( function( window, document, settings ) {
var src, ready, ii, tests;
/*
* Create a canvas element for testing native browser support
* of emoji.
*/
var canvas = document.createElement( 'canvas' );
var context = canvas.getContext && canvas.getContext( '2d' );
/**
* Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
* made of two characters, so some browsers (notably, Firefox OS X) don't support them.
*
* @since 4.2.0
*
* @param type {String} Whether to test for support of "flag" or "emoji4" emoji.
* @return {Boolean} True if the browser can render emoji, false if it cannot.
*/
function browserSupportsEmoji( type ) {
var stringFromCharCode = String.fromCharCode,
flag, flag2, technologist, technologist2;
if ( ! context || ! context.fillText ) {
return false;
}
// Cleanup from previous test.
context.clearRect( 0, 0, canvas.width, canvas.height );
/*
* Chrome on OS X added native emoji rendering in M41. Unfortunately,
* it doesn't work when the font is bolder than 500 weight. So, we
* check for bold rendering support to avoid invisible emoji in Chrome.
*/
context.textBaseline = 'top';
context.font = '600 32px Arial';
switch ( type ) {
case 'flag':
/*
* This works because the image will be one of three things:
* - Two empty squares, if the browser doesn't render emoji
* - Two squares with 'U' and 'N' in them, if the browser doesn't render flag emoji
* - The United Nations flag
*
* The first two will encode to small images (1-2KB data URLs), the third will encode
* to a larger image (4-5KB data URL).
*/
context.fillText( stringFromCharCode( 55356, 56826, 55356, 56819 ), 0, 0 );
if ( canvas.toDataURL().length < 3000 ) {
return false;
}
context.clearRect( 0, 0, canvas.width, canvas.height );
/*
* Test for rainbow flag compatibility. As the rainbow flag was added out of sequence with
* the usual Unicode release cycle, some browsers support it, and some don't, even if their
* Unicode support is up to date.
*
* To test for support, we try to render it, and compare the rendering to how it would look if
* the browser doesn't render it correctly (white flag emoji + rainbow emoji).
*/
context.fillText( stringFromCharCode( 55356, 57331, 65039, 8205, 55356, 57096 ), 0, 0 );
flag = canvas.toDataURL();
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode( 55356, 57331, 55356, 57096 ), 0, 0 );
flag2 = canvas.toDataURL();
return flag !== flag2;
case 'emoji4':
/*
* Emoji 4 has the best technologists. So does WordPress!
*
* To test for support, try to render a new emoji (woman technologist: medium skin tone),
* then compare it to how it would look if the browser doesn't render it correctly
* (woman technologist: medium skin tone + personal computer).
*/
context.fillText( stringFromCharCode( 55357, 56425, 55356, 57341, 8205, 55357, 56507), 0, 0 );
technologist = canvas.toDataURL();
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode( 55357, 56425, 55356, 57341, 55357, 56507), 0, 0 );
technologist2 = canvas.toDataURL();
return technologist !== technologist2;
}
return false;
}
function addScript( src ) {
var script = document.createElement( 'script' );
script.src = src;
script.defer = script.type = 'text/javascript';
document.getElementsByTagName( 'head' )[0].appendChild( script );
}
tests = Array( 'flag', 'emoji4' );
settings.supports = {
everything: true,
everythingExceptFlag: true
};
for( ii = 0; ii < tests.length; ii++ ) {
settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] );
settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ];
if ( 'flag' !== tests[ ii ] ) {
settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ];
}
}
settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag;
settings.DOMReady = false;
settings.readyCallback = function() {
settings.DOMReady = true;
};
if ( ! settings.supports.everything ) {
ready = function() {
settings.readyCallback();
};
if ( document.addEventListener ) {
document.addEventListener( 'DOMContentLoaded', ready, false );
window.addEventListener( 'load', ready, false );
} else {
window.attachEvent( 'onload', ready );
document.attachEvent( 'onreadystatechange', function() {
if ( 'complete' === document.readyState ) {
settings.readyCallback();
}
} );
}
src = settings.source || {};
if ( src.concatemoji ) {
addScript( src.concatemoji );
} else if ( src.wpemoji && src.twemoji ) {
addScript( src.twemoji );
addScript( src.wpemoji );
}
}
} )( window, document, window._wpemojiSettings );
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