Changeset 38194 for trunk/src/wp-includes/js/wp-emoji-loader.js

Timestamp:

08/04/2016 08:50:11 PM (8 years ago)

Author:

ocean90

Message:

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.

File:

• trunk/src/wp-includes/js/wp-emoji-loader.js (modified) (2 diffs)

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

@@ -15 +15 @@
             context = canvas.getContext && canvas.getContext( '2d' ),
             stringFromCharCode = String.fromCharCode,
-            tonedata, tone, tone2;
+            flag, flag2, tonedata, tone, tone2;
 
         if ( ! context || ! context.fillText ) {
@@ -41 +41 @@
                  */
                 context.fillText( stringFromCharCode( 55356, 56806, 55356, 56826 ), 0, 0 );
-                return canvas.toDataURL().length > 3000;
+                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':
                 /*