.TH PLOT 1 "Jun 2000" "FSF" "GNU Plotting Utilities"
.SH NAME
plot \- translate GNU metafiles to other graphics formats
.ig
Not all man macros define SB (and not all whatis parsers stop on .\")
..
.de SB
\&\fB\s-1\&\\$1 \\$2\s0\fR
..
.SH SYNOPSIS
.B plot 
[ 
.I options 
] [ 
.I files 
]
.SH DESCRIPTION
.LP
.B 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
.BR graph (1),
.BR pic2plot (1),
.BR tek2plot (1),
and
.BR plotfont (1),
and is further documented in
.BR plot (5),
since it is an enhanced version of the traditional
.BR plot (5)
format found on non-GNU systems.
It can also be produced by the GNU libplot 2-D graphics export library (see
.BR plot (3)).
.LP
The output format is specified with the 
.BR \-T " option."
The possible output formats and display types are the same as those 
supported by
.BR graph (1),
.BR plotfont (1),
.BR pic2plot (1),
and
.BR tek2plot (1).
If an output file is produced, it is written to standard output.
.LP
Options and file names may be interspersed on the command line, but
the options are processed before the file names are read.
If 
.B \-\- 
is seen, it is interpreted as the end of the options.
If no file names are specified, or the file name 
.B \- 
is encountered, the standard input is read.
.SH OPTIONS
.SS General Options
.TP
.BI \-T " type"
.br
.ns
.TP
.BI \-\-output\-format " type"
Select 
.I 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
.BR idraw (1),
CGM format (by default, confirming to the WebCGM profile),
the format used by the 
.BR 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
.BR dxterm (1)
terminal emulator or by a VT330 or VT340 terminal),
Tektronix format (which can be displayed by the
.BR xterm (1)
terminal emulator),
and device-independent GNU metafile format itself.
Unless \fItype\fP\^ is "X", an output file is produced and written
to standard output.
.IP ""
Omitting the 
.B \-T
option is equivalent to specifying
.BR "\-T meta" .
Translating from metafile format to itself is occasionally useful, since
there are two versions of metafile format (see the
.B \-O
option below).
.IP ""
A listing of the fonts available in any specified output format may be
obtained with the
.B \-\-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", and "meta".
.TP
.BI \-p " n"
.br
.ns
.TP
.BI \-\-page\-number " n"
Output only page number 
.IR n ,
within the metafile or sequence of metafiles that is being translated.
.IP ""
Metafiles may consist of one or more pages, numbered beginning with 1.
Also, each page may contain multiple `frames'.
.BR "plot \-T X" ,
.BR "plot \-T regis" ,
and
.BR "plot \-T tek" ,
which plot in real time, will separate
successive frames by screen erasures.
.BR "plot \-T png" ,
.BR "plot \-T pnm" ,
.BR "plot \-T gif" ,
.BR "plot \-T svg" ,
.BR "plot \-T ai" ,
.BR "plot \-T ps" ,
.BR "plot \-T cgm" ,
.BR "plot \-T fig" ,
.BR "plot \-T pcl" ,
and
.BR "plot \-T hpgl" ,
which do not plot in real time, will output only the last frame of any
multi-frame page.
.IP ""
The default behavior, if \fB\-p\fP is not used, is to output all pages.
For example, \fBplot \-T X\fP displays each page in its own X window.
If the 
.BR "\-T png" ,
.BR "\-T pnm" ,
.BR "\-T gif" ,
.BR "\-T ai" ,
or
.B \-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 of
graphics.
.IP ""
Metafiles produced by
.BR graph (1)
and
.BR 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
graphics.
.TP
.B \-s
.br
.ns
.TP
.B \-\-merge\-pages
Merge all displayed pages into a single page, and also merge all `frames'.
.IP ""
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
.BR graph (1).
.TP
.BI \-\-bitmap\-size " bitmap_size"
Set the size of the graphics display in which the plot will be drawn,
in terms of pixels, to be
.IR bitmap_size .
The default is "570x570".
This is relevant only to 
.BR "plot \-T X" , 
.BR "plot \-T png" , 
.BR "plot \-T pnm" , 
and
.BR "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 
.BR "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".
.IP ""
The environment variable 
.SB BITMAPSIZE
can equally well be used to specify the window size.
For backward compatibility, the X resource 
.B Xplot.geometry
may be used instead.
.TP
.BI \-\-emulate\-color " option"
If 
.I option
is 
.IR yes ,
replace each color in the output by an appropriate shade of gray.  This is
seldom useful, except when using
.B 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
.SB EMULATE_COLOR
to "yes".
.TP
.BI \-\-max\-line\-length " max_line_length"
Set the maximum number of points that a
polygonal line may contain, before it is flushed out, to be 
.IR 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 \fImax_line_length\fP\^ is 500.
.IP ""
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 
.SB MAX_LINE_LENGTH
can also be used to specify the maximum line length.
.TP
.BI \-\-page\-size " pagesize"
Set the size of the page on which the plot will be positioned.
