Changeset 137248 in webkit

Timestamp:

Dec 10, 2012, 9:54:06 PM (13 years ago)

Author:

Simon Fraser

Message:

Source/WebCore: REGRESSION (r137215): WebKit stretches and shrinks a part of screen on scroll
​https://bugs.webkit.org/show_bug.cgi?id=104626

Reviewed by Beth Dakin.

r137215 removed a compositing layer repaint on size changes. However, there
are cases where the compositing code constrains layer size by clipping
with the viewport and a clipping ancestor. When that happens, we must
invalidate the layer on a size change to avoid showing stretched or
shrunken content.

Test: compositing/repaint/clipped-layer-size-change.html

• rendering/RenderLayerBacking.cpp:

(WebCore::RenderLayerBacking::RenderLayerBacking):
(WebCore::RenderLayerBacking::updateCompositedBounds):
(WebCore::RenderLayerBacking::updateGraphicsLayerGeometry):

• rendering/RenderLayerBacking.h:

(RenderLayerBacking):

LayoutTests: REGRESSION(r137215): WebKit stretches and shrinks a part of screen on scroll
​https://bugs.webkit.org/show_bug.cgi?id=104626

Reviewed by Beth Dakin.

Testcase that scrolls an overflow area containing a compositing layer.

• compositing/repaint/clipped-layer-size-change-expected.html: Added.
• compositing/repaint/clipped-layer-size-change.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/compositing/repaint/clipped-layer-size-change-expected.html (added)
• LayoutTests/compositing/repaint/clipped-layer-size-change.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderLayerBacking.cpp (modified) (4 diffs)
• Source/WebCore/rendering/RenderLayerBacking.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2012-12-10  Simon Fraser  <simon.fraser@apple.com>
+
+        REGRESSION(r137215): WebKit stretches and shrinks a part of screen on scroll
+        https://bugs.webkit.org/show_bug.cgi?id=104626
+
+        Reviewed by Beth Dakin.
+
+        Testcase that scrolls an overflow area containing a compositing layer.
+
+        * compositing/repaint/clipped-layer-size-change-expected.html: Added.
+        * compositing/repaint/clipped-layer-size-change.html: Added.
+
 2012-12-10  Noel Gordon  <noel.gordon@gmail.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-12-10  Simon Fraser  <simon.fraser@apple.com>
+
+        REGRESSION (r137215): WebKit stretches and shrinks a part of screen on scroll
+        https://bugs.webkit.org/show_bug.cgi?id=104626
+
+        Reviewed by Beth Dakin.
+
+        r137215 removed a compositing layer repaint on size changes. However, there
+        are cases where the compositing code constrains layer size by clipping
+        with the viewport and a clipping ancestor. When that happens, we must
+        invalidate the layer on a size change to avoid showing stretched or
+        shrunken content.
+
+        Test: compositing/repaint/clipped-layer-size-change.html
+
+        * rendering/RenderLayerBacking.cpp:
+        (WebCore::RenderLayerBacking::RenderLayerBacking):
+        (WebCore::RenderLayerBacking::updateCompositedBounds):
+        (WebCore::RenderLayerBacking::updateGraphicsLayerGeometry):
+        * rendering/RenderLayerBacking.h:
+        (RenderLayerBacking):
+
 2012-12-10  Dean Jackson  <dino@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayerBacking.cpp

@@ -102 +102 @@
     , m_scrollLayerID(0)
     , m_artificiallyInflatedBounds(false)
+    , m_boundsConstrainedByClipping(false)
     , m_isMainFrameRenderViewLayer(false)
     , m_usingTiledCacheLayer(false)
@@ -367 +368 @@
 }
 
-
 void RenderLayerBacking::updateCompositedBounds()
 {
@@ -390 +390 @@
 
         layerBounds.intersect(pixelSnappedIntRect(clippingBounds));
-    }
+        m_boundsConstrainedByClipping = true;
+    } else
+        m_boundsConstrainedByClipping = false;
     
     // If the element has a transform-origin that has fixed lengths, and the renderer has zero size,
@@ -632 +634 @@
     FloatSize oldSize = m_graphicsLayer->size();
     FloatSize newSize = relativeCompositingBounds.size();
-    if (oldSize != newSize)
+    if (oldSize != newSize) {
         m_graphicsLayer->setSize(newSize);
+        // Usually invalidation will happen via layout etc, but if we've affected the layer
+        // size by constraining relative to a clipping ancestor or the viewport, we
+        // have to invalidate to avoid showing stretched content.
+        if (m_boundsConstrainedByClipping)
+            m_graphicsLayer->setNeedsDisplay();
+    }
 
     // If we have a layer that clips children, position it.

trunk/Source/WebCore/rendering/RenderLayerBacking.h

@@ -276 +276 @@
     IntRect m_compositedBounds;
 
-    bool m_artificiallyInflatedBounds;      // bounds had to be made non-zero to make transform-origin work
+    bool m_artificiallyInflatedBounds; // bounds had to be made non-zero to make transform-origin work
+    bool m_boundsConstrainedByClipping;
     bool m_isMainFrameRenderViewLayer;
     bool m_usingTiledCacheLayer;