Changeset 149084 in webkit

Timestamp:

Apr 24, 2013, 6:27:20 PM (12 years ago)

Author:

Simon Fraser

Message:

Garbage at the top of ​http://www.technologyreview.com after scrolling
​https://bugs.webkit.org/show_bug.cgi?id=114825

Source/WebCore:

Reviewed by Tim Horton.

Garbage pixels are caused by GraphicsLayerCA setting a layer to be opaque,
but then not painting anything into it. On this page, the element is
toggled to be visibility:hidden on scrolling, but RenderLayer::backgroundIsKnownToBeOpaqueInRect()
failed to consider that as something that can cause backgrounds not to be opaque.

For the bug to happen, some subtle interactions with r142012 come into play
for the layer to remain visible, hence the slightly complex testcase.

Test: compositing/contents-opaque/visibility-hidden.html

• rendering/RenderLayer.cpp:

(WebCore::RenderLayer::backgroundIsKnownToBeOpaqueInRect):

LayoutTests:

Reviewed by Tim Horton.

Test that sets visibility:hidden on an element with some complex
configuration of layer children, and dumps the layer tree to check
that the contents are not marked as opaque.

• compositing/contents-opaque/visibility-hidden-expected.txt: Added.
• compositing/contents-opaque/visibility-hidden.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/compositing/contents-opaque/visibility-hidden-expected.txt (added)
• LayoutTests/compositing/contents-opaque/visibility-hidden.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderLayer.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2013-04-24  Simon Fraser  <simon.fraser@apple.com>
+
+        Garbage at the top of http://www.technologyreview.com after scrolling
+        https://bugs.webkit.org/show_bug.cgi?id=114825
+
+        Reviewed by Tim Horton.
+        
+        Test that sets visibility:hidden on an element with some complex
+        configuration of layer children, and dumps the layer tree to check
+        that the contents are not marked as opaque.
+
+        * compositing/contents-opaque/visibility-hidden-expected.txt: Added.
+        * compositing/contents-opaque/visibility-hidden.html: Added.
+
 2013-04-24  David Kilzer  <ddkilzer@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-04-24  Simon Fraser  <simon.fraser@apple.com>
+
+        Garbage at the top of http://www.technologyreview.com after scrolling
+        https://bugs.webkit.org/show_bug.cgi?id=114825
+
+        Reviewed by Tim Horton.
+
+        Garbage pixels are caused by GraphicsLayerCA setting a layer to be opaque,
+        but then not painting anything into it. On this page, the element is
+        toggled to be visibility:hidden on scrolling, but RenderLayer::backgroundIsKnownToBeOpaqueInRect()
+        failed to consider that as something that can cause backgrounds not to be opaque.
+        
+        For the bug to happen, some subtle interactions with r142012 come into play
+        for the layer to remain visible, hence the slightly complex testcase.
+        
+        Test: compositing/contents-opaque/visibility-hidden.html
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::backgroundIsKnownToBeOpaqueInRect):
+
 2013-04-24  Simon Fraser  <simon.fraser@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -5565 +5565 @@
         return false;
 
+    ASSERT(!m_visibleContentStatusDirty);
+    if (!hasVisibleContent())
+        return false;
+
 #if ENABLE(CSS_FILTERS)
     if (paintsWithFilters() && renderer()->style()->filter().hasFilterThatAffectsOpacity())