HOW TO USE PIC driver: 


I have tested driver under gnuplot3.2, and I am currently using it
with the reengineered troff, groff, which is distributed by Free
Software Foundation, but it should work for AT&T's DWB as well. As
gpic can produce TeX output, it could possibly be an alternative to
the LaTeX driver for TeX-users having the tpic macros (see the gpic
man page - I don't know much about TeX so please don't ask me about
this).

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 lable 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 coordinates 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 i 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 inches wide figure with four graphs in two rows
on top of each other

One can also achieve the same thing by the command
 
set term pic x y

For example, using

.PS 6.0
copy "trig.pic"
.PE

the following session generated a two by two figure with
four graphs:


	G N U P L O T
	unix version 3.2 
	patchlevel 2, Mar 24 92
	last modified Sat Mar 24 21:08:47 PST 1992

Copyright(C) 1986, 1987, 1990, 1991, 1992  Thomas Williams, Colin Kelley

	Send bugs and comments to bug-gnuplot@ames.arc.nasa.gov

Terminal type set to 'x11'
gnuplot> set out 'trig.pic'
gnuplot> set ter pic 0 5
Terminal type set to 'pic'
Options are 'Pic's origin is at (0.000000,5.000000)'
gnuplot> plot sin(x)
gnuplot> set ter pic 5 5
Terminal type set to 'pic'
Options are 'Pic's origin is at (5.000000,5.000000)'
gnuplot> plot cos(x)
gnuplot> set ter pic 0 0
set ter pic 0 0
Terminal type set to 'pic'
Options are 'Pic's origin is at (0.000000,0.000000)'
gnuplot> plot tan(x)
gnuplot> set ter pic 5 0
Terminal type set to 'pic'
Options are 'Pic's origin is at (5.000000,0.000000)'
gnuplot> plot cos(x)/sin(x)
plot cos(x)/sin(x)
gnuplot> quit



Scaling can be done using set size.


I prefer this way of including graphs to using encapsulated in troff
documents, because of the possiblity to preprocess with eqn, and
because pic is much easier to understand than postscript  - at least for me.


WHAT HAS TO BE DONE TO IMPROVE THIS DRIVER

1.) Nice markers

2.) Dot-dashed line styles

3.) Possibly make line thickness an option when set term pic

4.) Making it possible to select fonts for both pic and eqn from
    gnuplot's command line.


I am happy to share this piece of software with anyone, in the hope
that it will be useful for at least someone. But taking into account
that it is the very first version of the driver, I would be happy if I
could get into contact with people able to help me improve it.

Mind you: Anything thats free comes with no guarantee!

Good Luck

Sigfrid Lundberg (siglun@volterra.teorekol.lu.se)