contrib/eqn2graph/eqn2graph.sh

   1 #! /bin/sh
   2 #
   3 # eqn2graph -- compile EQN equation descriptions to bitmap images
   4 #
   5 # by Eric S. Raymond <esr@thyrsus.com>, July 2002
   6 #
   7 # In Unixland, the magic is in knowing what to string together...
   8 #
   9 # Take an eqn equation on stdin, emit cropped bitmap on stdout.
  10 # The pic markup should *not* be wrapped in .EQ/.EN, this script will do that.
  11 # A -U option on the command line enables gpic/groff "unsafe" mode.
  12 # A -format FOO option changes the image output format to any format
  13 # supported by convert(1).  All other options are passed to convert(1).
  14 # The default format is PNG.
  15 #
  16 # This is separate from pic2graph because pic processing has some weird
  17 # clipping effect on the output, mangling equations that are very wide
  18 # or deep.  Besides, this tool can supply its own delimiters.
  19 #
  20
  21 # Requires the groff suite and the ImageMagick tools.  Both are open source.
  22 # This code is released to the public domain.
  23 #
  24 # Here are the assumptions behind the option processing:
  25 #
  26 # 1. None of the options of eqn(1) are relevant.
  27 #
  28 # 2. Only the -U option of groff(1) is relevant.
  29 #
  30 # 3. Many options of convert(1) are potentially relevant, (especially
  31 # -density, -interlace, -transparency, -border, and -comment).
  32 #
  33 # Thus, we pass -U to groff(1), and everything else to convert(1).
  34 #
  35 # $Id$
  36 #
  37 groff_opts=""
  38 convert_opts=""
  39 format="png"
  40
  41 while [ "$1" ]
  42 do
  43     case $1 in
  44     -unsafe)
  45         groff_opts="-U";;
  46     -format)
  47         format=$2
  48         shift;;
  49     -v | --version)
  50         echo "GNU eqn2graph (groff) version @VERSION@"
  51         exit 0;;
  52     --help)
  53         echo "usage: eqn2graph [ option ...] < in > out"
  54         exit 0;;
  55     *)
  56         convert_opts="$convert_opts $1";;
  57     esac
  58     shift
  59 done
  60
  61 # create temporary directory
  62 tmp=
  63 for d in "$GROFF_TMPDIR" "$TMPDIR" "$TMP" "$TEMP" /tmp; do
  64     test -z "$d" && continue
  65
  66     tmp=`(umask 077 && mktemp -d -q "$d/eqn2graph-XXXXXX") 2> /dev/null` \
  67     && test -n "$tmp" && test -d "$tmp" \
  68     && break
  69
  70     tmp=$d/eqn2graph$$-$RANDOM
  71     (umask 077 && mkdir $tmp) 2> /dev/null && break
  72 done;
  73 if test -z "$tmp"; then
  74     echo "$0: cannot create temporary directory" >&2
  75     { (exit 1); exit 1; }
  76 fi
  77
  78 trap 'exit_status=$?; rm -rf $tmp && exit $exit_status' 0 2 15
  79
  80 # Here goes:
  81 # 1. Add .EQ/.EN.
  82 # 2. Process through eqn(1) to emit troff markup.
  83 # 3. Process through groff(1) to emit Postscript.
  84 # 4. Use convert(1) to crop the Postscript and turn it into a bitmap.
  85 read equation
  86 (echo ".EQ"; echo 'delim $$'; echo ".EN"; echo '$'"$equation"'$') | \
  87         groff -e $groff_opts -Tps -P-pletter > $tmp/eqn2graph.ps \
  88         && convert -trim -crop 0x0 $convert_opts $tmp/eqn2graph.ps $tmp/eqn2graph.$format \
  89         && cat $tmp/eqn2graph.$format
  90
  91 # End