1/**
2 * A plugin which enables rendering of math equations inside
3 * of reveal.js slides. Essentially a thin wrapper for MathJax.
4 *
5 * @author Hakim El Hattab
6 */
7var RevealMath = window.RevealMath || (function(){
8
9	var options = Reveal.getConfig().math || {};
10	var mathjax = options.mathjax || 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js';
11	var config = options.config || 'TeX-AMS_HTML-full';
12	var url = mathjax + '?config=' + config;
13
14	var defaultOptions = {
15		messageStyle: 'none',
16		tex2jax: {
17			inlineMath: [ [ '$', '$' ], [ '\\(', '\\)' ] ],
18			skipTags: [ 'script', 'noscript', 'style', 'textarea', 'pre' ]
19		},
20		skipStartupTypeset: true
21	};
22
23	function defaults( options, defaultOptions ) {
24
25		for ( var i in defaultOptions ) {
26			if ( !options.hasOwnProperty( i ) ) {
27				options[i] = defaultOptions[i];
28			}
29		}
30
31	}
32
33	function loadScript( url, callback ) {
34
35		var head = document.querySelector( 'head' );
36		var script = document.createElement( 'script' );
37		script.type = 'text/javascript';
38		script.src = url;
39
40		// Wrapper for callback to make sure it only fires once
41		var finish = function() {
42			if( typeof callback === 'function' ) {
43				callback.call();
44				callback = null;
45			}
46		}
47
48		script.onload = finish;
49
50		// IE
51		script.onreadystatechange = function() {
52			if ( this.readyState === 'loaded' ) {
53				finish();
54			}
55		}
56
57		// Normal browsers
58		head.appendChild( script );
59
60	}
61
62	return {
63		init: function() {
64
65			defaults( options, defaultOptions );
66			defaults( options.tex2jax, defaultOptions.tex2jax );
67			options.mathjax = options.config = null;
68
69			loadScript( url, function() {
70
71				MathJax.Hub.Config( options );
72
73				// Typeset followed by an immediate reveal.js layout since
74				// the typesetting process could affect slide height
75				MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub ] );
76				MathJax.Hub.Queue( Reveal.layout );
77
78				// Reprocess equations in slides when they turn visible
79				Reveal.addEventListener( 'slidechanged', function( event ) {
80
81					MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, event.currentSlide ] );
82
83				} );
84
85			} );
86
87		}
88	}
89
90})();
91
92Reveal.registerPlugin( 'math', RevealMath );
93