126 lines
4.3 KiB
JavaScript
126 lines
4.3 KiB
JavaScript
( function( window, document, settings ) {
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var src, ready;
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/**
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* Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
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* made of two characters, so some browsers (notably, Firefox OS X) don't support them.
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*
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* @since 4.2.0
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*
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* @param type {String} Whether to test for support of "simple" or "flag" emoji.
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* @return {Boolean} True if the browser can render emoji, false if it cannot.
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*/
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function browserSupportsEmoji( type ) {
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var canvas = document.createElement( 'canvas' ),
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context = canvas.getContext && canvas.getContext( '2d' ),
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stringFromCharCode = String.fromCharCode,
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tonedata, tone, tone2;
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if ( ! context || ! context.fillText ) {
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return false;
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}
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/*
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* Chrome on OS X added native emoji rendering in M41. Unfortunately,
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* it doesn't work when the font is bolder than 500 weight. So, we
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* check for bold rendering support to avoid invisible emoji in Chrome.
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*/
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context.textBaseline = 'top';
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context.font = '600 32px Arial';
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if ( 'flag' === type ) {
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/*
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* This works because the image will be one of three things:
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* - Two empty squares, if the browser doesn't render emoji
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* - Two squares with 'A' and 'U' in them, if the browser doesn't render flag emoji
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* - The Australian flag
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*
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* The first two will encode to small images (1-2KB data URLs), the third will encode
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* to a larger image (4-5KB data URL).
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*/
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context.fillText( stringFromCharCode( 55356, 56806, 55356, 56826 ), 0, 0 );
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return canvas.toDataURL().length > 3000;
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} else if ( 'diversity' === type ) {
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/*
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* This tests if the browser supports the Emoji Diversity specification, by rendering an
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* emoji with no skin tone specified (in this case, Santa). It then adds a skin tone, and
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* compares if the emoji rendering has changed.
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*/
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context.fillText( stringFromCharCode( 55356, 57221 ), 0, 0 );
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tonedata = context.getImageData( 16, 16, 1, 1 ).data;
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context.fillText( stringFromCharCode( 55356, 57221, 55356, 57343 ), 0, 0 );
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// Chrome has issues comparing arrays, and Safari has issues converting arrays to strings.
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// So, we create our own string and compare that, instead.
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tonedata = context.getImageData( 16, 16, 1, 1 ).data;
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tone2 = tonedata[0] + ',' + tonedata[1] + ',' + tonedata[2] + ',' + tonedata[3];
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return tone !== tone2;
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} else {
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if ( 'simple' === type ) {
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/*
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* This creates a smiling emoji, and checks to see if there is any image data in the
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* center pixel. In browsers that don't support emoji, the character will be rendered
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* as an empty square, so the center pixel will be blank.
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*/
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context.fillText( stringFromCharCode( 55357, 56835 ), 0, 0 );
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} else {
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/*
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* To check for Unicode 8 support, let's try rendering the most important advancement
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* that the Unicode Consortium have made in years: the burrito.
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*/
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context.fillText( stringFromCharCode( 55356, 57135 ), 0, 0 );
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}
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return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
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}
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}
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function addScript( src ) {
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var script = document.createElement( 'script' );
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script.src = src;
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script.type = 'text/javascript';
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document.getElementsByTagName( 'head' )[0].appendChild( script );
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}
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settings.supports = {
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simple: browserSupportsEmoji( 'simple' ),
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flag: browserSupportsEmoji( 'flag' ),
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unicode8: browserSupportsEmoji( 'unicode8' ),
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diversity: browserSupportsEmoji( 'diversity' )
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};
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settings.DOMReady = false;
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settings.readyCallback = function() {
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settings.DOMReady = true;
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};
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if ( ! settings.supports.simple || ! settings.supports.flag || ! settings.supports.unicode8 || ! settings.supports.diversity ) {
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ready = function() {
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settings.readyCallback();
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};
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if ( document.addEventListener ) {
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document.addEventListener( 'DOMContentLoaded', ready, false );
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window.addEventListener( 'load', ready, false );
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} else {
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window.attachEvent( 'onload', ready );
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document.attachEvent( 'onreadystatechange', function() {
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if ( 'complete' === document.readyState ) {
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settings.readyCallback();
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}
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} );
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}
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src = settings.source || {};
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if ( src.concatemoji ) {
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addScript( src.concatemoji );
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} else if ( src.wpemoji && src.twemoji ) {
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addScript( src.twemoji );
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addScript( src.wpemoji );
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}
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}
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} )( window, document, window._wpemojiSettings );
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