Layer bounds are incorrect for sharing layers that paint with transforms
[WebKit-https.git] / Source / WebCore / ChangeLog
index d53874b..c7c8dca 100644 (file)
@@ -1,5 +1,70 @@
 2019-05-11  Simon Fraser  <simon.fraser@apple.com>
 
+        Layer bounds are incorrect for sharing layers that paint with transforms
+        https://bugs.webkit.org/show_bug.cgi?id=197768
+        <rdar://problem/50695493>
+
+        Reviewed by Zalan Bujtas.
+
+        We don't need to traverse shared layers if the backing-provider has overflow clip,
+        because we know they are containing-block descendants and therefore clipped.
+
+        Note tha the CSS "clip" property doesn't guarantee this, because the clip rect
+        can be larger than the element, so in that case we just traverse shared layers.
+
+        Tests: compositing/shared-backing/sharing-bounds-clip.html
+               compositing/shared-backing/sharing-bounds-non-clipping-shared-layer.html
+               compositing/shared-backing/sharing-bounds-transformed-sharing-layer.html
+               compositing/shared-backing/sharing-bounds.html
+
+        * rendering/RenderLayerBacking.cpp:
+        (WebCore::RenderLayerBacking::updateCompositedBounds):
+
+2019-05-11  Simon Fraser  <simon.fraser@apple.com>
+
+        Translucent gradient rendering bug due to will-change transform
+        https://bugs.webkit.org/show_bug.cgi?id=197654
+        <rdar://problem/50547664>
+
+        Reviewed by Dean Jackson.
+        
+        We failed to re-evaluate 'contentsOpaque' when a background changed, because this
+        happened in updateGeometry() and that doesn't run for background changes.
+        
+        However, 'contentsOpaque' also requires knowing about geometry because we have to
+        turn it off when there's subpixel positioning, and updateConfiguration()
+        runs before updateGeometry().
+        
+        So compute m_hasSubpixelRounding in updateGeometry() and set contentsOpaque in
+        updateAfterDescendants().
+
+        Test: compositing/contents-opaque/background-change-to-transparent.html
+
+        * rendering/RenderLayerBacking.cpp:
+        (WebCore::RenderLayerBacking::updateConfiguration):
+        (WebCore::RenderLayerBacking::updateGeometry):
+        (WebCore::RenderLayerBacking::updateAfterDescendants):
+        * rendering/RenderLayerBacking.h:
+
+2019-05-11  Simon Fraser  <simon.fraser@apple.com>
+
+        When the scroller hosting a shared layer becomes non-scrollable, content disappears
+        https://bugs.webkit.org/show_bug.cgi?id=197766
+        <rdar://problem/50695808>
+
+        Reviewed by Zalan Bujtas.
+
+        RenderLayerCompositor::requiresOwnBackingStore() should return true for a layer that shares
+        its backing store. We always made backing for overlap layers, so even  if the sharing layers
+        have no painted content, this should rarely be a backing store memory regression.
+
+        Test: compositing/shared-backing/overflow-scroll/sharing-layer-becomes-non-scrollable.html
+
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::requiresOwnBackingStore const):
+
+2019-05-11  Simon Fraser  <simon.fraser@apple.com>
+
         Backing-sharing layers with transforms render incorrectly
         https://bugs.webkit.org/show_bug.cgi?id=197692
         <rdar://problem/50652127>