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<?php// This file is part of Moodle - http://moodle.org///// Moodle is free software: you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// Moodle is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with Moodle. If not, see <http://www.gnu.org/licenses/>./*** Moodle - Filter for converting simple calculator-type algebraic* expressions to cached gif images** @package filter* @subpackage algebra* @copyright 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu* Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later*/defined('MOODLE_INTERNAL') || die();//-------------------------------------------------------------------------// NOTE: This Moodle text filter converts algebraic expressions delimited// by either @@...@@ or by <algebra...>...</algebra> tags// first converts it to TeX using WeBWorK algebra parser Perl library// AlgParser.pm, part of the WeBWorK distribution obtained from// http://webhost.math.rochester.edu/downloadwebwork/// then converts the TeX to gif images using// mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by// John Forkosh john@forkosh.com. The mimetex.cgi ELF binary compiled for Linux i386// as well as AlgParser.pm are included with this distribution.// Note that there may be patent restrictions on the production of gif images// in Canada and some parts of Western Europe and Japan until July 2004.//-------------------------------------------------------------------------// You will then need to edit your moodle/config.php to invoke mathml_filter.php//-------------------------------------------------------------------------function filter_algebra_image($imagefile, $tex= "", $height="", $width="", $align="middle") {// Given the path to a picture file in a course, or a URL,// this function includes the picture in the page.global $CFG, $OUTPUT;$output = "";$style = 'style="border:0px; vertical-align:'.$align.';';$title = '';if ($tex) {$tex = html_entity_decode($tex, ENT_QUOTES, 'UTF-8');$title = 'title="'.s($tex).'"';}if ($height) {$style .= " height:{$height}px;";}if ($width) {$style .= " width:{$width}px;";}$style .= '"';$anchorcontents = '';if ($imagefile) {$anchorcontents .= "<img $title alt=\"".s($tex)."\" src=\"";if ($CFG->slasharguments) { // Use this method if possible for better caching$anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php/$imagefile";} else {$anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php?file=$imagefile";}$anchorcontents .= "\" $style />";if (!file_exists("$CFG->dataroot/filter/algebra/$imagefile") && has_capability('moodle/site:config', context_system::instance())) {$link = '/filter/algebra/algebradebug.php';$action = null;} else {$link = new moodle_url('/filter/tex/displaytex.php', array('texexp'=>$tex));$action = new popup_action('click', $link, 'popup', array('width'=>320,'height'=>240)); //TODO: the popups do not work when text caching is enabled!!}$output .= $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX'));} else {$output .= "Error: must pass URL or course";}return $output;}class filter_algebra extends moodle_text_filter {public function filter($text, array $options = array()){global $CFG, $DB;/// Do a quick check using stripos to avoid unnecessary worif (!preg_match('/<algebra/i',$text) && !strstr($text,'@@')) {return $text;}//restrict filtering to forum 130 (Maths Tools on moodle.org)# $scriptname = $_SERVER['SCRIPT_NAME'];# if (!strstr($scriptname,'/forum/')) {# return $text;# }# if (strstr($scriptname,'post.php')) {# $parent = forum_get_post_full($_GET['reply']);# $discussion = $DB->get_record("forum_discussions",array("id"=>$parent->discussion));# } else if (strstr($scriptname,'discuss.php')) {# $discussion = $DB->get_record("forum_discussions",array("id"=>$_GET['d']));# } else {# return $text;# }# if ($discussion->forum != 130) {# return $text;# }preg_match_all('/@(@@+)([^@])/',$text,$matches);for ($i=0;$i<count($matches[0]);$i++) {$replacement = str_replace('@','@',$matches[1][$i]).$matches[2][$i];$text = str_replace($matches[0][$i],$replacement,$text);}// <algebra> some algebraic input expression </algebra>// or @@ some algebraic input expression @@preg_match_all('/<algebra>(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches);for ($i=0; $i<count($matches[0]); $i++) {$algebra = $matches[1][$i] . $matches[2][$i];// Look for some common false positives, and skip processing them.if ($algebra == 'PLUGINFILE' || $algebra == 'DRAFTFILE') {// Raw pluginfile URL.continue;}if (preg_match('/^ -\d+(,\d+)? \+\d+(,\d+)? $/', $algebra)) {// Part of a unified diff.continue;}$algebra = str_replace('<nolink>','',$algebra);$algebra = str_replace('</nolink>','',$algebra);$algebra = str_replace('<span class="nolink">','',$algebra);$algebra = str_replace('</span>','',$algebra);$align = "middle";if (preg_match('/^align=bottom /',$algebra)) {$align = "text-bottom";$algebra = preg_replace('/^align=bottom /','',$algebra);} else if (preg_match('/^align=top /',$algebra)) {$align = "text-top";$algebra = preg_replace('/^align=top /','',$algebra);}$md5 = md5($algebra);$filename = $md5 . ".gif";if (! $texcache = $DB->get_record("cache_filters",array("filter"=>"algebra", "md5key"=>$md5))) {$algebra = str_replace('<','<',$algebra);$algebra = str_replace('>','>',$algebra);$algebra = str_replace('<>','#',$algebra);$algebra = str_replace('<=','%',$algebra);$algebra = str_replace('>=','!',$algebra);$algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);$algebra = str_replace('delta','zdelta',$algebra);$algebra = str_replace('beta','bita',$algebra);$algebra = str_replace('theta','thita',$algebra);$algebra = str_replace('zeta','zita',$algebra);$algebra = str_replace('eta','xeta',$algebra);$algebra = str_replace('epsilon','zepslon',$algebra);$algebra = str_replace('upsilon','zupslon',$algebra);$algebra = preg_replace('!\r\n?!',' ',$algebra);$algebra = escapeshellarg($algebra);if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {$cmd = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";} else {$cmd = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";}$texexp = `$cmd`;if (preg_match('/parsehilight/',$texexp)) {$text = str_replace( $matches[0][$i],"<b>Syntax error:</b> " . $texexp,$text);} else if ($texexp) {$texexp = str_replace('zeroplace','',$texexp);$texexp = str_replace('#','\not= ',$texexp);$texexp = str_replace('%','\leq ',$texexp);$texexp = str_replace('!','\geq ',$texexp);$texexp = str_replace('\left{','{',$texexp);$texexp = str_replace('\right}','}',$texexp);$texexp = str_replace('\fun',' ',$texexp);$texexp = str_replace('infty','\infty',$texexp);$texexp = str_replace('alpha','\alpha',$texexp);$texexp = str_replace('gamma','\gamma',$texexp);$texexp = str_replace('iota','\iota',$texexp);$texexp = str_replace('kappa','\kappa',$texexp);$texexp = str_replace('lambda','\lambda',$texexp);$texexp = str_replace('mu','\mu',$texexp);$texexp = str_replace('nu','\nu',$texexp);$texexp = str_replace('xi','\xi',$texexp);$texexp = str_replace('rho','\rho',$texexp);$texexp = str_replace('sigma','\sigma',$texexp);$texexp = str_replace('tau','\tau',$texexp);$texexp = str_replace('phi','\phi',$texexp);$texexp = str_replace('chi','\chi',$texexp);$texexp = str_replace('psi','\psi',$texexp);$texexp = str_replace('omega','\omega',$texexp);$texexp = str_replace('zdelta','\delta',$texexp);$texexp = str_replace('bita','\beta',$texexp);$texexp = str_replace('thita','\theta',$texexp);$texexp = str_replace('zita','\zeta',$texexp);$texexp = str_replace('xeta','\eta',$texexp);$texexp = str_replace('zepslon','\epsilon',$texexp);$texexp = str_replace('zupslon','\upsilon',$texexp);$texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);$texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);$texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);$texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);$texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);$texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);$texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);$texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);$texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);$texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);$texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);$texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);$texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);//$texexp = preg_replace('/\\\frac{(.+?)}{\\\left\((.+?)\\\right\)}/s','\frac{'."\$1}{\$2}",$texexp);$texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);$texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);$texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);$texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);$texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);$texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);$texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);// Remove a forbidden keyword.$texexp = str_replace('\mbox', '', $texexp);$texcache = new stdClass();$texcache->filter = 'algebra';$texcache->version = 1;$texcache->md5key = $md5;$texcache->rawtext = $texexp;$texcache->timemodified = time();$DB->insert_record("cache_filters", $texcache, false);$text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texexp, '', '', $align), $text);} else {$text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> " . $matches[0][$i], $text);}} else {$text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texcache->rawtext), $text);}}return $text;}}