wp/wp-includes/js/wp-emoji-loader.js
changeset 7 cf61fcea0001
parent 5 5e2f62d02dcd
child 9 177826044cd9
equal deleted inserted replaced
6:490d5cc509ed 7:cf61fcea0001
     1 ( function( window, document, settings ) {
     1 ( function( window, document, settings ) {
     2 	var src, ready;
     2 	var src, ready, ii, tests;
       
     3 
       
     4 	/*
       
     5 	 * Create a canvas element for testing native browser support
       
     6 	 * of emoji.
       
     7 	 */
       
     8 	var canvas = document.createElement( 'canvas' );
       
     9 	var context = canvas.getContext && canvas.getContext( '2d' );
       
    10 
       
    11 	/**
       
    12 	 * Check if two sets of Emoji characters render the same.
       
    13 	 *
       
    14 	 * @param set1 array Set of Emoji characters.
       
    15 	 * @param set2 array Set of Emoji characters.
       
    16 	 * @returns {boolean} True if the two sets render the same.
       
    17 	 */
       
    18 	function emojiSetsRenderIdentically( set1, set2 ) {
       
    19 		var stringFromCharCode = String.fromCharCode;
       
    20 
       
    21 		// Cleanup from previous test.
       
    22 		context.clearRect( 0, 0, canvas.width, canvas.height );
       
    23 		context.fillText( stringFromCharCode.apply( this, set1 ), 0, 0 );
       
    24 		var rendered1 = canvas.toDataURL();
       
    25 
       
    26 		// Cleanup from previous test.
       
    27 		context.clearRect( 0, 0, canvas.width, canvas.height );
       
    28 		context.fillText( stringFromCharCode.apply( this, set2 ), 0, 0 );
       
    29 		var rendered2 = canvas.toDataURL();
       
    30 
       
    31 		return rendered1 === rendered2;
       
    32 	}
     3 
    33 
     4 	/**
    34 	/**
     5 	 * Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
    35 	 * 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.
    36 	 * made of two characters, so some browsers (notably, Firefox OS X) don't support them.
     7 	 *
    37 	 *
     8 	 * @since 4.2.0
    38 	 * @since 4.2.0
     9 	 *
    39 	 *
    10 	 * @param type {String} Whether to test for support of "simple" or "flag" emoji.
    40 	 * @param type {String} Whether to test for support of "flag" or "emoji".
    11 	 * @return {Boolean} True if the browser can render emoji, false if it cannot.
    41 	 * @return {Boolean} True if the browser can render emoji, false if it cannot.
    12 	 */
    42 	 */
    13 	function browserSupportsEmoji( type ) {
    43 	function browserSupportsEmoji( type ) {
    14 		var canvas = document.createElement( 'canvas' ),
    44 		var isIdentical;
    15 			context = canvas.getContext && canvas.getContext( '2d' );
       
    16 
    45 
    17 		if ( ! context || ! context.fillText ) {
    46 		if ( ! context || ! context.fillText ) {
    18 			return false;
    47 			return false;
    19 		}
    48 		}
    20 
    49 
    24 		 * check for bold rendering support to avoid invisible emoji in Chrome.
    53 		 * check for bold rendering support to avoid invisible emoji in Chrome.
    25 		 */
    54 		 */
    26 		context.textBaseline = 'top';
    55 		context.textBaseline = 'top';
    27 		context.font = '600 32px Arial';
    56 		context.font = '600 32px Arial';
    28 
    57 
    29 		if ( type === 'flag' ) {
    58 		switch ( type ) {
    30 			/*
    59 			case 'flag':
    31 			 * This works because the image will be one of three things:
    60 				/*
    32 			 * - Two empty squares, if the browser doesn't render emoji
    61 				 * Test for UN flag compatibility. This is the least supported of the letter locale flags,
    33 			 * - Two squares with 'G' and 'B' in them, if the browser doesn't render flag emoji
    62 				 * so gives us an easy test for full support.
    34 			 * - The British flag
    63 				 *
    35 			 *
    64 				 * To test for support, we try to render it, and compare the rendering to how it would look if
    36 			 * The first two will encode to small images (1-2KB data URLs), the third will encode
    65 				 * the browser doesn't render it correctly ([U] + [N]).
    37 			 * to a larger image (4-5KB data URL).
    66 				 */
    38 			 */
    67 				isIdentical = emojiSetsRenderIdentically(
    39 			context.fillText( String.fromCharCode( 55356, 56812, 55356, 56807 ), 0, 0 );
    68 					[ 55356, 56826, 55356, 56819 ],
    40 			return canvas.toDataURL().length > 3000;
    69 					[ 55356, 56826, 8203, 55356, 56819 ]
    41 		} else {
    70 				);
    42 			/*
    71 
    43 			 * This creates a smiling emoji, and checks to see if there is any image data in the
    72 				if ( isIdentical ) {
    44 			 * center pixel. In browsers that don't support emoji, the character will be rendered
    73 					return false;
    45 			 * as an empty square, so the center pixel will be blank.
    74 				}
    46 			 */
    75 
    47 			context.fillText( String.fromCharCode( 55357, 56835 ), 0, 0 );
    76 				/*
    48 			return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
    77 				 * Test for English flag compatibility. England is a country in the United Kingdom, it
       
