pic2graph - convert a PIC diagram into a cropped image
pic2graph [ -unsafe ] [ -format fmt ] [ -eqn delim ]
Reads a PIC program as input; produces an image file (by default in Portable Network Graphics format) suitable for the Web as output. Also translates eqn(1) constructs, so it can be used for generating images of mathematical formulae.
PIC is a rather expressive graphics minilanguage suitable for producing box-and-arrow diagrams of the kind frequently used in technical papers and textbooks. The language is sufficiently flexible to be quite useful for state charts, Petri-net diagrams, flow charts, simple circuit schematics, jumper layouts, and other kinds of illustration involving repetitive uses of simple geometric forms and splines. Because PIC descriptions are procedural and object-based, they are both compact and easy to modify.
The PIC language is fully documented in Making Pictures With GNU PIC, a document which is part of the groff(1) distribution.
Your input PIC code should not be wrapped with the .PS and .PE macros that normally guard it within groff(1) macros.
The output image will be clipped to the smallest possible bounding box that contains all the black pixels. Older versions of convert(1) will produce a black-on-white graphic; newer ones may produce a black-on-transparent graphic. By specifying command-line options to be passed to convert(1) you can give it a border, force the background transparent, set the image's pixel density, or perform other useful transformations.
This program uses pic(1), eqn(1), groff(1), gs(1), and the ImageMagick convert(1) program. These programs must be installed on your system and accessible on your $PATH for pic2graph to work.
Run pic(1) and groff(1) in the ’unsafe’ mode enabling the PIC macro sh to execute arbitrary commands. The default is to forbid this.
Specify an output format; the default is PNG (Portable Network Graphics). Any format that convert(1) can emit is supported.
Change the fencepost characters that delimit eqn(1) directives ($ and $, by default). This option requires an argument, but an empty string is accepted as a directive to disable eqn(1) processing.
Command-line switches and arguments not listed above are passed to convert(1).
The eqn(1) initialization file.
The directory in which temporary files will be created. If this is not set pic2graph searches the environment variables TMPDIR, TMP, and TEMP (in that order). Otherwise, temporary files will be created in /tmp.
Due to changes in the behavior of ImageMagick convert(1) that are both forward and backward-incompatible, mismatches between your pic2graph and convert(1) versions may produce zero-sized or untrimmed output images. For this version of pic2graph you will need a version of convert(1) that supports the -trim option; older versions of pic2graph used -crop 0x0, which no longer has trimming behavior.
eqn2graph(1), grap2graph(1), pic(1), eqn(1), groff(1), gs(1), convert(1).
This documentation is released to the public domain.
Eric S. Raymond
, based on a recipe by W. Richard Stevens.