Changeset 158934 in webkit

Timestamp:

Nov 8, 2013, 11:38:58 AM (11 years ago)

Author:

Simon Fraser

Message:

Left sidebar on cubic-bezier.com flickers
​https://bugs.webkit.org/show_bug.cgi?id=123128

Source/WebCore:

Reviewed by Dean Jackson.

The logic that determined whether position:fixed elements outside the viewport
should be composited was incorrect if the fixed element also had a transform.

layer.calculateLayerBounds() only takes into account painted transforms (since they
affect layer bounds). So we need to compute the bounds relative to the layer
itself, then use localToContainerQuad() to map them to document coordinates,
but only to the RenderView so that we don't hit the page scale transform.

Tests: compositing/layer-creation/fixed-position-transformed-into-view.html

compositing/layer-creation/fixed-position-transformed-outside-view.html

• rendering/RenderLayerCompositor.cpp:

(WebCore::RenderLayerCompositor::requiresCompositingForPosition):

LayoutTests:

Reviewed by Dean Jackson.

Tests with transformed, fixed elements which dump the layer tree to see
which layers get composited.

• compositing/layer-creation/fixed-position-transformed-into-view-expected.txt: Added.
• compositing/layer-creation/fixed-position-transformed-into-view.html: Added.
• compositing/layer-creation/fixed-position-transformed-outside-view-expected.txt: Added.
• compositing/layer-creation/fixed-position-transformed-outside-view.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/compositing/layer-creation/fixed-position-transformed-into-view-expected.txt (added)
• LayoutTests/compositing/layer-creation/fixed-position-transformed-into-view.html (added)
• LayoutTests/compositing/layer-creation/fixed-position-transformed-outside-view-expected.txt (added)
• LayoutTests/compositing/layer-creation/fixed-position-transformed-outside-view.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderLayerCompositor.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog ¶

@@ +1 @@
+2013-11-08  Simon Fraser  <simon.fraser@apple.com>
+
+        Left sidebar on cubic-bezier.com flickers
+        https://bugs.webkit.org/show_bug.cgi?id=123128
+
+        Reviewed by Dean Jackson.
+        
+        Tests with transformed, fixed elements which dump the layer tree to see
+        which layers get composited.
+
+        * compositing/layer-creation/fixed-position-transformed-into-view-expected.txt: Added.
+        * compositing/layer-creation/fixed-position-transformed-into-view.html: Added.
+        * compositing/layer-creation/fixed-position-transformed-outside-view-expected.txt: Added.
+        * compositing/layer-creation/fixed-position-transformed-outside-view.html: Added.
+
 2013-11-08  Oliver Hunt  <oliver@apple.com>
 

trunk/Source/WebCore/ChangeLog ¶

@@ +1 @@
+2013-11-08  Simon Fraser  <simon.fraser@apple.com>
+
+        Left sidebar on cubic-bezier.com flickers
+        https://bugs.webkit.org/show_bug.cgi?id=123128
+
+        Reviewed by Dean Jackson.
+        
+        The logic that determined whether position:fixed elements outside the viewport
+        should be composited was incorrect if the fixed element also had a transform.
+        
+        layer.calculateLayerBounds() only takes into account painted transforms (since they
+        affect layer bounds). So we need to compute the bounds relative to the layer
+        itself, then use localToContainerQuad() to map them to document coordinates,
+        but only to the RenderView so that we don't hit the page scale transform.
+
+        Tests: compositing/layer-creation/fixed-position-transformed-into-view.html
+               compositing/layer-creation/fixed-position-transformed-outside-view.html
+
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::requiresCompositingForPosition):
+
 2013-11-08  Martin Robinson  <mrobinson@igalia.com>
 

trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp ¶

@@ -2338 +2338 @@
     // Fixed position elements that are invisible in the current view don't get their own layer.
     LayoutRect viewBounds = m_renderView.frameView().viewportConstrainedVisibleContentRect();
-    LayoutRect layerBounds = layer.calculateLayerBounds(&rootRenderLayer(), 0, RenderLayer::DefaultCalculateLayerBoundsFlags
+    LayoutRect layerBounds = layer.calculateLayerBounds(&layer, 0, RenderLayer::UseLocalClipRectIfPossible | RenderLayer::IncludeLayerFilterOutsets | RenderLayer::UseFragmentBoxes
         | RenderLayer::ExcludeHiddenDescendants | RenderLayer::DontConstrainForMask | RenderLayer::IncludeCompositedDescendants);
-    if (!viewBounds.intersects(enclosingIntRect(layerBounds))) {
+    // Map to m_renderView to ignore page scale.
+    FloatRect absoluteBounds = layer.renderer().localToContainerQuad(FloatRect(layerBounds), &m_renderView).boundingBox();
+    if (!viewBounds.intersects(enclosingIntRect(absoluteBounds))) {
         if (viewportConstrainedNotCompositedReason)
             *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;