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Emoji: Refactor browser support tests.

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Moves the repeated code in the emoji browser support test to a function to reduced the potential for errors and follow DRY principles.

Renames the "emoji4" test "emoji" as unicode version specific tests were removed in [38869].

Props peterwilsoncc, pento for code review.
Fixes #41156.



git-svn-id: https://develop.svn.wordpress.org/trunk@41669 602fd350-edb4-49c9-b593-d223f7449a82
This commit is contained in:
Peter Wilson 2017-10-02 03:59:50 +00:00
parent 28b28b581a
commit 1059c44025
1 changed files with 42 additions and 37 deletions
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79
src/wp-includes/js/wp-emoji-loader.js
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@ -8,26 +8,45 @@
var canvas = document.createElement( 'canvas' );
var context = canvas.getContext && canvas.getContext( '2d' );
/**
* Check if two sets of Emoji characters render the same.
*
* @param set1 array Set of Emoji characters.
* @param set2 array Set of Emoji characters.
* @returns {boolean} True if the two sets render the same.
*/
function emojiSetsRenderIdentically( set1, set2 ) {
var stringFromCharCode = String.fromCharCode;
// Cleanup from previous test.
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode.apply( this, set1 ), 0, 0 );
var rendered1 = canvas.toDataURL();
// Cleanup from previous test.
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode.apply( this, set2 ), 0, 0 );
var rendered2 = canvas.toDataURL();
return rendered1 === rendered2;
}
/**
* 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.
* @param type {String} Whether to test for support of "flag" or "emoji".
* @return {Boolean} True if the browser can render emoji, false if it cannot.
*/
function browserSupportsEmoji( type ) {
var stringFromCharCode = String.fromCharCode,
flag, flag2, emoji41, emoji42;
var isIdentical;
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
@ -45,16 +64,12 @@
* 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 ([U] + [N]).
*/
context.fillText( stringFromCharCode( 55356, 56826, 55356, 56819 ), 0, 0 );
flag = canvas.toDataURL();
isIdentical = emojiSetsRenderIdentically(
[ 55356, 56826, 55356, 56819 ],
[ 55356, 56826, 8203, 55356, 56819 ]
);
context.clearRect( 0, 0, canvas.width, canvas.height );
// Add a zero width space between the characters, to force rendering as characters.
context.fillText( stringFromCharCode( 55356, 56826, 8203, 55356, 56819 ), 0, 0 );
flag2 = canvas.toDataURL();
if ( flag === flag2 ) {
if ( isIdentical ) {
return false;
}
@ -65,19 +80,13 @@
* 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 (black flag emoji + [G] + [B] + [E] + [N] + [G]).
*/
// Cleanup from previous test.
context.clearRect( 0, 0, canvas.width, canvas.height );
isIdentical = emojiSetsRenderIdentically(
[ 55356, 57332, 56128, 56423, 56128, 56418, 56128, 56421, 56128, 56430, 56128, 56423, 56128, 56447 ],
[ 55356, 57332, 8203, 56128, 56423, 8203, 56128, 56418, 8203, 56128, 56421, 8203, 56128, 56430, 8203, 56128, 56423, 8203, 56128, 56447 ]
);
context.fillText( stringFromCharCode( 55356, 57332, 56128, 56423, 56128, 56418, 56128, 56421, 56128, 56430, 56128, 56423, 56128, 56447 ), 0, 0 );
flag = canvas.toDataURL();
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode( 55356, 57332, 8203, 56128, 56423, 8203, 56128, 56418, 8203, 56128, 56421, 8203, 56128, 56430, 8203, 56128, 56423, 8203, 56128, 56447 ), 0, 0 );
flag2 = canvas.toDataURL();
return flag !== flag2;
case 'emoji4':
return ! isIdentical;
case 'emoji':
/*
* Emoji 5 has fairies of all genders.
*
@ -85,15 +94,11 @@
* it to how it would look if the browser doesn't render it correctly
* (fairy + male sign).
*/
context.fillText( stringFromCharCode( 55358, 56794, 8205, 9794, 65039 ), 0, 0 );
emoji41 = canvas.toDataURL();
context.clearRect( 0, 0, canvas.width, canvas.height );
context.fillText( stringFromCharCode( 55358, 56794, 8203, 9794, 65039 ), 0, 0 );
emoji42 = canvas.toDataURL();
return emoji41 !== emoji42;
isIdentical = emojiSetsRenderIdentically(
[ 55358, 56794, 8205, 9794, 65039 ],
[ 55358, 56794, 8203, 9794, 65039 ]
);
return ! isIdentical;
}
return false;
@ -107,7 +112,7 @@
document.getElementsByTagName( 'head' )[0].appendChild( script );
}
tests = Array( 'flag', 'emoji4' );
tests = Array( 'flag', 'emoji' );
settings.supports = {
everything: true,