1 ( function( window, document, settings ) {
2 var src, ready, ii, tests;
5 * Create a canvas element for testing native browser support
8 var canvas = document.createElement( 'canvas' );
9 var context = canvas.getContext && canvas.getContext( '2d' );
12 * Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
13 * made of two characters, so some browsers (notably, Firefox OS X) don't support them.
17 * @param type {String} Whether to test for support of "flag" or "emoji4" emoji.
18 * @return {Boolean} True if the browser can render emoji, false if it cannot.
20 function browserSupportsEmoji( type ) {
21 var stringFromCharCode = String.fromCharCode,
22 flag, flag2, technologist, technologist2;
24 if ( ! context || ! context.fillText ) {
28 // Cleanup from previous test.
29 context.clearRect( 0, 0, canvas.width, canvas.height );
32 * Chrome on OS X added native emoji rendering in M41. Unfortunately,
33 * it doesn't work when the font is bolder than 500 weight. So, we
34 * check for bold rendering support to avoid invisible emoji in Chrome.
36 context.textBaseline = 'top';
37 context.font = '600 32px Arial';
42 * This works because the image will be one of three things:
43 * - Two empty squares, if the browser doesn't render emoji
44 * - Two squares with 'U' and 'N' in them, if the browser doesn't render flag emoji
45 * - The United Nations flag
47 * The first two will encode to small images (1-2KB data URLs), the third will encode
48 * to a larger image (4-5KB data URL).
50 context.fillText( stringFromCharCode( 55356, 56826, 55356, 56819 ), 0, 0 );
51 if ( canvas.toDataURL().length < 3000 ) {
55 context.clearRect( 0, 0, canvas.width, canvas.height );
58 * Test for rainbow flag compatibility. As the rainbow flag was added out of sequence with
59 * the usual Unicode release cycle, some browsers support it, and some don't, even if their
60 * Unicode support is up to date.
62 * To test for support, we try to render it, and compare the rendering to how it would look if
63 * the browser doesn't render it correctly (white flag emoji + rainbow emoji).
65 context.fillText( stringFromCharCode( 55356, 57331, 65039, 8205, 55356, 57096 ), 0, 0 );
66 flag = canvas.toDataURL();
68 context.clearRect( 0, 0, canvas.width, canvas.height );
70 context.fillText( stringFromCharCode( 55356, 57331, 55356, 57096 ), 0, 0 );
71 flag2 = canvas.toDataURL();
73 return flag !== flag2;
76 * Emoji 4 has the best technologists. So does WordPress!
78 * To test for support, try to render a new emoji (woman technologist: medium skin tone),
79 * then compare it to how it would look if the browser doesn't render it correctly
80 * (woman technologist: medium skin tone + personal computer).
82 context.fillText( stringFromCharCode( 55357, 56425, 55356, 57341, 8205, 55357, 56507), 0, 0 );
83 technologist = canvas.toDataURL();
85 context.clearRect( 0, 0, canvas.width, canvas.height );
87 context.fillText( stringFromCharCode( 55357, 56425, 55356, 57341, 55357, 56507), 0, 0 );
88 technologist2 = canvas.toDataURL();
90 return technologist !== technologist2;
96 function addScript( src ) {
97 var script = document.createElement( 'script' );
100 script.defer = script.type = 'text/javascript';
101 document.getElementsByTagName( 'head' )[0].appendChild( script );
104 tests = Array( 'flag', 'emoji4' );
106 settings.supports = {
108 everythingExceptFlag: true
111 for( ii = 0; ii < tests.length; ii++ ) {
112 settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] );
114 settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ];
116 if ( 'flag' !== tests[ ii ] ) {
117 settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ];
121 settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag;
123 settings.DOMReady = false;
124 settings.readyCallback = function() {
125 settings.DOMReady = true;
128 if ( ! settings.supports.everything ) {
130 settings.readyCallback();
133 if ( document.addEventListener ) {
134 document.addEventListener( 'DOMContentLoaded', ready, false );
135 window.addEventListener( 'load', ready, false );
137 window.attachEvent( 'onload', ready );
138 document.attachEvent( 'onreadystatechange', function() {
139 if ( 'complete' === document.readyState ) {
140 settings.readyCallback();
145 src = settings.source || {};
147 if ( src.concatemoji ) {
148 addScript( src.concatemoji );
149 } else if ( src.wpemoji && src.twemoji ) {
150 addScript( src.twemoji );
151 addScript( src.wpemoji );
155 } )( window, document, window._wpemojiSettings );