PLOT

Section: GNU Plotting Utilities (1)
Updated: Jun 2000
Page Index

NAME

plot - translate GNU metafiles to other graphics formats

SYNOPSIS

plot [ options ] [ files ]

DESCRIPTION

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 read.

OPTIONS

General Options

-T type
--output-format type: 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", and "meta".
-p n
--page-number n: 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 multi-frame page.
: 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 of graphics.
: 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 graphics.
-s
--merge-pages: Merge all displayed pages into a single page, and also merge all `frames'.
: 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).
--bitmap-size bitmap_size: 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.
--emulate-color option: 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".
--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 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 length.
--page-size pagesize: 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.
--rotation angle: 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 directives.

--bg-color name: 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".
-f size
--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 size. The default is 0.0525.
-F name
--font-name name: 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).
-W line_width
--line-width line_width: 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).
--pen-color name: 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.

-O
--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.

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 of graph(1).

-h
--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.
-l
--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.
-A
--ascii-input: 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).

Informational Options

--help: Print a list of command-line options, and exit.
--help-fonts: 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.
--list-fonts: 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 listed.
--version: Print the version number of plot and the plotting utilities package, and exit.

ENVIRONMENT

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 the output.

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, though).

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.

AUTHORS

plot was written by Robert S. Maier (rsm@math.arizona.edu).

BUGS

Email bug reports to bug-gnu-utils@gnu.org.