. /** * 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 ... 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 .= "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', get_context_instance(CONTEXT_SYSTEM))) { $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, $DB; /// Do a quick check using stripos to avoid unnecessary wor if (!preg_match('/get_record("forum_discussions",array("id"=>$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 some algebraic input expression // or @@ some algebraic input expression @@ preg_match_all('/(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches); for ($i=0; $i','',$algebra); $algebra = str_replace('','',$algebra); $algebra = str_replace('','',$algebra); $algebra = str_replace('','',$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],"Syntax error: " . $texexp,$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); $texexp = str_replace('\mbox', '', $texexp); // now blacklisted in tex, sorry $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],"Undetermined error: ",$text); } } else { $text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texcache->rawtext), $text); } } return $text; } }