Changeset 225310 in webkit

Timestamp:

Nov 29, 2017 5:50:14 PM (6 years ago)

Author:

Simon Fraser

Message:

Missing layer content when animating elements on-screen
​https://bugs.webkit.org/show_bug.cgi?id=180178
rdar://problem/34923438

Reviewed by Dean Jackson.

If a delayed animation starts, that animates layers from offscreen, then we would fail
to run the logic that ensures that those layers have backing store.

Fix by ensuring that if any layer starts or ends a transform animation, we re-evaluate
backing store attachment on all its descendants.

I tried to make a test, but layer flushing is timing-sensitive and the test would have taken
5s, and not been reliable. There's a manual test in the bug.

• platform/graphics/ca/GraphicsLayerCA.cpp:

(WebCore::GraphicsLayerCA::recursiveCommitChanges):

• platform/graphics/ca/GraphicsLayerCA.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/ca/GraphicsLayerCA.cpp (modified) (2 diffs)
• platform/graphics/ca/GraphicsLayerCA.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2017-11-29  Simon Fraser  <simon.fraser@apple.com>
+
+        Missing layer content when animating elements on-screen
+        https://bugs.webkit.org/show_bug.cgi?id=180178
+        rdar://problem/34923438
+
+        Reviewed by Dean Jackson.
+
+        If a delayed animation starts, that animates layers from offscreen, then we would fail
+        to run the logic that ensures that those layers have backing store.
+
+        Fix by ensuring that if any layer starts or ends a transform animation, we re-evaluate
+        backing store attachment on all its descendants.
+
+        I tried to make a test, but layer flushing is timing-sensitive and the test would have taken
+        5s, and not been reliable. There's a manual test in the bug.
+
+        * platform/graphics/ca/GraphicsLayerCA.cpp:
+        (WebCore::GraphicsLayerCA::recursiveCommitChanges):
+        * platform/graphics/ca/GraphicsLayerCA.h:
+
 2017-11-29  Youenn Fablet  <youenn@apple.com>
 

trunk/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp

@@ -1463 +1463 @@
     setVisibleAndCoverageRects(rects, m_isViewportConstrained || commitState.ancestorIsViewportConstrained);
 
+    if (commitState.ancestorStartedOrEndedTransformAnimation)
+        addUncommittedChanges(CoverageRectChanged);
+
 #ifdef VISIBLE_TILE_WASH
     // Use having a transform as a key to making the tile wash layer. If every layer gets a wash,
@@ -1502 +1505 @@
         baseRelativePosition += m_position;
 
+    bool wasRunningTransformAnimation = isRunningTransformAnimation();
+
     commitLayerChangesBeforeSublayers(childCommitState, pageScaleFactor, baseRelativePosition);
 
-    if (isRunningTransformAnimation()) {
+    bool nowRunningTransformAnimation = wasRunningTransformAnimation;
+    if (m_uncommittedChanges & AnimationChanged)
+        nowRunningTransformAnimation = isRunningTransformAnimation();
+
+    if (wasRunningTransformAnimation != nowRunningTransformAnimation)
+        childCommitState.ancestorStartedOrEndedTransformAnimation = true;
+
+    if (nowRunningTransformAnimation) {
         childCommitState.ancestorHasTransformAnimation = true;
         if (m_intersectsCoverageRect)

trunk/Source/WebCore/platform/graphics/ca/GraphicsLayerCA.h

@@ -158 +158 @@
         bool ancestorHadChanges { false };
         bool ancestorHasTransformAnimation { false };
+        bool ancestorStartedOrEndedTransformAnimation { false };
         bool ancestorWithTransformAnimationIntersectsCoverageRect { false };
         bool ancestorIsViewportConstrained { false };