wp-includes/js/wp-emoji-loader.js

   1 ( function( window, document, settings ) {
   2         var src, ready, ii, tests;
   3
   4         /**
   5          * Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
   6          * made of two characters, so some browsers (notably, Firefox OS X) don't support them.
   7          *
   8          * @since 4.2.0
   9          *
  10          * @param type {String} Whether to test for support of "simple", "flag", "diversity" or "unicode8" emoji.
  11          * @return {Boolean} True if the browser can render emoji, false if it cannot.
  12          */
  13         function browserSupportsEmoji( type ) {
  14                 var canvas = document.createElement( 'canvas' ),
  15                         context = canvas.getContext && canvas.getContext( '2d' ),
  16                         stringFromCharCode = String.fromCharCode,
  17                         flag, flag2, tonedata, tone, tone2;
  18
  19                 if ( ! context || ! context.fillText ) {
  20                         return false;
  21                 }
  22
  23                 /*
  24                  * Chrome on OS X added native emoji rendering in M41. Unfortunately,
  25                  * it doesn't work when the font is bolder than 500 weight. So, we
  26                  * check for bold rendering support to avoid invisible emoji in Chrome.
  27                  */
  28                 context.textBaseline = 'top';
  29                 context.font = '600 32px Arial';
  30
  31                 switch ( type ) {
  32                         case 'flag':
  33                                 /*
  34                                  * This works because the image will be one of three things:
  35                                  * - Two empty squares, if the browser doesn't render emoji
  36                                  * - Two squares with 'A' and 'U' in them, if the browser doesn't render flag emoji
  37                                  * - The Australian flag
  38                                  *
  39                                  * The first two will encode to small images (1-2KB data URLs), the third will encode
  40                                  * to a larger image (4-5KB data URL).
  41                                  */
  42                                 context.fillText( stringFromCharCode( 55356, 56806, 55356, 56826 ), 0, 0 );
  43                                 if ( canvas.toDataURL().length < 3000 ) {
  44                                         return false;
  45                                 }
  46
  47                                 context.clearRect( 0, 0, canvas.width, canvas.height );
  48
  49                                 /*
  50                                  * Test for rainbow flag compatibility. As the rainbow flag was added out of sequence with
  51                                  * the usual Unicode release cycle, some browsers support it, and some don't, even if their
  52                                  * Unicode support is up to date.
  53                                  *
  54                                  * To test for support, we try to render it, and compare the rendering to how it would look if
  55                                  * the browser doesn't render it correctly (white flag emoji + rainbow emoji).
  56                                  */
  57                                 context.fillText( stringFromCharCode( 55356, 57331, 65039, 8205, 55356, 57096 ), 0, 0 );
  58                                 flag = canvas.toDataURL();
  59
  60                                 context.clearRect( 0, 0, canvas.width, canvas.height );
  61
  62                                 context.fillText( stringFromCharCode( 55356, 57331, 55356, 57096 ), 0, 0 );
  63                                 flag2 = canvas.toDataURL();
  64
  65                                 return flag !== flag2;
  66                         case 'diversity':
  67                                 /*
  68                                  * This tests if the browser supports the Emoji Diversity specification, by rendering an
  69                                  * emoji with no skin tone specified (in this case, Santa). It then adds a skin tone, and
  70                                  * compares if the emoji rendering has changed.
  71                                  */
  72                                 context.fillText( stringFromCharCode( 55356, 57221 ), 0, 0 );
  73                                 tonedata = context.getImageData( 16, 16, 1, 1 ).data;
  74                                 tone = tonedata[0] + ',' + tonedata[1] + ',' + tonedata[2] + ',' + tonedata[3];
  75
  76                                 context.fillText( stringFromCharCode( 55356, 57221, 55356, 57343 ), 0, 0 );
  77                                 // Chrome has issues comparing arrays, and Safari has issues converting arrays to strings.
  78                                 // So, we create our own string and compare that, instead.
  79                                 tonedata = context.getImageData( 16, 16, 1, 1 ).data;
  80                                 tone2 = tonedata[0] + ',' + tonedata[1] + ',' + tonedata[2] + ',' + tonedata[3];
  81
  82                                 return tone !== tone2;
  83                         case 'simple':
  84                                 /*
  85                                  * This creates a smiling emoji, and checks to see if there is any image data in the
  86                                  * center pixel. In browsers that don't support emoji, the character will be rendered
  87                                  * as an empty square, so the center pixel will be blank.
  88                                  */
  89                                 context.fillText( stringFromCharCode( 55357, 56835 ), 0, 0 );
  90                                 return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
  91                         case 'unicode8':
  92                                 /*
  93                                  * To check for Unicode 8 support, let's try rendering the most important advancement
  94                                  * that the Unicode Consortium have made in years: the burrito.
  95                                  */
  96                                 context.fillText( stringFromCharCode( 55356, 57135 ), 0, 0 );
  97                                 return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
  98                         case 'unicode9':
  99                                 /*
 100                                  * Do Unicode 9 emoji render?
 101                                  * ¯\_(ツ)_/¯
 102                                  */
 103                                 context.fillText( stringFromCharCode( 55358, 56631 ), 0, 0 );
 104                                 return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
 105                 }
 106
 107                 return false;
 108         }
 109
 110         function addScript( src ) {
 111                 var script = document.createElement( 'script' );
 112
 113                 script.src = src;
 114                 script.type = 'text/javascript';
 115                 document.getElementsByTagName( 'head' )[0].appendChild( script );
 116         }
 117
 118         tests = Array( 'simple', 'flag', 'unicode8', 'diversity', 'unicode9' );
 119
 120         settings.supports = {
 121                 everything: true,
 122                 everythingExceptFlag: true
 123         };
 124
 125         for( ii = 0; ii < tests.length; ii++ ) {
 126                 settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] );
 127
 128                 settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ];
 129
 130                 if ( 'flag' !== tests[ ii ] ) {
 131                         settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ];
 132                 }
 133         }
 134
 135         settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag;
 136
 137         settings.DOMReady = false;
 138         settings.readyCallback = function() {
 139                 settings.DOMReady = true;
 140         };
 141
 142         if ( ! settings.supports.everything ) {
 143                 ready = function() {
 144                         settings.readyCallback();
 145                 };
 146
 147                 if ( document.addEventListener ) {
 148                         document.addEventListener( 'DOMContentLoaded', ready, false );
 149                         window.addEventListener( 'load', ready, false );
 150                 } else {
 151                         window.attachEvent( 'onload', ready );
 152                         document.attachEvent( 'onreadystatechange', function() {
 153                                 if ( 'complete' === document.readyState ) {
 154                                         settings.readyCallback();
 155                                 }
 156                         } );
 157                 }
 158
 159                 src = settings.source || {};
 160
 161                 if ( src.concatemoji ) {
 162                         addScript( src.concatemoji );
 163                 } else if ( src.wpemoji && src.twemoji ) {
 164                         addScript( src.twemoji );
 165                         addScript( src.wpemoji );
 166                 }
 167         }
 168
 169 } )( window, document, window._wpemojiSettings );