mirror of
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156 lines
7.4 KiB
PHP
156 lines
7.4 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,'$$') and !strstr($text,'\\[') and !preg_match('/\[tex/i',$text)) { //added one more tag (dlnsk)
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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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// or \[ TeX expression \] // original tag of MathType and TeXaide (dlnsk)
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// or [tex] TeX expression [/tex] // somtime it's more comfortable than <tex> (dlnsk)
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preg_match_all('/<tex>(.+?)<\/tex>|\$\$(.+?)\$\$|\\\\\[(.+?)\\\\\]|\\[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] . $matches[3][$i] . $matches[4][$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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$texexp = eregi_replace("<br[[:space:]]*\/?>", '', $texexp); //dlnsk
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$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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