--- /dev/null
+#!/usr/bin/perl
+# Licensed under GPL v2 or greater
+# (c) 2007 Patrick Winnertz <patrick.winnertz@skolelinux.org>
+
+package IkiWiki::Plugin::teximg;
+use warnings;
+use strict;
+use Digest::MD5 qw(md5_hex);
+use File::Temp qw(tempdir);
+use URI::Escape qw(uri_escape);
+use IkiWiki 2.00;
+
+sub import { #{{{
+ hook(type => "preprocess", id => "teximg", call => \&preprocess);
+} #}}}
+
+sub preprocess (@) { #{{{
+ my %params = @_;
+
+ my $height = $params{height};
+ if (! defined $height || ! length $height) {
+ $height = 12;
+ }
+ else {
+ $height =~ s#(\d+)#$1#;
+ }
+
+ my $code = $params{code};
+ if (! defined $code && ! length $code) {
+ return "[[teximg ".gettext("missing tex code"). "]]";
+ }
+
+ if (check($code)) {
+ return create($code, check_height($height), \%params);
+ }
+ else {
+ return "[[teximg ".gettext("code includes disallowed latex commands"). "]]";
+ }
+} #}}}
+
+sub check_height ($) { #{{{
+ # Since latex doesn't support unlimited scaling this function
+ # returns the closest supported size.
+ my $height =shift;
+
+ my @allowed=(8,9,10,11,12,14,17,20);
+
+ my $ret;
+ my $fit;
+ foreach my $val (@allowed) {
+ my $f = abs($val - $height);
+ if (! defined($fit) || $f < $fit ) {
+ $ret=$val;
+ $fit=$f;
+ }
+ }
+ return $ret;
+} #}}}
+
+sub create ($$$) { #{{{
+ # This function calls the image generating function and returns
+ # the <img .. /> for the generated image.
+ my $code = shift;
+ my $height = shift;
+ my $params = shift;
+
+ if (! defined($height) and not length($height) ) {
+ $height = 12;
+ }
+
+ my $digest = md5_hex($code, $height);
+
+ my $teximgdir = "/teximag";
+ my $imglink = "$teximgdir/$digest.png";
+ my $imglog = "$teximgdir/$digest.log";
+ will_render($params->{destpage}, $imglink);
+ will_render($params->{destpage}, $imglog);
+
+ my $imgurl;
+ my $logurl;
+ if (! $params->{preview}) {
+ $imgurl = urlto($imglink, $params->{destpage});
+ $logurl = urlto($imglog, $params->{destpage});
+ }
+ else {
+ $imgurl="$config{url}/$teximgdir/$digest.png";
+ $logurl="$config{url}/$teximgdir/$digest.log";
+ }
+
+ if (-e "$config{destdir}/$imglink" ||
+ gen_image($code, $height, $digest, $teximgdir)) {
+ return qq{<img src="$imgurl" alt="}
+ .(exists $params{alt} ? $params{alt} : uri_escape($code))
+ .qq{" class="teximg" />};
+ }
+ else {
+ return qq{[[teximg <a href="$logurl">}.gettext("failed to generate image from code")."</a>]]";
+ }
+} #}}}
+
+sub gen_image ($$$$) { #{{{
+ # Actually creates the image.
+ my $code = shift;
+ my $height = shift;
+ my $digest = shift;
+ my $imagedir = shift;
+
+ #TODO This should move into the setup file.
+ my $tex = '\documentclass['.$height.'pt]{scrartcl}';
+ $tex .= '\usepackage[version=3]{mhchem}';
+ $tex .= '\usepackage{amsmath}';
+ $tex .= '\usepackage{amsfonts}';
+ $tex .= '\usepackage{amssymb}';
+ $tex .= '\pagestyle{empty}';
+ $tex .= '\begin{document}';
+ $tex .= '$$'.$code.'$$';
+ $tex .= '\end{document}';
+
+ my $tmp = eval { create_tmp_dir($digest) };
+ if (! $@ &&
+ writefile("$digest.tex", $tmp, $tex) &&
+ system("cd $tmp; latex --interaction=nonstopmode $tmp/$digest.tex > /dev/null") == 0 &&
+ system("dvips -E $tmp/$digest.dvi -o $tmp/$digest.ps 2> $tmp/$digest.log") == 0 &&
+ # ensure destination directory exists
+ writefile("$imagedir/$digest.png", $config{destdir}, "") &&
+ system("convert -density 120 -trim -transparent \"#FFFFFF\" $tmp/$digest.ps $config{destdir}/$imagedir/$digest.png > $tmp/$digest.log") == 0) {
+ return 1;
+ }
+ else {
+ # store failure log
+ my $log;
+ {
+ open(my $f, '<', "$tmp/$digest.log");
+ local $/=undef;
+ $log = <$f>;
+ close($f);
+ }
+ writefile("$digest.log", "$config{destdir}/$imagedir", $log);
+
+ return 0;
+ }
+} #}}}
+
+sub create_tmp_dir ($) { #{{{
+ # Create a temp directory, it will be removed when ikiwiki exits.
+ my $base = shift;
+
+ my $template = $base.".XXXXXXXXXX";
+ my $tmpdir = tempdir($template, TMPDIR => 1, CLEANUP => 1);
+ return $tmpdir;
+} #}}}
+
+sub check ($) { #{{{
+ # Check if the code is ok
+ my $code = shift;
+
+ my @badthings = (
+ qr/\$\$/,
+ qr/\\include/,
+ qr/\\includegraphic/,
+ qr/\\usepackage/,
+ qr/\\newcommand/,
+ qr/\\renewcommand/,
+ qr/\\def/,
+ qr/\\input/,
+ qr/\\open/,
+ qr/\\loop/,
+ qr/\\errorstopmode/,
+ qr/\\scrollmode/,
+ qr/\\batchmode/,
+ qr/\\read/,
+ qr/\\write/,
+ );
+
+ foreach my $thing (@badthings) {
+ if ($code =~ m/$thing/ ) {
+ return 0;
+ }
+ }
+ return 1;
+} #}}}
+
+1