IkiWiki/Plugin/teximg.pm

   1 #!/usr/bin/perl
   2 # Licensed under GPL v2 or greater
   3 # (c) 2007 Patrick Winnertz <patrick.winnertz@skolelinux.org>
   4
   5 package IkiWiki::Plugin::teximg;
   6 use warnings;
   7 use strict;
   8 use Digest::MD5 qw(md5_hex);
   9 use File::Temp qw(tempdir);
  10 use HTML::Entities;
  11 use IkiWiki 2.00;
  12
  13 my $default_prefix = <<EOPREFIX;
  14 \\documentclass{article}
  15 \\usepackage{amsmath}
  16 \\usepackage{amsfonts}
  17 \\usepackage{amssymb}
  18 \\pagestyle{empty}
  19 \\begin{document}
  20 EOPREFIX
  21
  22 my $default_postfix = '\\end{document}';
  23
  24 sub import { #{{{
  25         hook(type => "getsetup", id => "teximg", call => \&getsetup);
  26         hook(type => "preprocess", id => "teximg", call => \&preprocess);
  27 } #}}}
  28
  29 sub getsetup () { #{{{
  30         return
  31                 plugin => {
  32                         safe => 1,
  33                         rebuild => undef,
  34                 },
  35                 teximg_dvipng => {
  36                         type => "boolean",
  37                         description => "Should teximg use dvipng to render, or dvips and convert?",
  38                         safe => 0,
  39                         rebuild => undef,
  40                 },
  41                 teximg_prefix => {
  42                         type => "string",
  43                         example => $default_prefix,
  44                         description => "LaTeX prefix for teximg plugin",
  45                         safe => 0, # Not sure how secure LaTeX is...
  46                         rebuild => 1,
  47                 },
  48                 teximg_postfix => {
  49                         type => "string",
  50                         example => $default_postfix,
  51                         description => "LaTeX postfix for teximg plugin",
  52                         safe => 0, # Not sure how secure LaTeX is...
  53                         rebuild => 1,
  54                 },
  55 } #}}}
  56
  57 sub preprocess (@) { #{{{
  58         my %params = @_;
  59
  60         my $height = $params{height};
  61         if (! defined $height || ! length $height) {
  62                 $height = 12;
  63         }
  64         else {
  65                 $height =~ s#(\d+)#$1#;
  66         }
  67
  68         my $code = $params{code};
  69         if (! defined $code && ! length $code) {
  70                 error gettext("missing tex code");
  71         }
  72
  73         if (check($code)) {
  74                 return create($code, check_height($height), \%params);
  75         }
  76         else {
  77                 error gettext("code includes disallowed latex commands")
  78         }
  79 } #}}}
  80
  81 sub check_height ($) { #{{{
  82         # Since latex doesn't support unlimited scaling this function
  83         # returns the closest supported size.
  84         my $height =shift;
  85
  86         my @allowed=(8,9,10,11,12,14,17,20);
  87
  88         my $ret;
  89         my $fit;
  90         foreach my $val (@allowed) {
  91                 my $f = abs($val - $height);
  92                 if (! defined($fit) || $f < $fit ) {
  93                         $ret=$val;
  94                         $fit=$f;
  95                 }
  96         }
  97         return $ret;
  98 } #}}}
  99
 100 sub create ($$$) { #{{{
 101         # This function calls the image generating function and returns
 102         # the <img .. /> for the generated image.
 103         my $code = shift;
 104         my $height = shift;
 105         my $params = shift;
 106
 107         if (! defined($height) and not length($height) ) {
 108                 $height = 12;
 109         }
 110
 111         my $digest = md5_hex($code, $height);
 112
 113         my $imglink= $params->{page} . "/$digest.png";
 114         my $imglog =  $params->{page} .  "/$digest.log";
 115         will_render($params->{page}, $imglink);
 116         will_render($params->{page}, $imglog);
 117
 118         my $imgurl=urlto($imglink, $params->{destpage});
 119         my $logurl=urlto($imglog, $params->{destpage});
 120
 121         if (-e "$config{destdir}/$imglink" ||
 122             gen_image($code, $height, $digest, $params->{page})) {
 123                 return qq{<img src="$imgurl" alt="}
 124                         .(exists $params->{alt} ? $params->{alt} : encode_entities($code))
 125                         .qq{" class="teximg" />};
 126         }
 127         else {
 128                 error qq{<a href="$logurl">}.gettext("failed to generate image from code")."</a>";
 129         }
 130 } #}}}
 131
 132 sub gen_image ($$$$) { #{{{
 133         # Actually creates the image.
