WordPress/wp-includes/js/wp-emoji-loader.js
Dominik Schilling ea6e749c71 Emoji: Update the Twemoji loader to include the rainbow flag.
[38179] added support for the rainbow flag to core, but platform compatibility is a bit strange, because the flag was defined out of sync with the usual Unicode release cycle. For example Android N supports all Unicode 9.0 emoji, but doesn't support the rainbow flag thus the rainbow flag isn't rendered.
The Twemoji loader already has an exception for flags - it'll load if the browser supports everything but flags, and then only replace flag emoji, leaving everything else as native rendering. To provide a seamless experience for all flags the loader now uses the rainbow flag to test flag support.

Props pento.
See #37543.
Fixes #37566.
Built from https://develop.svn.wordpress.org/trunk@38194


git-svn-id: http://core.svn.wordpress.org/trunk@38135 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2016-08-04 20:51:31 +00:00

170 lines
5.9 KiB
JavaScript

( function( window, document, settings ) {
var src, ready, ii, tests;
/**
* 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 "simple", "flag", "diversity" or "unicode8" emoji.
* @return {Boolean} True if the browser can render emoji, false if it cannot.
*/
function browserSupportsEmoji( type ) {
var canvas = document.createElement( 'canvas' ),
context = canvas.getContext && canvas.getContext( '2d' ),
stringFromCharCode = String.fromCharCode,
flag, flag2, tonedata, tone, tone2;
if ( ! context || ! context.fillText ) {
return false;
}
/*
* 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 'A' and 'U' in them, if the browser doesn't render flag emoji
* - The Australian 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, 56806, 55356, 56826 ), 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 'diversity':
/*
* This tests if the browser supports the Emoji Diversity specification, by rendering an
* emoji with no skin tone specified (in this case, Santa). It then adds a skin tone, and
* compares if the emoji rendering has changed.
*/
context.fillText( stringFromCharCode( 55356, 57221 ), 0, 0 );
tonedata = context.getImageData( 16, 16, 1, 1 ).data;
tone = tonedata[0] + ',' + tonedata[1] + ',' + tonedata[2] + ',' + tonedata[3];
context.fillText( stringFromCharCode( 55356, 57221, 55356, 57343 ), 0, 0 );
// Chrome has issues comparing arrays, and Safari has issues converting arrays to strings.
// So, we create our own string and compare that, instead.
tonedata = context.getImageData( 16, 16, 1, 1 ).data;
tone2 = tonedata[0] + ',' + tonedata[1] + ',' + tonedata[2] + ',' + tonedata[3];
return tone !== tone2;
case 'simple':
/*
* This creates a smiling emoji, and checks to see if there is any image data in the
* center pixel. In browsers that don't support emoji, the character will be rendered
* as an empty square, so the center pixel will be blank.
*/
context.fillText( stringFromCharCode( 55357, 56835 ), 0, 0 );
return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
case 'unicode8':
/*
* To check for Unicode 8 support, let's try rendering the most important advancement
* that the Unicode Consortium have made in years: the burrito.
*/
context.fillText( stringFromCharCode( 55356, 57135 ), 0, 0 );
return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
case 'unicode9':
/*
* Do Unicode 9 emoji render?
* ¯\_(ツ)_/¯
*/
context.fillText( stringFromCharCode( 55358, 56631 ), 0, 0 );
return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
}
return false;
}
function addScript( src ) {
var script = document.createElement( 'script' );
script.src = src;
script.type = 'text/javascript';
document.getElementsByTagName( 'head' )[0].appendChild( script );
}
tests = Array( 'simple', 'flag', 'unicode8', 'diversity', 'unicode9' );
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 );