This is relevant only to
.BR "plot \-T svg" ,
.BR "plot \-T ai" ,
.BR "plot \-T ps" ,
.BR "plot \-T cgm" ,
.BR "plot \-T fig" ,
.BR "plot \-T pcl" ,
and
.BR "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
.SB PAGESIZE 
can equally well be used to specify the page size.
.IP ""
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
.BR "plot \-T hpgl" , 
the graphics display will, by default, be centered on the page.  
For all of the above except
.B "plot \-T svg"
and
.BR "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.
.TP
.BI \-\-rotation " angle"
Rotate the graphics display by
.IR angle " degrees."
Recognized values are "0", "90", "180", and "270".
"no" and "yes" are equivalent to "0" and "90", respectively.
The environment variable 
.SB ROTATION
can also be used to specify a rotation angle.
.SS "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)
.BR plot (5)
format, which did not support such directives.
.TP
.BI \-\-bg\-color " name"
Set the color initially used for the background to be
.IR name .
This is relevant only to 
.BR "plot \-T X" ,
.BR "plot \-T png" ,
.BR "plot \-T pnm" ,
.BR "plot \-T gif" ,
.BR "plot \-T svg" ,
.BR "plot \-T cgm" ,
and
.BR "plot \-T regis" .
An unrecognized name sets the color to the default, which is "white".
The environment variable
.SB BG_COLOR
can equally well be used to specify the background color.
.IP ""
If the 
.B \-T png
or
.B \-T gif
option is used, a transparent PNG file
or a transparent pseudo-GIF, respectively, may be produced by
setting the 
.SB TRANSPARENT_COLOR
environment variable to the name of the background color.
If the 
.B \-T svg
or
.B \-T cgm
option is used, an output file without a background may be produced
by setting the background color to "none".
.TP
.BI \-f " size"
.br
.ns
.TP
.BI \-\-font\-size " size"
Set the size of the font initially used for rendering text, as a fraction
of the width of the graphics display, to be
.IR size .
The default is 0.0525.
.TP
.BI \-F " name"
.br
.ns
.TP
.BI \-\-font\-name " name"
Set the font initially used for text to be
.IR 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 \fB\-T\fP
option is specified (see above).
A list of available fonts can be obtained with the
.B \-\-help\-fonts
option (see below).
.TP
.BI \-W " line_width"
.br
.ns
.TP
.BI \-\-line\-width " line_width"
Set the initial width of lines, as a fraction of the width of the display,
to be
.IR 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).
.TP
.BI \-\-pen\-color " name"
Set the initial pen color to be
.IR name .
An unrecognized name sets the pen color to the default, which is "black".
.SS Options for Metafile Output
.LP
The following option is relevant only if the
.B \-T
option is omitted or if 
.B "\-T meta"
is used.
In this case the output of
.BR plot ,
like the input, will be in GNU graphics metafile format.
.TP
.B \-O
.br
.ns
.TP
.B \-\-portable\-output
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.
.SS Options for Backward Compatibility
By default, \fBplot\fP 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
.BR plot (5).
The traditional graphics metafile format was produced by 
pre-GNU versions of
.BR graph (1).
.TP
.B \-h
.br
.ns
.TP
.B \-\-high\-byte\-first\-input
Input file(s) are assumed to be in the binary, `high byte first' version
of traditional metafile format.
This variant is uncommon.
.TP
.B \-l
.br
.ns
.TP
.B \-\-low\-byte\-first\-input
Input file(s) are assumed to be in the binary, `low byte first' version 
of traditional metafile format.
This variant is the most common.
.TP
.B \-A
.br
.ns
.TP
.B \-\-ascii\-input
Input file(s) are assumed to be in the 
.SM ASCII
(human-readable) variant of traditional metafile format.
On some older Unix systems, this variant was produced by
.BR plottoa (1).
.SS Informational Options
.TP 
.B \-\-help
Print a list of command-line options, and exit.
.TP
.B \-\-help\-fonts
Print a table of available fonts, and exit.
The table will depend on which output format
is specified with the 
.B \-T 
option.
.BR "plot \-T X" ,
.BR "plot \-T svg" ,
.BR "plot \-T ai" ,
.BR "plot \-T ps" ,
.BR "plot \-T cgm" ,
and 
.B plot \-T fig
each support the 35 standard Postscript fonts.
.BR "plot \-T svg" ,
.BR "plot \-T pcl" ,
and 
.B 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
.BR "plot \-T png" ,
.BR "plot \-T pnm" ,
.BR "plot \-T gif" ,
.BR "plot \-T regis" ,
and
.BR "plot \-T tek" .
.B plot
without a
.B \-T
option in principle
supports any of these fonts, since its output must be translated
to other formats by a further invocation of
.BR plot .
.IP ""
The
.BR plotfont (1)
utility may be used to obtain a character map of any supported font.
.TP
.B \-\-list\-fonts
Like 
.BR \-\-help\-fonts , 
but lists the fonts in a single column to facilitate piping to other
programs.
If no output format is specified with the
.B \-T
option, the full set of supported fonts is listed.
