Add MathJax and mhchem support to Mahara (bug #1464858)

This provides support for rendering LaTeX into math
& chemistry equations.

Change-Id: I34a30296f46ba7eeb635e6924172ddc6e65175c3
Signed-off-by: Aaron Wells <aaronw@catalyst.net.nz>

htdocs/admin/site/options.php

@@ -712,6 +712,14 @@ $siteoptionform = array(
                     'help'         => true,
                     'disabled'     => in_array('wysiwyg', $OVERRIDDEN),
                 ),
+                'mathjax' => array(
+                    'type'         => 'switchbox',
+                    'title'        => get_string('mathjax', 'admin'),
+                    'description'  => get_string('mathjaxdescription', 'admin'),
+                    'defaultvalue' => get_config('mathjax'),
+                    'help'         => true,
+                    'disabled'     => in_array('mathjax', $OVERRIDDEN),
+                ),
                 'sitefilesaccess' => array(
                     'type'         => 'switchbox',
                     'title'        => get_string('sitefilesaccess', 'admin'),
@@ -784,7 +792,7 @@ function siteoptions_submit(Pieform $form, $values) {
         'sitename','lang','theme', 'dropdownmenu',
         'defaultaccountlifetime', 'defaultregistrationexpirylifetime', 'defaultaccountinactiveexpire', 'defaultaccountinactivewarn',
         'defaultaccountlifetimeupdate', 'allowpublicviews', 'allowpublicprofiles', 'allowanonymouspages', 'generatesitemap',
-        'registration_sendweeklyupdates', 'institutionexpirynotification', 'institutionautosuspend', 'requireregistrationconfirm',
+        'registration_sendweeklyupdates', 'mathjax', 'institutionexpirynotification', 'institutionautosuspend', 'requireregistrationconfirm',
         'showselfsearchsideblock', 'nousernames', 'searchplugin', 'showtagssideblock',
         'tagssideblockmaxtags', 'country', 'viewmicroheaders', 'userscanchooseviewthemes',
         'remoteavatars', 'userscanhiderealnames', 'antispam', 'spamhaus', 'surbl', 'anonymouscomments',

htdocs/js/views.js

@@ -1042,6 +1042,9 @@
         if (!config['handheld_device'] && tinyMCE && tinyMCE.activeEditor && tinyMCE.activeEditor.id) {
             tinyMCE.execCommand('mceRemoveEditor', false, tinyMCE.activeEditor.id);
         }
+        if (config.mathjax && MathJax !== undefined) {
+            MathJax.Hub.Queue(["Typeset", MathJax.Hub]);
+        }
         workspace.find('.mediaplayer-container').each(function() {
             $(this).css({'height': ''});
             $('mediaplayer:first', this).show();

htdocs/lang/en.utf8/admin.php

@@ -458,6 +458,9 @@ $string['watchlistdelaydescription'] = 'The delay in minutes between sending ema
 $string['watchlistdelaytitle'] = 'Watchlist notification delay';
 $string['defaultmultipleblogs'] = 'Multiple journals';
 $string['defaultmultipleblogsdescription1'] = 'Allow users to have multiple journals by default. Users can override this in their account settings page.';
+$string['mathjax'] = 'Enable MathJax';
+$string['mathjaxdescription'] = 'MathJax renders LaTeX markup into properly formatted math and science equations, on portfolio pages.';
+$string['mathjaxconfig'] = 'MathJax configuration';
 
