68 lines
2.5 KiB
HTML
68 lines
2.5 KiB
HTML
<!-- Creator : groff version 1.24.1 -->
|
|
<!-- CreationDate: Mon Mar 16 21:28:01 2026 -->
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
|
|
"http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<head>
|
|
<meta name="generator" content="groff -Thtml, see www.gnu.org">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
|
|
<meta name="Content-Style" content="text/css">
|
|
<style type="text/css">
|
|
p { margin-top: 0; margin-bottom: 0; vertical-align: top }
|
|
pre { margin-top: 0; margin-bottom: 0; vertical-align: top }
|
|
table { margin-top: 0; margin-bottom: 0; vertical-align: top }
|
|
h1 { text-align: center }
|
|
</style>
|
|
<title>pic-2.html</title>
|
|
|
|
</head>
|
|
<hr>
|
|
[ <a href="pic-1.html">prev</a> | <a href="pic-3.html">next</a> | <a href="pic.html">top</a> ]
|
|
<hr>
|
|
|
|
|
|
<h2>2. Invoking PIC
|
|
<a name="2. Invoking PIC"></a>
|
|
</h2>
|
|
|
|
|
|
<p style="margin-top: 1em">Every <b>pic</b> description is
|
|
a little program describing drawing actions. The
|
|
<b>[gtn]roff</b>-dependent versions compile the program by
|
|
<i>pic</i>(1) into <i>gtroff</i>(1) macros; the
|
|
<i>pic2plot</i>(1) implementation uses a plotting library to
|
|
draw the picture directly. Programs that process or display
|
|
<i>gtroff</i>(1) output need not know or care that parts of
|
|
the image began life as <b>pic</b> descriptions.</p>
|
|
|
|
<p style="margin-top: 1em">The <i>pic</i>(1) program tries
|
|
to translate anything between <b>.PS</b> and <b>.PE</b>
|
|
markers, and passes through everything else. The normal
|
|
definitions of <b>.PS</b> and <b>.PE</b> in the <i>ms</i>
|
|
macro package and elsewhere have also the side-effect of
|
|
centering the <b>pic</b> output on the page.</p>
|
|
|
|
<h3>2.1. PIC Error Messages
|
|
<a name="2.1. PIC Error Messages"></a>
|
|
</h3>
|
|
|
|
|
|
<p style="margin-top: 1em">If you make a mistake in
|
|
<b>pic</b> input such that the program cannot interpret what
|
|
you mean, <i>gpic</i>(1) issues a diagnostic message in the
|
|
format prescribed by the GNU Coding Standards. A typical
|
|
error message looks like</p>
|
|
|
|
|
|
<p style="margin-left:9%; margin-top: 1em">pic:<i>file</i>:<i>nnn</i>:
|
|
syntax error before '<i>token</i>' <br>
|
|
pic:<i>file</i>:<i>nnn</i>: giving up on this picture</p>
|
|
|
|
<p style="margin-top: 1em">where <i>file</i> is the name of
|
|
the file being processed, <i>nnn</i> is a line number within
|
|
that file, and <i>token</i> is a symbol in the <b>pic</b>
|
|
language (often a keyword) near (usually just after) the
|
|
error location.</p>
|
|
<hr>
|
|
[ <a href="pic-1.html">prev</a> | <a href="pic-3.html">next</a> | <a href="pic.html">top</a> ]
|
|
<hr>
|