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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/>.
/**
* This filter provides automatic support for MathJax
*
* @package filter_mathjaxloader
* @copyright 2013 Damyon Wiese (damyon@moodle.com)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* Mathjax filtering
*/
class filter_mathjaxloader extends moodle_text_filter {
/*
* Perform a mapping of the moodle language code to the equivalent for MathJax.
*
* @param string $moodlelangcode - The moodle language code - e.g. en_pirate
* @return string The MathJax language code.
*/
public function map_language_code($moodlelangcode) {
$mathjaxlangcodes = array('br',
'cdo',
'cs',
'da',
'de',
'en',
'eo',
'es',
'fa',
'fi',
'fr',
'gl',
'he',
'ia',
'it',
'ja',
'ko',
'lb',
'mk',
'nl',
'oc',
'pl',
'pt',
'pt-br',
'ru',
'sl',
'sv',
'tr',
'uk',
'zh-hans');
$exceptions = array('cz' => 'cs');
// First see if this is an exception.
if (isset($exceptions[$moodlelangcode])) {
$moodlelangcode = $exceptions[$moodlelangcode];
}
// Now look for an exact lang string match.
if (in_array($moodlelangcode, $mathjaxlangcodes)) {
return $moodlelangcode;
}
// Now try shortening the moodle lang string.
$moodlelangcode = preg_replace('/-.*/', '', $moodlelangcode);
// Look for a match on the shortened string.
if (in_array($moodlelangcode, $mathjaxlangcodes)) {
return $moodlelangcode;
}
// All failed - use english.
return 'en';
}
/*
* Add the javascript to enable mathjax processing on this page.
*
* @param moodle_page $page The current page.
* @param context $context The current context.
*/
public function setup($page, $context) {
// This only requires execution once per request.
static $jsinitialised = false;
if (empty($jsinitialised)) {
$url = get_config('filter_mathjaxloader', 'httpsurl');
$lang = $this->map_language_code(current_language());
$url = new moodle_url($url, array('delayStartupUntil' => 'configured'));
$moduleconfig = array(
'name' => 'mathjax',
'fullpath' => $url
);
$page->requires->js_module($moduleconfig);
$config = get_config('filter_mathjaxloader', 'mathjaxconfig');
$params = array('mathjaxconfig' => $config, 'lang' => $lang);
$page->requires->yui_module('moodle-filter_mathjaxloader-loader', 'M.filter_mathjaxloader.configure', array($params));
$jsinitialised = true;
}
}
/*
* This function wraps the filtered text in a span, that mathjaxloader is configured to process.
*
* @param string $text The text to filter.
* @param array $options The filter options.
*/
public function filter($text, array $options = array()) {
global $PAGE;
$legacy = get_config('filter_mathjaxloader', 'texfiltercompatibility');
$extradelimiters = explode(',', get_config('filter_mathjaxloader', 'additionaldelimiters'));
if ($legacy) {
// This replaces any of the tex filter maths delimiters with the default for inline maths in MathJAX "\( blah \)".
// E.g. "<tex.*> blah </tex>".
$text = preg_replace('|<(/?) *tex( [^>]*)?>|u', '[\1tex]', $text);
// E.g. "[tex.*] blah [/tex]".
$text = str_replace('[tex]', '\\(', $text);
$text = str_replace('[/tex]', '\\)', $text);
// E.g. "$$ blah $$".
$text = preg_replace('|\$\$([\S\s]*?)\$\$|u', '\\(\1\\)', $text);
// E.g. "\[ blah \]".
$text = str_replace('\\[', '\\(', $text);
$text = str_replace('\\]', '\\)', $text);
}
$hasinline = strpos($text, '\\(') !== false && strpos($text, '\\)') !== false;
$hasdisplay = (strpos($text, '$$') !== false) ||
(strpos($text, '\\[') !== false && strpos($text, '\\]') !== false);
$hasextra = false;
foreach ($extradelimiters as $extra) {
if ($extra && strpos($text, $extra) !== false) {
$hasextra = true;
break;
}
}
if ($hasinline || $hasdisplay || $hasextra) {
$PAGE->requires->yui_module('moodle-filter_mathjaxloader-loader', 'M.filter_mathjaxloader.typeset');
if ($hasextra) {
// If custom dilimeters are used, wrap whole text to prevent autolinking.
$text = '<span class="nolink">' . $text . '</span>';
} else {
if ($hasinline) {
// If the default inline TeX delimiters \( \) are present, wrap each pair in nolink.
$text = preg_replace('/\\\\\\([\S\s]*?\\\\\\)/u',
'<span class="nolink">\0</span>', $text);
}
if ($hasdisplay) {
// If default display TeX is used, wrap $$ $$ or \[ \] individually.
$text = preg_replace('/\$\$[\S\s]*?\$\$|\\\\\\[[\S\s]*?\\\\\\]/u',
'<span class="nolink">\0</span>', $text);
}
}
return '<span class="filter_mathjaxloader_equation">' . $text . '</span>';
}
return $text;
}
}