plot - translate GNU metafiles to other graphics formats
plot [ options ] [ files ]
plot translates files in GNU metafile format to other graphics formats,
or displays them on an X Window System display. GNU metafile format is
a device-independent format for the storage of graphic data. It is the
default output format of the programs graph(1), pic2plot(1),
tek2plot(1), and plotfont(1), and is further documented in plot(5),
since it is an enhanced version of the traditional plot(5) format found
on non-GNU systems. It can also be produced by the GNU libplot 2-D
graphics export library (see plot(3)).
The output format is specified with the -T option. The possible output
formats and display types are the same as those supported by graph(1),
plotfont(1), pic2plot(1), and tek2plot(1). If an output file is
produced, it is written to standard output.
Options and file names may be interspersed on the command line, but the
options are processed before the file names are read. If -- is seen,
it is interpreted as the end of the options. If no file names are
specified, or the file name - is encountered, the standard input is
Select type as the output format. It may be "X", "png", "pnm",
"gif", "svg", "ai", "ps", "cgm", "fig", "pcl", "hpgl", "regis",
"tek", or "meta" (the default). These refer respectively to the
X Window System, PNG (Portable Network Graphics) format,
portable anymap format (PBM/PGM/PPM), a pseudo-GIF format that
does not use LZW encoding, the new XML-based Scalable Vector
Graphics format, the format used by Adobe Illustrator,
Postscript or Encapsulated Postscript (EPS) that can be edited
with idraw(1), CGM format (by default, confirming to the WebCGM
profile), the format used by the xfig(1) drawing editor, the
Hewlett-Packard PCL 5 printer language, the Hewlett-Packard
Graphics Language, ReGIS graphics format (which can be displayed
by the dxterm(1) terminal emulator or by a VT330 or VT340
terminal), Tektronix format (which can be displayed by the
xterm(1) terminal emulator), and device-independent GNU metafile
format itself. Unless type is "X", an output file is produced
and written to standard output.
Omitting the -T option is equivalent to specifying -T meta.
Translating from metafile format to itself is occasionally
useful, since there are two versions of metafile format (see the
-O option below).
A listing of the fonts available in any specified output format
may be obtained with the --help-fonts option (see below). If a
requested font is unavailable, a default font will be
substituted. The default font is "Helvetica" for "X", "svg",
"ai", "ps", "cgm", and "fig", "Univers" for "pcl", and
"HersheySerif" for "png", "pnm", "gif", "hpgl", "regis", "tek",
Output only page number n, within the metafile or sequence of
metafiles that is being translated.
Metafiles may consist of one or more pages, numbered beginning
with 1. Also, each page may contain multiple `frames'. plot -T
X, plot -T regis, and plot -T tek, which plot in real time, will
separate successive frames by screen erasures. plot -T png,
plot -T pnm, plot -T gif, plot -T svg, plot -T ai, plot -T ps,
plot -T cgm, plot -T fig, plot -T pcl, and plot -T hpgl, which
do not plot in real time, will output only the last frame of any
The default behavior, if -p is not used, is to output all pages.
For example, plot -T X displays each page in its own X window.
If the -T png, -T pnm, -T gif, -T ai, or -T fig option is used,
the default behavior is to output only the first nonempty page,
since files in those output formats contain only a single page
Metafiles produced by graph(1) and plotfont(1) contain only a
single page (page #1), which consists of two frames: an empty
frame to clear the display, and a second frame that contains the
Merge all displayed pages into a single page, and also merge all
This option is useful when merging together single-page plots
from different sources. For example, it can be used to merge
together plots obtained from separate invocations of graph(1).
Set the size of the graphics display in which the plot will be
drawn, in terms of pixels, to be bitmap_size. The default is
"570x570". This is relevant only to plot -T X, plot -T png,
plot -T pnm, and plot -T gif, all of which produce bitmaps. If
you choose a rectangular (non-square) window size, the fonts in
the plot will be scaled anisotropically, i.e., by different
factors in the horizontal and vertical directions. For plot -T
X, this requires an X11R6 display. Any font that cannot be
scaled in this way will be replaced by a default scalable font,
such as the vector font "HersheySerif".