    78 				 * does not have a two letter locale code but rather an five letter sub-division code.
       
    79 				 *
       
    80 				 * To test for support, we try to render it, and compare the rendering to how it would look if
       
    81 				 * the browser doesn't render it correctly (black flag emoji + [G] + [B] + [E] + [N] + [G]).
       
    82 				 */
       
    83 				isIdentical = emojiSetsRenderIdentically(
       
    84 					[ 55356, 57332, 56128, 56423, 56128, 56418, 56128, 56421, 56128, 56430, 56128, 56423, 56128, 56447 ],
       
    85 					[ 55356, 57332, 8203, 56128, 56423, 8203, 56128, 56418, 8203, 56128, 56421, 8203, 56128, 56430, 8203, 56128, 56423, 8203, 56128, 56447 ]
       
    86 				);
       
    87 
       
    88 				return ! isIdentical;
       
    89 			case 'emoji':
       
    90 				/*
       
    91 				 * She's the hero Emoji deserves, but not the one it needs right now.
       
    92 				 *
       
    93 				 * To test for support, try to render a new emoji (female superhero),
       
    94 				 * then compare it to how it would look if the browser doesn't render it correctly
       
    95 				 * (superhero + female sign).
       
    96 				 */
       
    97 				isIdentical = emojiSetsRenderIdentically(
       
    98 					[55358, 56760, 9792, 65039],
       
    99 					[55358, 56760, 8203, 9792, 65039]
       
   100 				);
       
   101 				return ! isIdentical;
    49 		}
   102 		}
       
   103 
       
   104 		return false;
    50 	}
   105 	}
    51 
   106 
    52 	function addScript( src ) {
   107 	function addScript( src ) {
    53 		var script = document.createElement( 'script' );
   108 		var script = document.createElement( 'script' );
    54 
   109 
    55 		script.src = src;
   110 		script.src = src;
    56 		script.type = 'text/javascript';
   111 		script.defer = script.type = 'text/javascript';
    57 		document.getElementsByTagName( 'head' )[0].appendChild( script );
   112 		document.getElementsByTagName( 'head' )[0].appendChild( script );
    58 	}
   113 	}
    59 
   114 
       
   115 	tests = Array( 'flag', 'emoji' );
       
   116 
    60 	settings.supports = {
   117 	settings.supports = {
    61 		simple: browserSupportsEmoji( 'simple' ),
   118 		everything: true,
    62 		flag:   browserSupportsEmoji( 'flag' )
   119 		everythingExceptFlag: true
    63 	};
   120 	};
       
   121 
       
   122 	for( ii = 0; ii < tests.length; ii++ ) {
       
   123 		settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] );
       
   124 
       
   125 		settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ];
       
   126 
       
   127 		if ( 'flag' !== tests[ ii ] ) {
       
   128 			settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ];
       
   129 		}
       
   130 	}
       
   131 
       
   132 	settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag;
    64 
   133 
    65 	settings.DOMReady = false;
   134 	settings.DOMReady = false;
    66 	settings.readyCallback = function() {
   135 	settings.readyCallback = function() {
    67 		settings.DOMReady = true;
   136 		settings.DOMReady = true;
    68 	};
   137 	};
    69 
   138 
    70 	if ( ! settings.supports.simple || ! settings.supports.flag ) {
   139 	if ( ! settings.supports.everything ) {
    71 		ready = function() {
   140 		ready = function() {
    72 			settings.readyCallback();
   141 			settings.readyCallback();
    73 		};
   142 		};
    74 
   143 
    75 		if ( document.addEventListener ) {
   144 		if ( document.addEventListener ) {