Ticket #41156: 41156.diff

src/wp-includes/js/wp-emoji-loader.js

@@ -8 +8 @@
         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 +64 @@
                                  * 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 +80 @@
                                  * 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 );
-
-                                context.fillText( stringFromCharCode( 55356, 57332, 56128, 56423, 56128, 56418, 56128, 56421, 56128, 56430, 56128, 56423, 56128, 56447 ), 0, 0 );
-                                flag = canvas.toDataURL();
+                                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.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 +94 @@
                                  * 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 +112 @@
                 document.getElementsByTagName( 'head' )[0].appendChild( script );
         }
 
-        tests = Array( 'flag', 'emoji4' );
+        tests = Array( 'flag', 'emoji' );
 
         settings.supports = {
                 everything: true,