The environment variable BITMAPSIZE can equally well be used to
specify the window size. For backward compatibility, the X
resource Xplot.geometry may be used instead.
If option is yes, replace each color in the output by an
appropriate shade of gray. This is seldom useful, except when
using plot -T pcl to prepare output for a PCL 5 device. (Many
monochrome PCL 5 devices, such as monochrome LaserJets, do a
poor job of emulating color on their own.) You may equally well
request color emulation by setting the environment variable
EMULATE_COLOR to "yes".
Set the maximum number of points that a polygonal line may
contain, before it is flushed out, to be max_line_length. If
this flushing occurs, the polygonal line will be split into two
or more sub-lines, though the splitting should not be
noticeable. The default value of max_line_length is 500.
The reason for splitting long polygonal lines is that some
display devices (e.g., old Postscript printers and pen HP-GL
plotters) have limited buffer sizes. The environment variable
MAX_LINE_LENGTH can also be used to specify the maximum line
Set the size of the page on which the plot will be positioned.
This is relevant only to plot -T svg, plot -T ai, plot -T ps,
plot -T cgm, plot -T fig, plot -T pcl, and plot -T hpgl. The
default is "letter", which means an 8.5 inch by 11 inch page.
Any ISO page size in the range "a0"..."a4" or ANSI page size in
the range "a"..."e" may be specified ("letter" is an alias for
"a" and "tabloid" is an alias for "b"). "legal" and "ledger"
are recognized page sizes also. The environment variable
PAGESIZE can equally well be used to specify the page size.
The graphics display in which the plot is drawn will, by
default, be a square region that occupies nearly the full width
of the specified page. An alternative size for the graphics
display can be specified. For example, the page size could be
specified as "letter,xsize=4in,ysize=6in", or
"a4,xsize=5.0cm,ysize=100mm". For all of the above except plot
-T hpgl, the graphics display will, by default, be centered on
the page. For all of the above except plot -T svg and plot -T
cgm, the graphics display may be repositioned manually, by
specifying the location of its lower left corner, relative to
the lower left corner of the page. For example, the page size
could be specified as "letter,xorigin=2in,yorigin=3in", or
"a4,xorigin=0.5cm,yorigin=0.5cm". It is also possible to
specify an offset vector. For example, the page size could be
specified as "letter,xoffset=1in", or
"letter,xoffset=1in,yoffset=1.2in", or "a4,yoffset=-1cm". In
SVG format and WebCGM format it is possible to specify the size
of the graphics display, but not its position.
Rotate the graphics display by angle degrees. Recognized values
are "0", "90", "180", and "270". "no" and "yes" are equivalent
to "0" and "90", respectively. The environment variable
ROTATION can also be used to specify a rotation angle.
Parameter Initialization Options
The following options set the initial values of drawing parameters.
However, all of these may be overridden by directives in a metafile.
In fact, these options are useful primarily when plotting old metafiles
in the traditional (pre-GNU) plot(5) format, which did not support such
Set the color initially used for the background to be name.
This is relevant only to plot -T X, plot -T png, plot -T pnm,
plot -T gif, plot -T svg, plot -T cgm, and plot -T regis. An
unrecognized name sets the color to the default, which is
"white". The environment variable BG_COLOR can equally well be
used to specify the background color.
If the -T png or -T gif option is used, a transparent PNG file
or a transparent pseudo-GIF, respectively, may be produced by
setting the TRANSPARENT_COLOR environment variable to the name
of the background color. If the -T svg or -T cgm option is
used, an output file without a background may be produced by
setting the background color to "none".
Set the size of the font initially used for rendering text, as a
fraction of the width of the graphics display, to be size. The
default is 0.0525.
Set the font initially used for text to be name. Font names are
case-insensitive. If the specified font is not available, the
default font will be used. Which fonts are available, and the
default font, depend on which -T option is specified (see
above). A list of available fonts can be obtained with the
--help-fonts option (see below).
Set the initial width of lines, as a fraction of the width of
the display, to be line_width. A negative value means that a
default value should be used. This value is format-dependent.
The interpretation of zero line width is also format-dependent
(in some output formats, a zero-width line is the thinnest line
that can be drawn; in others, a zero-width line is invisible).
Set the initial pen color to be name. An unrecognized name sets
the pen color to the default, which is "black".
