#### 4.1.24 gpic

The ‘gpic‘ terminal driver generates GPIC graphs in the Free Software Foundations’s "groff" package. The default size is 5 x 3 inches. The only option is the origin, which defaults to (0,0).

Syntax:

          set terminal gpic {<x> <y>}

where ‘x‘ and ‘y‘ are in inches.

A simple graph can be formatted using

          groff -p -mpic -Tps file.pic > file.ps.

The output from pic can be pipe-lined into eqn, so it is possible to put complex functions in a graph with the ‘set label‘ and ‘set {x/y}label‘ commands. For instance,

          set ylab '@space 0 int from 0 to x alpha ( t ) roman d t@'

will label the y axis with a nice integral if formatted with the command:

          gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-package] -Tps
              > filename.ps

Figures made this way can be scaled to fit into a document. The pic language is easy to understand, so the graphs can be edited by hand if need be. All co-ordinates in the pic-file produced by ‘gnuplot‘ are given as x+gnuplotx and y+gnuploty. By default x and y are given the value 0. If this line is removed with an editor in a number of files, one can put several graphs in one figure like this (default size is 5.0x3.0 inches):

          .PS 8.0
          x=0;y=3
          copy "figa.pic"
          x=5;y=3
          copy "figb.pic"
          x=0;y=0
          copy "figc.pic"
          x=5;y=0
          copy "figd.pic"
          .PE

This will produce an 8-inch-wide figure with four graphs in two rows on top of each other.

One can also achieve the same thing by the command

          set terminal gpic x y

for example, using

          .PS 6.0
          copy "trig.pic"
          .PE"