fix(ttml): Default TTML background color to transparent if unspecified (

#4496) Closes #4468
shaka-project · Sep 28, 2022 · 32b0a90 · 32b0a90
1 parent b3621c2
commit 32b0a90
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Showing 3 changed files with 52 additions and 2 deletions.
diff --git a/lib/text/ttml_text_parser.js b/lib/text/ttml_text_parser.js
@@ -164,6 +164,12 @@ shaka.text.TtmlTextParser = class {
           cellResolutionInfo, /* parentCueElement= */ null,
           /* isContent= */ false);
       if (cue) {
+        // According to the TTML spec, backgrounds default to transparent.
+        // So default the background of the top-level element to transparent.
+        // Nested elements may override that background color already.
+        if (!cue.backgroundColor) {
+          cue.backgroundColor = 'transparent';
+        }
         cues.push(cue);
       }
     }

diff --git a/test/test/util/ttml_utils.js b/test/test/util/ttml_utils.js
@@ -51,8 +51,6 @@ shaka.test.TtmlUtils = class {
         region,
         nestedCues: jasmine.any(Object),
         payload: '',
-        startTime: 0,
-        endTime: Infinity,
         isContainer: true,
       });
       Object.assign(containerCue, properties);

diff --git a/test/text/ttml_text_parser_unit.js b/test/text/ttml_text_parser_unit.js
@@ -1535,6 +1535,52 @@ describe('TtmlTextParser', () => {
         {startTime: 1, endTime: 2});
   });
 
+  // Regression test for #4468
+  it('defaults the body background to transparent', () => {
+    verifyHelper(
+        // One cue, don't care about the details
+        [{}],
+        '<tt xmlns:tts="http://www.w3.org/ns/ttml#styling">' +
+        '<head>' +
+        '<styling>' +
+        '<style xml:id="s1" tts:backgroundColor="black" />' +
+        '</styling>' +
+        '</head>' +
+        '<body><div>' +
+        '<p begin="00:01.00" end="00:02.00">' +
+        '<span style="s1">Test</span>' +
+        '</p>' +
+        '</div></body></tt>',
+        {periodStart: 0, segmentStart: 0, segmentEnd: 0, vttOffset: 0},
+        // The body must have these properties:
+        {backgroundColor: 'transparent'},
+        // The div must have these properties:
+        {});  // don't care
+  });
+
+  // Regression test for #4468
+  it('allows the body background color to be set', () => {
+    verifyHelper(
+        // One cue, don't care about the details
+        [{}],
+        '<tt xmlns:tts="http://www.w3.org/ns/ttml#styling">' +
+        '<head>' +
+        '<styling>' +
+        '<style xml:id="s1" tts:backgroundColor="black" />' +
+        '</styling>' +
+        '</head>' +
+        '<body style="s1"><div>' +
+        '<p begin="00:01.00" end="00:02.00">' +
+        '<span>Test</span>' +
+        '</p>' +
+        '</div></body></tt>',
+        {periodStart: 0, segmentStart: 0, segmentEnd: 0, vttOffset: 0},
+        // The body must have these properties:
+        {backgroundColor: 'black'},
+        // The div must have these properties:
+        {});  // don't care
+  });
+
   it('parses wrapping option', () => {
     verifyHelper(
         [