user tabs MDL-17472 Fixed a regression where the $secondrow variable of forum posts...
[moodle.git] / filter / tex / filter.php
CommitLineData
c49dede8 1<?PHP
2/////////////////////////////////////////////////////////////////////////////
3// //
4// NOTICE OF COPYRIGHT //
5// //
6// Moodle - Filter for converting TeX expressions to cached gif images //
7// //
8// Copyright (C) 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu //
9// Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca//
10// This program is free software; you can redistribute it and/or modify //
11// it under the terms of the GNU General Public License as published by //
12// the Free Software Foundation; either version 2 of the License, or //
13// (at your option) any later version. //
14// //
15// This program is distributed in the hope that it will be useful, //
16// but WITHOUT ANY WARRANTY; without even the implied warranty of //
17// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
18// GNU General Public License for more details: //
19// //
20// http://www.gnu.org/copyleft/gpl.html //
21// //
22/////////////////////////////////////////////////////////////////////////////
23//-------------------------------------------------------------------------
24// NOTE: This Moodle text filter converts TeX expressions delimited
25// by either $$...$$ or by <tex...>...</tex> tags to gif images using
26// mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by
220a90c5 27// John Forkosh john@forkosh.com. Several binaries of this areincluded with
28// this distribution.
c49dede8 29// Note that there may be patent restrictions on the production of gif images
30// in Canada and some parts of Western Europe and Japan until July 2004.
31//-------------------------------------------------------------------------
4da85078 32/////////////////////////////////////////////////////////////////////////////
33// To activate this filter, add a line like this to your //
34// list of filters in your Filter configuration: //
35// //
36// filter/tex/filter.php //
37/////////////////////////////////////////////////////////////////////////////
c49dede8 38
f5ceb06a 39function string_file_picture_tex($imagefile, $tex= "", $height="", $width="", $align="middle", $alt='') {
40 if($alt==='') {
41 $alt=s($tex);
42 }
43// Given the path to a picture file in a course, or a URL,
9d49b430 44 // this function includes the picture in the page.
45 global $CFG;
c49dede8 46
9d49b430 47 $output = "";
2bbaf749 48 $origtex = $tex;
0f13ec8f 49 $style = 'style="border:0px; vertical-align:'.$align.';';
9d49b430 50 if ($tex) {
51 $tex = str_replace('&','&amp;',$tex);
52 $tex = str_replace('<','&lt;',$tex);
53 $tex = str_replace('>','&gt;',$tex);
54 $tex = str_replace('"','&quot;',$tex);
55 $tex = str_replace("\'",'&#39;',$tex);
f5ceb06a 56 // Note that we retain the title tag as TeX format rather than using
57 // the alt text, even if supplied. The alt text is intended for blind
58 // users (to provide a text equivalent to the equation) while the title
59 // is there as a convenience for sighted users who want to see the TeX
60 // code.
9d49b430 61 $title = "title=\"$tex\"";
62 }
63 if ($height) {
0f13ec8f 64 $style .= " height:{$height}px;";
9d49b430 65 }
66 if ($width) {
0f13ec8f 67 $style .= " width:{$width}px;";
9d49b430 68 }
0f13ec8f 69 $style .= '"';
9d49b430 70 if ($imagefile) {
09ee7b0d 71 if (!file_exists("$CFG->dataroot/filter/tex/$imagefile") && has_capability('moodle/site:config', get_context_instance(CONTEXT_SYSTEM))) {
220a90c5 72 $output .= "<a href=\"$CFG->wwwroot/filter/tex/texdebug.php\">";
d633b4eb 73 } else {
30fc04e4 74 $output .= "<a target=\"popup\" title=\"TeX\" href=";
220a90c5 75 $output .= "\"$CFG->wwwroot/filter/tex/displaytex.php?";
76 $output .= urlencode($tex) . "\" onclick=\"return openpopup('/filter/tex/displaytex.php?";
30fc04e4 77 $output .= urlencode($tex) . "', 'popup', 'menubar=0,location=0,scrollbars,";
