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- #!/bin/sh
- #
- # eqn2graph -- compile EQN equation descriptions to bitmap images
- #
- # by Eric S. Raymond <esr@thyrsus.com>, July 2002
- #
- # In Unixland, the magic is in knowing what to string together...
- #
- # Take an eqn equation on stdin, emit cropped bitmap on stdout.
- # The pic markup should *not* be wrapped in .EQ/.EN, this script will do that.
- # A -U option on the command line enables gpic/groff "unsafe" mode.
- # A -format FOO option changes the image output format to any format
- # supported by convert(1). All other options are passed to convert(1).
- # The default format is PNG.
- #
- # This is separate from pic2graph because pic processing has some weird
- # clipping effect on the output, mangling equations that are very wide
- # or deep. Besides, this tool can supply its own delimiters.
- #
-
- # Requires the groff suite and the ImageMagick tools. Both are open source.
- # This code is released to the public domain.
- #
- # Here are the assumptions behind the option processing:
- #
- # 1. None of the options of eqn(1) are relevant.
- #
- # 2. Only the -U option of groff(1) is relevant.
- #
- # 3. Many options of convert(1) are potentially relevant, (especially
- # -density, -interlace, -transparency, -border, and -comment).
- #
- # Thus, we pass -U to groff(1), and everything else to convert(1).
- #
- # $Id: eqn2graph.sh,v 1.3 2003/10/28 07:46:23 wlemb Exp $
- #
- groff_opts=""
- convert_opts=""
- format="png"
-
- while [ "$1" ]
- do
- case $1 in
- -unsafe)
- groff_opts="-U";;
- -format)
- format=$2
- shift;;
- -v | --version)
- echo "GNU eqn2graph (groff) version 1.19.1"
- exit 0;;
- --help)
- echo "usage: eqn2graph [ option ...] < in > out"
- exit 0;;
- *)
- convert_opts="$convert_opts $1";;
- esac
- shift
- done
-
- # create temporary directory
- tmp=
- for d in "$GROFF_TMPDIR" "$TMPDIR" "$TMP" "$TEMP" /tmp; do
- test -z "$d" && continue
-
- tmp=`(umask 077 && mktemp -d -q "$d/eqn2graph-XXXXXX") 2> /dev/null` \
- && test -n "$tmp" && test -d "$tmp" \
- && break
-
- tmp=$d/eqn2graph$$-$RANDOM
- (umask 077 && mkdir $tmp) 2> /dev/null && break
- done;
- if test -z "$tmp"; then
- echo "$0: cannot create temporary directory" >&2
- { (exit 1); exit 1; }
- fi
-
- trap 'exit_status=$?; rm -rf $tmp && exit $exit_status' 0 2 15
-
- # Here goes:
- # 1. Add .EQ/.EN.
- # 2. Process through eqn(1) to emit troff markup.
- # 3. Process through groff(1) to emit Postscript.
- # 4. Use convert(1) to crop the Postscript and turn it into a bitmap.
- read equation
- (echo ".EQ"; echo 'delim $$'; echo ".EN"; echo '$'"$equation"'$') | \
- groff -e $groff_opts -Tps -P-pletter > $tmp/eqn2graph.ps \
- && convert -crop 0x0 $convert_opts $tmp/eqn2graph.ps $tmp/eqn2graph.$format \
- && cat $tmp/eqn2graph.$format
-
- # End
-