1 files changed, 108 insertions, 0 deletions
diff --git a/contrib/eqn2graph/eqn2graph.sh b/contrib/eqn2graph/eqn2graph.sh
new file mode 100644
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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 eqn markup should *not* be wrapped in .EQ/.EN, this script will do that.
+# 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. Many options of convert(1) are potentially relevant, (especially
+# -density, -interlace, -transparency, -border, and -comment).
+#
+# Thus, we pass everything except -format to convert(1).
+#
+convert_opts=""
+convert_trim_arg="-trim"
+format="png"
+
+while [ "$1" ]
+do
+    case $1 in
+    -format)
+	format=$2
+	shift;;
+    -v | --version)
+	echo "GNU eqn2graph (groff) version @VERSION@"
+	exit 0;;
+    --help)
+	echo "usage: eqn2graph [ option ...] < in > out"
+	exit 0;;
+    *)
+	convert_opts="$convert_opts $1";;
+    esac
+    shift
+done
+
+# create temporary directory
+tmp=
+for d in "$GROFF_TMPDIR" "$TMPDIR" "$TMP" "$TEMP" /tmp
+do
+    test -n "$d" && break
+done
+
+if ! test -d "$d"
+then
+    echo "$0: error: temporary directory \"$d\" does not exist or is" \
+        "not a directory" >&2
+    exit 1
+fi
+
+if ! tmp=`(umask 077 && mktemp -d -q "$d/eqn2graph-XXXXXX") 2> /dev/null`
+then
+    # mktemp failed--not installed or is a version that doesn't support those
+    # flags?  Fall back to older method which uses more predictable naming.
+    #
+    # $RANDOM is a Bashism.  The fallback of $PPID is not good pseudorandomness,
+    # but is supported by the stripped-down dash shell, for instance.
+    tmp="$d/eqn2graph$$-${RANDOM:-$PPID}"
+    (umask 077 && mkdir "$tmp") 2> /dev/null
+fi
+
+if ! test -d "$tmp"
+then
+    echo "$0: error: cannot create temporary directory \"$tmp\"" >&2
+    exit 1
+fi
+
+# See if the installed version of convert(1) is new enough to support the -trim
+# option.  Versions that didn't were described as "old" as early as 2008.
+is_convert_recent=`convert -help | grep -e -trim`
+if test -z "$is_convert_recent"
+then
+    echo "$0: warning: falling back to old '-crop 0x0' trim method" >&2
+    convert_trim_arg="-crop 0x0"
+fi
+
+trap 'exit_status=$?; rm -rf "$tmp" && exit $exit_status' EXIT INT TERM
+
+# Here goes:
+# 1. Add .EQ/.EN.
+# 2. Process through eqn(1) to emit troff markup.
+# 3. Process through groff(1) to emit Postscript.
+# 4. Use convert(1) to crop the Postscript and turn it into a bitmap.
+read equation
+(echo ".EQ"; echo 'delim $$'; echo ".EN"; echo '$'"$equation"'$') | \
+	groff -e -Tps -P-pletter > "$tmp"/eqn2graph.ps \
+	&& convert $convert_trim_arg $convert_opts "$tmp"/eqn2graph.ps \
+	   "$tmp"/eqn2graph.$format \
+	&& cat "$tmp"/eqn2graph.$format
+
+# End