eqn2graph

eqn2graph [files…]

files
    Input files containing eqn; defaults to stdin. Outputs pic to stdout.

eqn2graph is a groff utility that translates mathematical equations in EQN markup language into pic picture language commands. This enables embedding equations as graphical elements within pic diagrams in troff-formatted documents.

It processes input containing mixed text and eqn constructs, converting eqn elements like fractions (&frac{a}{b}), integrals (&int), sums (&sum), square roots (&sqrt{}), superscripts/subscripts, and matrices into pic primitives such as boxes, lines, circles, and positioning commands.

Usage fits into a groff preprocessing pipeline: pipe eqn-enhanced text through eqn2graph to generate pic code, then process with pic, tbl, eqn (for remaining math), and groff or troff for final output (e.g., PostScript, PDF).

Ideal for technical documents needing math integrated into figures, like scientific papers or manuals. Limitations include support only for eqn features mappable to 2D graphics; advanced typesetting like stacked equations may lose fidelity.

Supports subset of eqn constructs graphical in pic; complex layouts (e.g., piled, over/under) may simplify or fail. No options for customization.

echo 'S: circle at 1i right of B
frac {1}{x + sqrt {x^2 + 1}} with .l at S.l' | eqn2graph
Outputs pic code drawing the fraction as boxes/lines.

Use as: eqn input.roff | eqn2graph | pic | groff -Tps > output.ps

Part of GNU groff (GNU roff) since early 1990s, extending AT&T Unix troff tools. Created to bridge eqn and pic preprocessors, absent in original Unix.

eqn(7), pic(1), groff(1), grap(1)