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#!/usr/bin/perl
# Licensed under GPL v2 or greater
# (c) 2007 Patrick Winnertz <patrick.winnertz@skolelinux.org>
package IkiWiki::Plugin::tex;
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 => "tex", 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 $code) {
return "[[tex ".gettext("missing tex code"). "]]";
}
if (check($code)) {
return create($code, check_height($height), \%params);
}
else {
return "[[tex ".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 ($$$) { #{{{
# This function calls the image generating function and returns
# the <img .. /> for the generated image.
my $code = shift;
my $height = shift;
my $params = shift;
if (! defined($height) and not length($height) ) {
$height = 12;
}
my $digest = md5_hex($code, $height);
my $teximgdir = "/teximages";
my $imglink = "$teximgdir/$digest.png";
my $imglog = "$teximgdir/$digest.log";
will_render($params->{destpage}, $imglink);
will_render($params->{destpage}, $imglog);
my $imgurl;
my $logurl;
if (! $params->{preview}) {
$imgurl = urlto($imglink, $params->{destpage});
$logurl = urlto($imglog, $params->{destpage});
}
else {
$imgurl="$config{url}/$teximgdir/$digest.png";
$logurl="$config{url}/$teximgdir/$digest.log";
}
if (-e "$config{destdir}/$imglink" ||
gen_image($code, $height, $digest, $teximgdir)) {
return qq{<img src="$imgurl" alt="}.uri_escape($code).qq{" class="teximage" />};
}
else {
return qq{[[tex <a href="$logurl">}.gettext("failed to generate image from code")."</a>]]";
}
} #}}}
sub gen_image ($$$$) { #{{{
# Actually creates the image.
my $code = shift;
my $height = shift;
my $digest = shift;
my $imagedir = shift;
#TODO This should move into the setup file.
my $tex = '\documentclass['.$height.'pt]{scrartcl}';
$tex .= '\usepackage[version=3]{mhchem}';
$tex .= '\usepackage{amsmath}';
$tex .= '\usepackage{amsfonts}';
$tex .= '\usepackage{amssymb}';
$tex .= '\pagestyle{empty}';
$tex .= '\begin{document}';
$tex .= '$$'.$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;
} #}}}
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