Options for Metafile Output
The following option is relevant only if the -T option is omitted or if
-T meta is used. In this case the output of plot, like the input, will
be in GNU graphics metafile format.
Output the portable (human-readable) version of GNU metafile
format, rather than the binary version (the default). The
format of the binary version is machine-dependent.
Options for Backward Compatibility
By default, plot assumes that its input file(s) are in either the
binary version or the portable version of GNU metafile format. You may
specify that the input is, instead, in the traditional Unix (pre-GNU)
graphics metafile format, which is documented in plot(5). The
traditional graphics metafile format was produced by pre-GNU versions
Input file(s) are assumed to be in the binary, `high byte first'
version of traditional metafile format. This variant is
Input file(s) are assumed to be in the binary, `low byte first'
version of traditional metafile format. This variant is the
Input file(s) are assumed to be in the ASCII (human-readable)
variant of traditional metafile format. On some older Unix
systems, this variant was produced by plottoa(1).
--help Print a list of command-line options, and exit.
Print a table of available fonts, and exit. The table will
depend on which output format is specified with the -T option.
plot -T X, plot -T svg, plot -T ai, plot -T ps, plot -T cgm, and
plot -T fig each support the 35 standard Postscript fonts. plot
-T svg, plot -T pcl, and plot -T hpgl support the 45 standard
PCL 5 fonts, and the latter two support a number of
Hewlett-Packard vector fonts. All seven support a set of 22
Hershey vector fonts, as do plot -T png, plot -T pnm, plot -T
gif, plot -T regis, and plot -T tek. plot without a -T option
in principle supports any of these fonts, since its output must
be translated to other formats by a further invocation of plot.
The plotfont(1) utility may be used to obtain a character map of
any supported font.
Like --help-fonts, but lists the fonts in a single column to
facilitate piping to other programs. If no output format is
specified with the -T option, the full set of supported fonts is
Print the version number of plot and the plotting utilities
package, and exit.
The environment variables BITMAPSIZE, PAGESIZE, BG_COLOR,
EMULATE_COLOR, MAX_LINE_LENGTH and ROTATION serve as backups for the
options --bitmap-size, --page-size, --bg-color, --emulate-color,
--max-line-length, and --rotation, respectively. The remaining
environment variables are specific to individual output formats.
plot -T X, which pops up a window on an X Window System display and
draws graphics in it, checks the DISPLAY environment variable. Its
value determines the display that will be used.
plot -T png and plot -T gif, which produce output in PNG format and
pseudo-GIF format respectively, are affected by the INTERLACE
environment variable. If its value is "yes", the output will be
interlaced. Also, if the TRANSPARENT_COLOR environment variable is set
to the name of a color, that color will be treated as transparent in
plot -T pnm, which produces output in portable anymap (PBM/PGM/PPM)
format, is affected by the PNM_PORTABLE environment variable. If its
value is "yes", the output will be in a human-readable format rather
than binary (the default).
plot -T cgm, which produces output in CGM (Computer Graphics Metafile)
format, is affected by the CGM_MAX_VERSION and CGM_ENCODING environment
variables. By default, it produces a binary-encoded version of CGM
version 3 format. For backward compatibility, the version number may
be reduced by setting CGM_MAX_VERSION to "2" or "1". Irrespective of
version, the output CGM file will use the human-readable clear text
encoding if CGM_ENCODING is set to "clear_text". However, only binary-
encoded CGM files conform to the WebCGM profile.
plot -T pcl, which produces PCL 5 output for Hewlett-Packard printers
and plotters, is affected by the environment variable
PCL_ASSIGN_COLORS. It should be set to "yes" when producing PCL 5
output for a color printer or other color device. This will ensure
accurate color reproduction by giving the output device complete
freedom in assigning colors, internally, to its "logical pens". If it
is "no" then the device will use a fixed set of colored pens, and will
emulate other colors by shading. The default is "no" because
monochrome PCL 5 devices, which are much more common than colored ones,
must use shading to emulate color.
plot -T hpgl, which produces Hewlett-Packard Graphics Language output,
is affected by several environment variables. The most important is
HPGL_VERSION, which may be set to "1", "1.5", or "2" (the default).
