filter/mathjaxloader/filter.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * This filter provides automatic support for MathJax
  19  *
  20  * @package    filter_mathjaxloader
  21  * @copyright  2013 Damyon Wiese (damyon@moodle.com)
  22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die();
  26
  27 /**
  28  * Mathjax filtering
  29  */
  30 class filter_mathjaxloader extends moodle_text_filter {
  31
  32     /*
  33      * Perform a mapping of the moodle language code to the equivalent for MathJax.
  34      *
  35      * @param string $moodlelangcode - The moodle language code - e.g. en_pirate
  36      * @return string The MathJax language code.
  37      */
  38     public function map_language_code($moodlelangcode) {
  39         $mathjaxlangcodes = array('br',
  40                                   'cdo',
  41                                   'cs',
  42                                   'da',
  43                                   'de',
  44                                   'en',
  45                                   'eo',
  46                                   'es',
  47                                   'fa',
  48                                   'fi',
  49                                   'fr',
  50                                   'gl',
  51                                   'he',
  52                                   'ia',
  53                                   'it',
  54                                   'ja',
  55                                   'ko',
  56                                   'lb',
  57                                   'mk',
  58                                   'nl',
  59                                   'oc',
  60                                   'pl',
  61                                   'pt',
  62                                   'pt-br',
  63                                   'ru',
  64                                   'sl',
  65                                   'sv',
  66                                   'tr',
  67                                   'uk',
  68                                   'zh-hans');
  69         $exceptions = array('cz' => 'cs');
  70
  71         // First see if this is an exception.
  72         if (isset($exceptions[$moodlelangcode])) {
  73             $moodlelangcode = $exceptions[$moodlelangcode];
  74         }
  75
  76         // Now look for an exact lang string match.
  77         if (in_array($moodlelangcode, $mathjaxlangcodes)) {
  78             return $moodlelangcode;
  79         }
  80
  81         // Now try shortening the moodle lang string.
  82         $moodlelangcode = preg_replace('/-.*/', '', $moodlelangcode);
  83         // Look for a match on the shortened string.
  84         if (in_array($moodlelangcode, $mathjaxlangcodes)) {
  85             return $moodlelangcode;
  86         }
  87         // All failed - use english.
  88         return 'en';
  89     }
  90
  91     /*
  92      * Add the javascript to enable mathjax processing on this page.
  93      *
  94      * @param moodle_page $page The current page.
  95      * @param context $context The current context.
  96      */
  97     public function setup($page, $context) {
  98         // This only requires execution once per request.
  99         static $jsinitialised = false;
 100
 101         if (empty($jsinitialised)) {
 102             if (is_https()) {
 103                 $url = get_config('filter_mathjaxloader', 'httpsurl');
 104             } else {
 105                 $url = get_config('filter_mathjaxloader', 'httpurl');
 106             }
 107             $lang = $this->map_language_code(current_language());
 108             $url = new moodle_url($url, array('delayStartupUntil' => 'configured'));
 109
 110             $moduleconfig = array(
 111                 'name' => 'mathjax',
 112                 'fullpath' => $url
 113             );
 114
 115             $page->requires->js_module($moduleconfig);
 116
 117             $config = get_config('filter_mathjaxloader', 'mathjaxconfig');
 118
 119             $params = array('mathjaxconfig' => $config, 'lang' => $lang);
 120
 121             $page->requires->yui_module('moodle-filter_mathjaxloader-loader', 'M.filter_mathjaxloader.configure', array($params));
 122
 123             $jsinitialised = true;
 124         }
 125     }
 126
 127     /*
 128      * This function wraps the filtered text in a span, that mathjaxloader is configured to process.
 129      *
 130      * @param string $text The text to filter.
 131      * @param array $options The filter options.
 132      */
 133     public function filter($text, array $options = array()) {
 134         global $PAGE;
 135
 136         $legacy = get_config('filter_mathjaxloader', 'texfiltercompatibility');
 137         $extradelimiters = explode(',', get_config('filter_mathjaxloader', 'additionaldelimiters'));
 138         if ($legacy) {
 139             // This replaces any of the tex filter maths delimiters with the default for inline maths in MathJAX "\( blah \)".
 140             // E.g. "<tex.*> blah </tex>".
 141             $text = preg_replace('|<(/?) *tex( [^>]*)?>|u', '[\1tex]', $text);
 142             // E.g. "[tex.*] blah [/tex]".
 143             $text = str_replace('[tex]', '\\(', $text);
 144             $text = str_replace('[/tex]', '\\)', $text);
 145             // E.g. "$$ blah $$".
 146             $text = preg_replace('|\$\$([\S\s]*?)\$\$|u', '\\(\1\\)', $text);
 147             // E.g. "\[ blah \]".
 148             $text = str_replace('\\[', '\\(', $text);
 149             $text = str_replace('\\]', '\\)', $text);
 150         }
 151
 152         $hasinline = strpos($text, '\\(') !== false && strpos($text, '\\)') !== false;
 153         $hasdisplay = (strpos($text, '$$') !== false) ||
 154                       (strpos($text, '\\[') !== false && strpos($text, '\\]') !== false);
 155
 156         $hasextra = false;
 157
 158         foreach ($extradelimiters as $extra) {
 159             if ($extra && strpos($text, $extra) !== false) {
 160                 $hasextra = true;
 161                 break;
 162             }
 163         }
 164         if ($hasinline || $hasdisplay || $hasextra) {
 165             $PAGE->requires->yui_module('moodle-filter_mathjaxloader-loader', 'M.filter_mathjaxloader.typeset');
 166             return '<span class="nolink"><span class="filter_mathjaxloader_equation">' . $text . '</span></span>';
 167         }
 168         return $text;
 169     }
 170 }