to ConTeXt, e.g. '\switchtobodyfont[iwona],10' changes the
 font to Iwona at a size of 10pt.
 Plain TeX users have to change the font size explicitly within the first
 argument. The second should be set to the same value to get proper scaling
 of text boxes.

Strings have to be put in single or double quotes. Double quoted
 strings may contain special characters like newlines '\n' etc.

?commands set terminal tikz
?set terminal tikz
?set term tikz
?terminal tikz
?term tikz
?tikz
 This driver creates output for use with the TikZ package of graphics macros
 in TeX.  It is currently implemented via an external lua script, and 
 `set term tikz` is a short form of the command `set term lua tikz`.
 See `term lua` for more information.  Use the command `set term tikz help`
 to print terminal options.
?set terminal qt
?terminal qt
?set term qt
?term qt
?qt
 The `qt` terminal device generates output in a separate window with the Qt library.
 Syntax:
         set term qt {<n>}
                     {size <width>,<height>}
                     {position <x>,<y>}
                     {title "title"}
                     {font <font>} {{no}enhanced}
                     {linewidth <lw>} {dashlength <dl>}
                     {{no}persist} {{no}raise} {{no}ctrl}
                     {close}
                     {widget <id>}

Multiple plot windows are supported: `set terminal qt <n>` directs the
 output to plot window number n.

The default window title is based on the window number. This title can also
 be specified with the keyword "title".

Plot windows remain open even when the `gnuplot` driver is changed to a
 different device. A plot window can be closed by pressing the letter 'q'
 while that window has input focus, by choosing `close` from a window
 manager menu, or with `set term qt <n> close`.

The size of the plot area is given in pixels, it defaults to 640x480.
 In addition to that, the actual size of the window also includes the space
 reserved for the toolbar and the status bar.
 When you resize a window, the plot is immediately scaled to fit in the
 new size of the window. The `qt` terminal scales the whole plot, including
 fonts and linewidths, and keeps its global aspect ratio constant.
 If you type `replot`, click the `replot` icon in the terminal toolbar or
 type a new `plot` command, the new plot will completely fit in the window
 and the font size and the linewidths will be reset to their defaults.

The position option can be used to set the position of the plot window.
 The position option only applies to the first plot after the `set term`
 command.

The active plot window (the one selected by `set term qt <n>`) is
 interactive. Its behaviour is shared with other terminal types. See `mouse`
 for details. It also has some extra icons, which are supposed to be
 self-explanatory.

<font> is in the format "FontFace,FontSize", i.e. the face and the size
 comma-separated in a single string. FontFace is a usual font face name, such
 as 'Arial'. If you do not provide FontFace, the qt terminal will use
 'Sans'. FontSize is the font size, in points. If you do not provide it,
 the qt terminal will use a size of 9 points.
    For example :
       set term qt font "Arial,12"
       set term qt font "Arial" # to change the font face only
       set term qt font ",12" # to change the font size only
       set term qt font "" # to reset the font name and size

The dashlength affects only custom dash patterns, not Qt's built-in set.

To obtain the best output possible, the rendering involves three
 mechanisms : antialiasing, oversampling and hinting.
 Oversampling combined with antialiasing provides subpixel accuracy,
 so that gnuplot can draw a line from non-integer coordinates. This avoids
 wobbling effects on diagonal lines ('plot x' for example).
 Hinting avoids the blur on horizontal and vertical lines caused by
 oversampling. The terminal will snap these lines to integer coordinates so
 that a one-pixel-wide line will actually be drawn on one and only one pixel.

The <space> key raises the gnuplot console window [MS Windows only].
 The 'q' key closes the plot window. These hot keys can be changed to
 ctrl-space and ctrl-q using the terminal option keyword "{no}ctrl".
 However the preferred way to select ctrl-q rather than 'q' is to use
 the toggle in the tools widget of the plot window.

The gnuplot outboard driver, gnuplot_qt, is searched in a default place
 chosen when the program is compiled.  You can override that by defining
 the environment variable GNUPLOT_DRIVER_DIR.
?bugs
 Please e-mail bug reports to the gnuplot-bugs mailing list or
 upload the report to the gnuplot web site on SourceForge.
 Please give complete information on the version of gnuplot you are using
 and, if possible, a test script that demonstrates the bug.
 See `seeking-assistance`.

It is not possible to use inline data (e.g. plot '-' ...) inside the curly
 brackets of a `do` or `while` loop.

X11 terminal: It is difficult to select UTF-8 fonts.
 Only one color palette at a time is active for any given x11 plot window.
 This means that multiplots whose constituent plots use different
 palettes will not display correctly in x11.

Qt terminal: 3D rotation of polygons and surfaces can be slow;
 this is strongly affected by the Qt rendering mode (see Qt documentation).

The `raise` and `lower` commands are unreliable.

?bugs external_libraries
 External library GD (used by PNG/JPEG/GIF/sixelgd terminals, pixmap):
 Versions of libgd through 2.0.33 had various bugs in mapping the characters
 of Adobe's Symbol font.
 Dot-dash patterns are not supported for these terminals.

External library PDFlib (used by PDF terminal, but not by pdfcairo):
 Gnuplot can be linked against libpdf versions 4, 5, or 6. However, these
 versions differ in their handling of piped I/O.  Therefore gnuplot scripts
 using piped output to PDF may work only for some versions of PDFlib.

Internationalization (locale settings):
 Gnuplot uses the C runtime library routine setlocale() to control
 locale-specific formatting of input and output number, times, and date strings.
 The locales available, and the level of support for locale features such as
 "thousands' grouping separator", depend on the internationalization support
 provided by your individual machine.

External library libcerf versions 1.8 1.9 1.10 return incorrect results for
 the voigt function. Do not use.

${this.title}

Code Editor : gnuplot.gih