78 $output .= "resizable,width=300,height=240', 0);\">";
894ff63f 79 }
f5ceb06a 80 $output .= "<img class=\"texrender\" $title alt=\"$alt\" src=\"";
9d49b430 81 if ($CFG->slasharguments) { // Use this method if possible for better caching
220a90c5 82 $output .= "$CFG->wwwroot/filter/tex/pix.php/$imagefile";
9d49b430 83 } else {
220a90c5 84 $output .= "$CFG->wwwroot/filter/tex/pix.php?file=$imagefile";
9d49b430 85 }
0f13ec8f 86 $output .= "\" $style />";
d633b4eb 87 $output .= "</a>";
c49dede8 88 } else {
9d49b430 89 $output .= "Error: must pass URL or course";
c49dede8 90 }
9d49b430 91 return $output;
c49dede8 92}
93
94function tex_filter ($courseid, $text) {
82a5323c 95 global $CFG, $DB;
c49dede8 96
9d49b430 97 /// Do a quick check using stripos to avoid unnecessary work
82a76d38 98 if (!preg_match('/<tex/i',$text) and !strstr($text,'$$') and !strstr($text,'\\[') and !preg_match('/\[tex/i',$text)) { //added one more tag (dlnsk)
c49dede8 99 return $text;
100 }
c49dede8 101
9d49b430 102# //restrict filtering to forum 130 (Maths Tools on moodle.org)
103# $scriptname = $_SERVER['SCRIPT_NAME'];
104# if (!strstr($scriptname,'/forum/')) {
105# return $text;
106# }
107# if (strstr($scriptname,'post.php')) {
108# $parent = forum_get_post_full($_GET['reply']);
82a5323c 109# $discussion = $DB->get_record("forum_discussions", array("id"=>$parent->discussion));
9d49b430 110# } else if (strstr($scriptname,'discuss.php')) {
82a5323c 111# $discussion = $DB->get_record("forum_discussions", array("id"=>$_GET['d']));
9d49b430 112# } else {
113# return $text;
114# }
115# if ($discussion->forum != 130) {
116# return $text;
117# }
c49dede8 118 $text .= ' ';
119 preg_match_all('/\$(\$\$+?)([^\$])/s',$text,$matches);
120 for ($i=0;$i<count($matches[0]);$i++) {
121 $replacement = str_replace('$','&#x00024;',$matches[1][$i]).$matches[2][$i];
122 $text = str_replace($matches[0][$i],$replacement,$text);
123 }
124
c49dede8 125 // <tex> TeX expression </tex>
f5ceb06a 126 // or <tex alt="My alternative text to be used instead of the TeX form"> TeX expression </tex>
c49dede8 127 // or $$ TeX expression $$
82a76d38 128 // or \[ TeX expression \] // original tag of MathType and TeXaide (dlnsk)
129 // or [tex] TeX expression [/tex] // somtime it's more comfortable than <tex> (dlnsk)
f5ceb06a 130 preg_match_all('/<tex(?:\s+alt=["\'](.*?)["\'])?>(.+?)<\/tex>|\$\$(.+?)\$\$|\\\\\[(.+?)\\\\\]|\\[tex\\](.+?)\\[\/tex\\]/is', $text, $matches);
c49dede8 131 for ($i=0; $i<count($matches[0]); $i++) {
f5ceb06a 132 $texexp = $matches[2][$i] . $matches[3][$i] . $matches[4][$i] . $matches[5][$i];
133 $alt = $matches[1][$i];
ea3cf781 134 $texexp = str_replace('<nolink>','',$texexp);
135 $texexp = str_replace('</nolink>','',$texexp);
ee9ff7f3 136 $texexp = str_replace('<span class="nolink">','',$texexp);
137 $texexp = str_replace('</span>','',$texexp);
25d7779c 138 $texexp = eregi_replace("<br[[:space:]]*\/?>", '', $texexp); //dlnsk
f352814a 139 $align = "middle";
140 if (preg_match('/^align=bottom /',$texexp)) {
141 $align = "text-bottom";
142 $texexp = preg_replace('/^align=bottom /','',$texexp);
143 } else if (preg_match('/^align=top /',$texexp)) {
144 $align = "text-top";
145 $texexp = preg_replace('/^align=top /','',$texexp);
146 }
9d49b430 147 $md5 = md5($texexp);
82a5323c 148 if (! $texcache = $DB->get_record("cache_filters", array("filter"=>"tex", "md5key"=>$md5))) {
9d49b430 149 $texcache->filter = 'tex';
150 $texcache->version = 1;
151 $texcache->md5key = $md5;
b402e134 152 $texcache->rawtext = $texexp;
9d49b430 153 $texcache->timemodified = time();
82a5323c 154 $DB->insert_record("cache_filters",$texcache, false);
c49dede8 155 }
9d49b430 156 $filename = $md5 . ".gif";
f5ceb06a 157 $text = str_replace( $matches[0][$i], string_file_picture_tex($filename, $texexp, '', '', $align, $alt), $text);
c49dede8 158 }
220a90c5 159 return $text;
9d49b430 160}
c49dede8 161
1cdd857c 162?>