 // Site content
 $string['about']               = 'About';

htdocs/lang/en.utf8/help/forms/siteoptions.mathjax.html

+<!-- @license http://www.gnu.org/copyleft/gpl.html GNU GPL version 3 or later -->
+<!-- @copyright For copyright information on Mahara, please see the README file distributed with this software. -->
+<h3>MathJax</h3> 
+MathJax is a JavaScript display engine for TeX, LaTeX, AsciiMath and MathMl notation which allows mathematics and science equations to be displayed in Mahara pages.
+<p>MathJax allows the display of equations throughout your Mahara installation.</p>
+<h4>MathJax URL</h4>
+<p>The default configuration uses the latest stable version on the MathJax Content Distribution Network (CDN). http and https protocols may be used, as appopriate.</p>
+<p>Alternatively, $cfg->mathjaxpath may use a local server installation of MathJax. See <a href="http://docs.mathjax.org/en/latest/installation.html">http://docs.mathjax.org/en/latest/installation.html</a></p>
+<p>The default includes a commonly used configuration allowing input of MathML, AsciiMath, TeX or LaTeX and processing to MathML or HTML-CSS</p>
+<h4>MathJax additional configuration</h4>
+<p>Additional MathJax configuration can be added to $cfg->mathjaxconfig. The default MathJax configuration should be appropriate for most users, but MathJax is highly configurable and any of the standard MathJax configuration options can be added here.</p>
+<p>By default, includes the mhchem extension which adds the \ce macro for chemical formulae. See <a href="http://docs.mathjax.org/en/latest/tex.html#tex-and-latex-extensions">http://docs.mathjax.org/en/latest/tex.html#tex-and-latex-extensions</a>.</p>

htdocs/lib/config-defaults.php

@@ -633,3 +633,21 @@ $cfg->showloginsideblock = true;
  * experience.
  */
 $cfg->ajaxifyblocks = true;
+
+/**
+ * @global string $cfg->mathjaxpath Determines the path to CDN or server-local installation of MathJax.js.
+ * If MathJax is enabled, use to configure path to MathJax.
+ */
+$cfg->mathjaxpath = '//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML&delayStartupUntil=configured';
+
+/**
+ * @global string $cfg->mathjaxconfig Determines MathJax configuration options.
+ * The default MathJax configuration should be appropriate for most users, but MathJax is highly configurable
+ * and any of the standard MathJax configuration options can be added here.
+ */
+$cfg->mathjaxconfig = '
+MathJax.Hub.Config({
+  TeX:{extensions: ["mhchem.js"]}
+});
+MathJax.Hub.Configured();
+';

htdocs/lib/web.php

@@ -202,6 +202,11 @@ function smarty($javascript = array(), $headers = array(), $pagestrings = array(
     $javascript_array[] = $jsroot . 'jquery/deprecated_jquery.js';
     $headers[] = '<script type="application/javascript">$j=jQuery;</script>';
 
+    // If necessary, load MathJax configuration
+    if (get_config('mathjax')) {
+        $headers[] = '<script type="application/javascript">'.get_config('mathjaxconfig').'</script>';
+    }
+
     // TinyMCE must be included first for some reason we're not sure about
     //
     // Note: we do not display tinyMCE for mobile devices
@@ -399,6 +404,11 @@ EOF;
     }
     $javascript_array[] = $jsroot . 'keyboardNavigation.js';
 
+    //If necessary, load MathJax path
+    if (get_config('mathjax')) {
+        $javascript_array[] = get_config('mathjaxpath');
+    }
+
     $strings = array();
     foreach ($pagestrings as $k => $v) {
         if (is_array($v)) {

htdocs/theme/raw/js/block.js

@@ -21,6 +21,9 @@ jQuery(function($) {
                     if ($(this).is(':empty')){
                         $(this).closest('.panel').addClass('hidden');
                     }
+                    if (config.mathjax && MathJax !== undefined) {
+                        MathJax.Hub.Queue(["Typeset", MathJax.Hub, blocks.get(i)]);
+                    }
                });
 
             }

htdocs/theme/raw/templates/header/head.tpl

@@ -17,7 +17,8 @@
         'userid': {$USER->get('id')},
         'mobile': {if $MOBILE}1{else}0{/if},
         'handheld_device': {if $HANDHELD_DEVICE}1{else}0{/if},
-        'cc_enabled': {$CC_ENABLED|intval}
+        'cc_enabled': {$CC_ENABLED|intval},
+        'mathjax': {ifconfig key=mathjax}1{else}0{/ifconfig}
     {literal}}{/literal};
     </script>
     {$STRINGJS|safe}