 134         my $code = shift;
 135         my $height = shift;
 136         my $digest = shift;
 137         my $imagedir = shift;
 138
 139         if (!defined $config{teximg_prefix}) {
 140                 $config{teximg_prefix} = $default_prefix;
 141         }
 142         if (!defined $config{teximg_postfix}) {
 143                 $config{teximg_postfix} = $default_postfix;
 144         }
 145         if (!defined $config{teximg_dvipng}) {
 146                 $config{teximg_dvipng} = length `which dvipng 2>/dev/null`;
 147         }
 148
 149         my $tex = $config{teximg_prefix};
 150         $tex .= '$$'.$code.'$$';
 151         $tex .= $config{teximg_postfix};
 152         $tex =~ s!\\documentclass{article}!\\documentclass[${height}pt]{article}!g;
 153         $tex =~ s!\\documentclass{scrartcl}!\\documentclass[${height}pt]{scrartcl}!g;
 154
 155         my $tmp = eval { create_tmp_dir($digest) };
 156         if (! $@ &&
 157             writefile("$digest.tex", $tmp, $tex) &&
 158             system("cd $tmp; latex --interaction=nonstopmode $tmp/$digest.tex > /dev/null") == 0 &&
 159             # ensure destination directory exists
 160             writefile("$imagedir/$digest.png", $config{destdir}, "") &&
 161             (($config{teximg_dvipng} &&
 162                 system("dvipng -D 120 -bg Transparent -T tight -o $config{destdir}/$imagedir/$digest.png $tmp/$digest.dvi > $tmp/$digest.log") == 0
 163             ) || (!$config{teximg_dvipng} &&
 164                 system("dvips -E $tmp/$digest.dvi -o $tmp/$digest.ps 2> $tmp/$digest.log") == 0 &&
 165                 system("convert -density 120  -trim -transparent \"#FFFFFF\" $tmp/$digest.ps $config{destdir}/$imagedir/$digest.png > $tmp/$digest.log") == 0
 166             ))) {
 167                 return 1;
 168         }
 169         else {
 170                 # store failure log
 171                 my $log="";
 172                 {
 173                         if (open(my $f, '<', "$tmp/$digest.log")) {
 174                                 local $/=undef;
 175                                 $log = <$f>;
 176                                 close($f);
 177                         }
 178                 }
 179                 writefile("$digest.log", "$config{destdir}/$imagedir", $log);
 180
 181                 return 0;
 182         }
 183 } #}}}
 184
 185 sub create_tmp_dir ($) { #{{{
 186         # Create a temp directory, it will be removed when ikiwiki exits.
 187         my $base = shift;
 188
 189         my $template = $base.".XXXXXXXXXX";
 190         my $tmpdir = tempdir($template, TMPDIR => 1, CLEANUP => 1);
 191         return $tmpdir;
 192 } #}}}
 193
 194 sub check ($) { #{{{
 195         # Check if the code is ok
 196         my $code = shift;
 197
 198         my @badthings = (
 199                 qr/\$\$/,
 200                 qr/\\include/,
 201                 qr/\\includegraphic/,
 202                 qr/\\usepackage/,
 203                 qr/\\newcommand/,
 204                 qr/\\renewcommand/,
 205                 qr/\\def/,
 206                 qr/\\input/,
 207                 qr/\\open/,
 208                 qr/\\loop/,
 209                 qr/\\errorstopmode/,
 210                 qr/\\scrollmode/,
 211                 qr/\\batchmode/,
 212                 qr/\\read/,
 213                 qr/\\write/,
 214         );
 215
 216         foreach my $thing (@badthings) {
 217                 if ($code =~ m/$thing/ ) {
 218                         return 0;
 219                 }
 220         }
 221         return 1;
 222 } #}}}
 223
 224 1