.TP
.B \-\-version
Print the version number of 
.B plot
and the plotting utilities package, and exit.
.SH "ENVIRONMENT"
The environment variables 
.SB BITMAPSIZE,
.SB PAGESIZE,
.SB BG_COLOR,
.SB EMULATE_COLOR,
.SB MAX_LINE_LENGTH
and
.SB ROTATION
serve as backups for the options 
.BR \-\-bitmap\-size , 
.BR \-\-page\-size ,
.BR \-\-bg\-color , 
.BR \-\-emulate\-color , 
.BR \-\-max\-line\-length ,
and
.BR \-\-rotation ,
respectively.
The remaining environment variables are specific to individual output formats.
.LP
.BR "plot \-T X" ,
which pops up a window on an X Window System
display and draws graphics in it, checks the 
.SB DISPLAY
environment variable.
Its value determines the display that will be used.
.LP
.BR "plot \-T png"
and
.BR "plot \-T gif" ,
which produce output in PNG format and pseudo-GIF format respectively,
are affected by the 
.SB INTERLACE
environment variable.
If its value is "yes", the output will be interlaced.
Also, if the 
.SB TRANSPARENT_COLOR
environment variable is set to the name of a color, that color will
be treated as transparent in the output.
.LP
.BR "plot \-T pnm" ,
which produces output in portable anymap (PBM/PGM/PPM) format,
is affected by the 
.SB PNM_PORTABLE
environment variable.
If its value is "yes", the output will be in a human-readable format
rather than binary (the default).
.LP
.BR "plot \-T cgm" ,
which produces output in CGM (Computer Graphics Metafile) format,
is affected by the 
.SB CGM_MAX_VERSION
and
.SB 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
.SB CGM_MAX_VERSION
to "2" or "1".
Irrespective of version, the output CGM file will use the human-readable
clear text encoding if 
.SB CGM_ENCODING
is set to "clear_text".
However, only binary-encoded CGM files conform to the WebCGM profile.
.LP
.BR "plot \-T pcl" ,
which produces PCL 5 output for Hewlett\-Packard
printers and plotters, is affected by the environment variable
.SB 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.
.LP
.BR "plot \-T hpgl" ,
which produces Hewlett\-Packard Graphics Language
output, is affected by several environment variables.
The most important is 
.SB 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
.B \-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, though).
.LP
The position of the 
.B plot \-T hpgl
graphics display on the page
can be rotated 90 degrees counterclockwise by setting the
.SB HPGL_ROTATE
environment variable to "yes".
This is not the same as the rotation obtained with the 
.B \-\-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 
.SB 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 
.SB HPGL_VERSION
is "2" (the default).
.LP
By default, 
.B plot \-T hpgl
will draw with a fixed set of pens.
Which pens are present may be specified by setting the
.SB HPGL_PENS
environment variable.
If
.SB HPGL_VERSION
is "1", the default value of
.SB HPGL_PENS
is "1=black"; if
.SB HPGL_VERSION
is "1.5" or "2", the default value of 
.SB 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
.SB 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.
.LP
If
.SB HPGL_VERSION
is "2" then 
.B plot \-T hpgl
will also be
affected by the environment variable 
.SB HPGL_ASSIGN_COLORS.
If its value is "yes", then 
.B plot \-T hpgl
will not be restricted to the palette specified in 
.SB 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.
.LP
Opaque filling and the drawing of visible white lines are supported
only if
.SB HPGL_VERSION
is "2" and the environment variable 
.SB 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.
.LP
.BR "plot \-T tek" ,
which produces output for a Tektronix terminal or emulator, checks the
.SB TERM
environment variable.
If the value of
.SB TERM
is a string beginning with "xterm", "nxterm", or "kterm", it is taken as a
sign that
.B plot
is running in an X Window System VT100 terminal emulator: a copy of
.BR xterm (1),
.BR nxterm (1),
or
.BR kterm (1).
Before drawing graphics,
.B 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.
.LP
If the value of
.SB TERM
is a string beginning with
"kermit", "ansi.sys", or "nansi.sys", it is
taken as a sign that 
.B plot
is running in the VT100 terminal emulator provided by the MS-DOS version of
.BR kermit (1).
Before drawing graphics, \fBplot \-T tek\fP will emit an escape sequence
that switches the terminal emulator to Tektronix mode.
Also, some of the Tektronix control codes emitted by 
\fBplot \-T tek\fP will be \fBkermit\fP-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, \fBplot \-T tek\fP will emit an escape sequence
that returns the emulator to VT100 mode.
The key sequence `ALT minus' can be employed manually within \fBkermit\fP
to switch between the two modes.
.SH "SEE ALSO"
.BR graph (1),
.BR pic2plot (1),
.BR tek2plot (1),
.BR plotfont (1),
.BR plot (3),
.BR plot (5),
and "The GNU Plotting Utilities Manual".
.SH AUTHORS
.B plot
was written by Robert S. Maier (\fBrsm@math.arizona.edu\fP).
.SH BUGS
Email bug reports to
.BR bug\-gnu\-utils@gnu.org .