Convert an eqn equation into a cropped image
eqn2graph [ -unsafe ] [ -formatfmt ]
Reads an EQN equation (one line) as input; produces an image file (by default in Portable Network Graphics format) suitable for the Web as output.
Your input EQN code should not have the .EQ/.EN preamble that that normally precedes it within groff(1) macros; nor do you need to have dollar-sign or other delimiters around the equation.
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 eqn(1), groff(1), and the ImageMagick convert(1) program. These programs must be installed on your system and accessible on your $PATH for eqn2graph to work.
-unsafe
Run groff(1) in the `unsafe' mode enabling the PIC macro sh to execute arbitrary commands. The default is to forbid this.
-formatfmt
Specify an output format; the default is PNG (Portable Network Graphics). Any format that convert(1) can emit is supported.
Command-line switches and arguments not listed above are passed to convert(1).
/usr/share/groff/1.22.2/tmac/eqnrc The eqn(1) initialization file.
GROFF_TMPDIR
The directory in which temporary files will be created. If this is not set eqn2graph 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 eqn2graph and convert(1) versions may produce zero-sized or untrimmed output images. For this version of eqn2graph you will need a version of convert(1) that supports the -trim option; older versions of eqn2graph used -crop\~0x0, which no longer has trimming behavior.
pic2graph(1), grap2graph(1), eqn(1), groff(1), gs(1), convert(1).
Eric S. Raymond <[email protected]>.