diff options
| -rw-r--r-- | Source/WebCore/rendering/RenderLayerCompositor.cpp | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp index 33bf2f7..03f1e41 100644 --- a/Source/WebCore/rendering/RenderLayerCompositor.cpp +++ b/Source/WebCore/rendering/RenderLayerCompositor.cpp @@ -92,6 +92,10 @@ struct CompositingState { RenderLayer* m_compositingAncestor; bool m_subtreeIsCompositing; + // m_compositingBounds is only used in computeCompositingRequirements. It can be either the + // ancestor bounds or the bounds for the sibling layers which are above the composited layer. + // It is used to reject creating unnecesary layers. + IntRect m_compositingBounds; #if ENABLE(COMPOSITED_FIXED_ELEMENTS) bool m_fixedSibling; bool m_hasFixedElement; @@ -693,7 +697,10 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* layer, O if (absBounds.isEmpty()) absBounds.setSize(IntSize(1, 1)); haveComputedBounds = true; - mustOverlapCompositedLayers = overlapsCompositedLayers(*overlapMap, absBounds); + // If the current subtree is not compositing, and the layer is fully inside the current compositing bounnds, + // there is no need to do the overlap test. This reduces the total number of the composited layers. + if (compositingState.m_subtreeIsCompositing || !compositingState.m_compositingBounds.contains(absBounds)) + mustOverlapCompositedLayers = overlapsCompositedLayers(*overlapMap, absBounds); } #if ENABLE(COMPOSITED_FIXED_ELEMENTS) @@ -709,6 +716,10 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* layer, O // a compositing layer among them, so start by inheriting the compositing // ancestor with m_subtreeIsCompositing set to false. CompositingState childState(compositingState.m_compositingAncestor); + if (compositingState.m_subtreeIsCompositing) + childState.m_compositingBounds = absBounds; + else + childState.m_compositingBounds = compositingState.m_compositingBounds; #ifndef NDEBUG ++childState.m_depth; #endif @@ -729,6 +740,7 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* layer, O compositingState.m_subtreeIsCompositing = true; // This layer now acts as the ancestor for kids. childState.m_compositingAncestor = layer; + childState.m_compositingBounds = absBounds; if (overlapMap) addToOverlapMap(*overlapMap, layer, absBounds, haveComputedBounds); } |