* Call the formbuilder hook for the edit page.

[ikiwiki] / IkiWiki / Plugin / tex.pm

#!/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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