thepurpleblob
18a2407ef4
be used if it works on the server, otherwise mimetex is used as before. Produces rather nicer images, and the full range of formatting can be used, rather than mimetex's limited set.
154 lines
7.0 KiB
PHP
154 lines
7.0 KiB
PHP
<?PHP
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/////////////////////////////////////////////////////////////////////////////
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// //
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// NOTICE OF COPYRIGHT //
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// //
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// Moodle - Filter for converting TeX expressions to cached gif images //
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// //
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// Copyright (C) 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu //
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// Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca//
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation; either version 2 of the License, or //
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// (at your option) any later version. //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License for more details: //
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// //
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// http://www.gnu.org/copyleft/gpl.html //
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// //
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/////////////////////////////////////////////////////////////////////////////
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//-------------------------------------------------------------------------
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// NOTE: This Moodle text filter converts TeX expressions delimited
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// by either $$...$$ or by <tex...>...</tex> tags to gif images using
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// mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by
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// John Forkosh john@forkosh.com. Several binaries of this areincluded with
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// this distribution.
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// Note that there may be patent restrictions on the production of gif images
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// in Canada and some parts of Western Europe and Japan until July 2004.
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//-------------------------------------------------------------------------
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/////////////////////////////////////////////////////////////////////////////
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// To activate this filter, add a line like this to your //
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// list of filters in your Filter configuration: //
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// //
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// filter/tex/filter.php //
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/////////////////////////////////////////////////////////////////////////////
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$CFG->texfilterdir = "filter/tex";
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function string_file_picture_tex($imagefile, $tex= "", $height="", $width="", $align="middle") {
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// Given the path to a picture file in a course, or a URL,
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// this function includes the picture in the page.
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global $CFG;
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$output = "";
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if ($tex) {
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$tex = str_replace('&','&',$tex);
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$tex = str_replace('<','<',$tex);
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$tex = str_replace('>','>',$tex);
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$tex = str_replace('"','"',$tex);
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$tex = str_replace("\'",''',$tex);
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$title = "title=\"$tex\"";
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}
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if ($height) {
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$height = "height=\"$height\"";
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}
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if ($width) {
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$width = "width=\"$width\"";
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}
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if ($imagefile) {
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if (!file_exists("$CFG->dataroot/$CFG->texfilterdir/$imagefile") && isadmin()) {
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$output .= "<a href=\"$CFG->wwwroot/$CFG->texfilterdir/texdebug.php\">";
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} else {
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$output .= "<a target=\"popup\" title=\"TeX\" href=";
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$output .= "\"$CFG->wwwroot/$CFG->texfilterdir/displaytex.php?";
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$output .= urlencode($tex) . "\" onclick=\"return openpopup('/$CFG->texfilterdir/displaytex.php?";
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$output .= urlencode($tex) . "', 'popup', 'menubar=0,location=0,scrollbars,";
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$output .= "resizable,width=300,height=240', 0);\">";
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}
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$output .= "<img class=\"texrender\" border=\"0\" $title $height $width alt=\"\" src=\"";
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if ($CFG->slasharguments) { // Use this method if possible for better caching
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$output .= "$CFG->wwwroot/$CFG->texfilterdir/pix.php/$imagefile";
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} else {
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$output .= "$CFG->wwwroot/$CFG->texfilterdir/pix.php?file=$imagefile";
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}
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$output .= "\" style=\"vertical-align:$align\" />";
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$output .= "</a>";
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} else {
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$output .= "Error: must pass URL or course";
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}
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return $output;
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}
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function tex_filter ($courseid, $text) {
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global $CFG;
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/// Do a quick check using stripos to avoid unnecessary work
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if (!preg_match('/<tex/i',$text) and !strstr($text,'$$')) {
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return $text;
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}
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# //restrict filtering to forum 130 (Maths Tools on moodle.org)
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# $scriptname = $_SERVER['SCRIPT_NAME'];
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# if (!strstr($scriptname,'/forum/')) {
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# return $text;
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# }
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# if (strstr($scriptname,'post.php')) {
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# $parent = forum_get_post_full($_GET['reply']);
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# $discussion = get_record("forum_discussions","id",$parent->discussion);
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# } else if (strstr($scriptname,'discuss.php')) {
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# $discussion = get_record("forum_discussions","id",$_GET['d'] );
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# } else {
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# return $text;
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# }
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# if ($discussion->forum != 130) {
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# return $text;
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# }
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$text .= ' ';
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preg_match_all('/\$(\$\$+?)([^\$])/s',$text,$matches);
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for ($i=0;$i<count($matches[0]);$i++) {
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$replacement = str_replace('$','$',$matches[1][$i]).$matches[2][$i];
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$text = str_replace($matches[0][$i],$replacement,$text);
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}
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//if (isadmin()) { error_reporting (E_ALL); }; //for debugging
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// <tex> TeX expression </tex>
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// or $$ TeX expression $$
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preg_match_all('/<tex>(.+?)<\/tex>|\$\$(.+?)\$\$/is', $text, $matches);
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for ($i=0; $i<count($matches[0]); $i++) {
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$texexp = $matches[1][$i] . $matches[2][$i];
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$texexp = str_replace('<nolink>','',$texexp);
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$texexp = str_replace('</nolink>','',$texexp);
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$texexp = str_replace('<span class="nolink">','',$texexp);
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$texexp = str_replace('</span>','',$texexp);
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$align = "middle";
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if (preg_match('/^align=bottom /',$texexp)) {
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$align = "text-bottom";
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$texexp = preg_replace('/^align=bottom /','',$texexp);
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} else if (preg_match('/^align=top /',$texexp)) {
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$align = "text-top";
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$texexp = preg_replace('/^align=top /','',$texexp);
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}
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$md5 = md5($texexp);
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if (! $texcache = get_record("cache_filters","filter","tex", "md5key", $md5)) {
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$texcache->filter = 'tex';
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$texcache->version = 1;
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$texcache->md5key = $md5;
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$texcache->rawtext = addslashes($texexp);
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$texcache->timemodified = time();
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insert_record("cache_filters",$texcache, false);
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}
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$filename = $md5 . ".gif";
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$text = str_replace( $matches[0][$i], string_file_picture_tex($filename, $texexp, '', '', $align), $text);
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}
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return $text;
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}
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?>
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