"1" means that the output should be generic HP-GL, "1.5" means that the
output should be suitable for the HP7550A graphics plotter and the
HP758x, HP7595A and HP7596A drafting plotters (HP-GL with some HP-GL/2
extensions), and "2" means that the output should be modern HP-GL/2.
If the version is "1" or "1.5" then the only available fonts will be
vector fonts, and all lines will be drawn with a default width (the -W
option will not work). Additionally, if the version is "1" then the
filling of arbitrary curves with solid color will not be supported
(circles and rectangles aligned with the coordinate axes may be filled,
The position of the plot -T hpgl graphics display on the page can be
rotated 90 degrees counterclockwise by setting the HPGL_ROTATE
environment variable to "yes". This is not the same as the rotation
obtained with the --rotation option, since it both rotates the graphics
display and repositions its lower left corner toward another corner of
the page. Besides "no" and "yes", recognized values for HPGL_ROTATE
are "0", "90", "180", and "270". "no" and "yes" are equivalent to "0"
and "90", respectively. "180" and "270" are supported only if
HPGL_VERSION is "2" (the default).
By default, plot -T hpgl will draw with a fixed set of pens. Which
pens are present may be specified by setting the HPGL_PENS environment
variable. If HPGL_VERSION is "1", the default value of HPGL_PENS is
"1=black"; if HPGL_VERSION is "1.5" or "2", the default value of
HPGL_PENS is "1=black:2=red:3=green:4=yellow:5=blue:6=magenta:7=cyan".
The format should be self-explanatory. By setting HPGL_PENS you may
specify a color for any pen in the range #1...#31. All color names
recognized by the X Window System may be used. Pen #1 must always be
present, though it need not be black. Any other pen in the range
#1...#31 may be omitted.
If HPGL_VERSION is "2" then plot -T hpgl will also be affected by the
environment variable HPGL_ASSIGN_COLORS. If its value is "yes", then
plot -T hpgl will not be restricted to the palette specified in
HPGL_PENS: it will assign colors to "logical pens" in the range
#1...#31, as needed. The default value is "no" because other than
color LaserJet printers and DesignJet plotters, not many HP-GL/2
devices allow the assignment of colors to logical pens.
Opaque filling and the drawing of visible white lines are supported
only if HPGL_VERSION is "2" and the environment variable
HPGL_OPAQUE_MODE is "yes" (the default). If its value is "no" then
white lines (if any), which are normally drawn with pen #0, will not be
drawn. This feature is to accommodate older HP-GL/2 devices. HP-GL/2
pen plotters, for example, do not support opacity or the use of pen #0
to draw visible white lines. Some older HP-GL/2 devices may, in fact,
malfunction if asked to draw opaque objects.
plot -T tek, which produces output for a Tektronix terminal or
emulator, checks the TERM environment variable. If the value of TERM
is a string beginning with "xterm", "nxterm", or "kterm", it is taken
as a sign that plot is running in an X Window System VT100 terminal
emulator: a copy of xterm(1), nxterm(1), or kterm(1). Before drawing
graphics, plot -T tek will emit an escape sequence that causes the
terminal emulator's auxiliary Tektronix window, which is normally
hidden, to pop up. After the graphics are drawn, an escape sequence
that returns control to the original VT100 window will be emitted. The
Tektronix window will remain on the screen.
If the value of TERM is a string beginning with "kermit", "ansi.sys",
or "nansi.sys", it is taken as a sign that plot is running in the VT100
terminal emulator provided by the MS-DOS version of kermit(1). Before
drawing graphics, plot -T tek will emit an escape sequence that
switches the terminal emulator to Tektronix mode. Also, some of the
Tektronix control codes emitted by plot -T tek will be kermit-specific.
There will be a limited amount of color support, which is not normally
the case (the 16 `ansi.sys' colors will be supported). After drawing
graphics, plot -T tek will emit an escape sequence that returns the
emulator to VT100 mode. The key sequence `ALT minus' can be employed
manually within kermit to switch between the two modes.
graph(1), pic2plot(1), tek2plot(1), plotfont(1), plot(3), plot(5), and
"The GNU Plotting Utilities Manual".
plot was written by Robert S. Maier (email@example.com).
Email bug reports to firstname.lastname@example.org.