.\" $Id: pic2graph.man,v 1.7 2008/09/29 21:55:15 wl Exp $
.\" This documentation is released to the public domain.
.TH PIC2GRAPH 1 "31 December 2010" "Groff Version 1.21"
.IX pic2graph
.SH NAME
pic2graph \- convert a PIC diagram into a cropped image
.
.
.SH SYNOPSIS
.B pic2graph
[
.B \-unsafe
]
[
.BI \-format\  fmt
]
[
.BI \-eqn\  delim
]
.
.
.SH DESCRIPTION
Reads a PIC program as input; produces an image file (by default in
Portable Network Graphics format) suitable for the Web as output.
Also translates
.BR eqn (1)
constructs, so it can be used for generating images of mathematical
formulae.
.P
PIC is a rather expressive graphics minilanguage suitable for
producing box-and-arrow diagrams of the kind frequently used in
technical papers and textbooks.
The language is sufficiently flexible to be quite useful for state
charts, Petri-net diagrams, flow charts, simple circuit schematics,
jumper layouts, and other kinds of illustration involving repetitive
uses of simple geometric forms and splines.
Because PIC descriptions are procedural and object-based, they are
both compact and easy to modify.
.P
The PIC language is fully documented in
.IR "Making Pictures With GNU PIC" ,
a document which is part of the
.BR groff (1)
distribution.
.P
Your input PIC code should
.I not
be wrapped with the \&.PS and \&.PE macros that normally guard it within
.BR groff (1) 
macros.
.P
The output image will be clipped to the smallest possible bounding box
that contains all the black pixels.
Older versions of
.BR \%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 
.BR \%convert (1)
you can give it a border, force the background transparent, set the
image's pixel density, or perform other useful transformations.
.P
This program uses 
.BR pic (1),
.BR eqn (1),
.BR groff (1),
.BR gs (1),
and the ImageMagick
.BR \%convert (1)
program.
These programs must be installed on your system and accessible on your
$PATH for
.B pic2graph
to work.
.
.
.SH OPTIONS
.TP
.B \-unsafe
Run 
.BR pic (1)
and
.BR groff (1)
in the `unsafe' mode enabling the PIC macro
.B sh
to execute arbitrary commands.
The default is to forbid this.
.TP
.BI \-format\  fmt
Specify an output format; the default is PNG (Portable Network Graphics).
Any format that
.BR \%convert (1)
can emit is supported.
.TP
.BI \-eqn\  delim
Change the fencepost characters that delimit 
.BR eqn (1)
directives
.RB ( $
and
.BR $ ,
by default).
This option requires an argument, but an empty string is
accepted as a directive to disable
.BR eqn (1)
processing.
.PP
Command-line switches and arguments not listed above are passed to
.BR \%convert (1).
.
.
.SH FILES
.TP \w'\fB/usr/share/groff/1.21/tmac/eqnrc'u+2n
.B /usr/share/groff/1.21/tmac/eqnrc
The 
.BR eqn (1)
initialization file.
.
.
.SH ENVIRONMENT
.TP
.B GROFF_TMPDIR
The directory in which temporary files will be created.
If this is not set
.B pic2graph
searches the environment variables
.BR \%TMPDIR ,
.BR TMP ,
and
.B TEMP
(in that order).
Otherwise, temporary files will be created in
.BR /tmp .
.
.
.SH BUGS
Due to changes in the behavior of ImageMagick
.BR \%convert (1)
that are both forward and backward-incompatible,
mismatches between your
.B pic2graph
and 
.BR \%convert (1)
versions may produce zero-sized or untrimmed output images.
For this version of 
.B pic2graph
you will need a version of
.BR \%convert (1)
that supports the
.B \-trim
option; older versions of 
.B pic2graph
used
.BR \-crop\~0x0 ,
which no longer has trimming behavior.
.
.
.SH "SEE ALSO"
.BR eqn2graph (1),
.BR grap2graph (1),
.BR pic (1),
.BR eqn (1),
.BR groff (1),
.BR gs (1),
.BR \%convert (1).
.
.
.SH AUTHOR
Eric S. Raymond <esr@thyrsus.com>, based on a recipe by W. Richard Stevens.
.
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