--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/rendering/RenderLayerCompositor.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,247 @@
+/*
+ * Copyright (C) 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef RenderLayerCompositor_h
+#define RenderLayerCompositor_h
+
+#include "RenderLayer.h"
+#include "RenderLayerBacking.h"
+
+namespace WebCore {
+
+#define PROFILE_LAYER_REBUILD 0
+
+class GraphicsLayer;
+class RenderEmbeddedObject;
+class RenderIFrame;
+#if ENABLE(VIDEO)
+class RenderVideo;
+#endif
+
+enum CompositingUpdateType {
+    CompositingUpdateAfterLayoutOrStyleChange,
+    CompositingUpdateOnPaitingOrHitTest,
+    CompositingUpdateOnScroll
+};
+
+// RenderLayerCompositor manages the hierarchy of
+// composited RenderLayers. It determines which RenderLayers
+// become compositing, and creates and maintains a hierarchy of
+// GraphicsLayers based on the RenderLayer painting order.
+// 
+// There is one RenderLayerCompositor per RenderView.
+
+class RenderLayerCompositor {
+public:
+    RenderLayerCompositor(RenderView*);
+    ~RenderLayerCompositor();
+    
+    // Return true if this RenderView is in "compositing mode" (i.e. has one or more
+    // composited RenderLayers)
+    bool inCompositingMode() const { return m_compositing; }
+    // This will make a compositing layer at the root automatically, and hook up to
+    // the native view/window system.
+    void enableCompositingMode(bool enable = true);
+    
+    // Returns true if the accelerated compositing is enabled
+    bool hasAcceleratedCompositing() const { return m_hasAcceleratedCompositing; }
+    
+    bool showDebugBorders() const { return m_showDebugBorders; }
+    bool showRepaintCounter() const { return m_showRepaintCounter; }
+    
+    // Copy the accelerated compositing related flags from Settings
+    void cacheAcceleratedCompositingFlags();
+
+    // Called when the layer hierarchy needs to be updated (compositing layers have been
+    // created, destroyed or re-parented).
+    void setCompositingLayersNeedRebuild(bool needRebuild = true);
+    bool compositingLayersNeedRebuild() const { return m_compositingLayersNeedRebuild; }
+
+    // Controls whether or not to consult geometry when deciding which layers need
+    // to be composited. Defaults to true.
+    void setCompositingConsultsOverlap(bool b) { m_compositingConsultsOverlap = b; }
+    bool compositingConsultsOverlap() const { return m_compositingConsultsOverlap; }
+    
+    void scheduleSync();
+    
+    // Rebuild the tree of compositing layers
+    void updateCompositingLayers(CompositingUpdateType = CompositingUpdateAfterLayoutOrStyleChange, RenderLayer* updateRoot = 0);
+
+    // Update the compositing state of the given layer. Returns true if that state changed.
+    enum CompositingChangeRepaint { CompositingChangeRepaintNow, CompositingChangeWillRepaintLater };
+    bool updateLayerCompositingState(RenderLayer*, CompositingChangeRepaint = CompositingChangeRepaintNow);
+
+    // Update the geometry for compositing children of compositingAncestor.
+    void updateCompositingDescendantGeometry(RenderLayer* compositingAncestor, RenderLayer* layer, RenderLayerBacking::UpdateDepth);
+    
+    // Whether layer's backing needs a graphics layer to do clipping by an ancestor (non-stacking-context parent with overflow).
+    bool clippedByAncestor(RenderLayer*) const;
+    // Whether layer's backing needs a graphics layer to clip z-order children of the given layer.
+    bool clipsCompositingDescendants(const RenderLayer*) const;
+
+    // Whether the given layer needs an extra 'contents' layer.
+    bool needsContentsCompositingLayer(const RenderLayer*) const;
+    // Return the bounding box required for compositing layer and its childern, relative to ancestorLayer.
+    // If layerBoundingBox is not 0, on return it contains the bounding box of this layer only.
+    IntRect calculateCompositedBounds(const RenderLayer* layer, const RenderLayer* ancestorLayer);
+
+    // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
+    void repaintOnCompositingChange(RenderLayer*);
+    
+    // Notify us that a layer has been added or removed
+    void layerWasAdded(RenderLayer* parent, RenderLayer* child);
+    void layerWillBeRemoved(RenderLayer* parent, RenderLayer* child);
+
+    // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
+    RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer* layer) const;
+
+    // Repaint parts of all composited layers that intersect the given absolute rectangle.
+    void repaintCompositedLayersAbsoluteRect(const IntRect&);
+
+    RenderLayer* rootRenderLayer() const;
+    GraphicsLayer* rootPlatformLayer() const;
+
+    enum RootLayerAttachment {
+        RootLayerUnattached,
+        RootLayerAttachedViaChromeClient,
+        RootLayerAttachedViaEnclosingIframe
+    };
+
+    RootLayerAttachment rootLayerAttachment() const { return m_rootLayerAttachment; }
+    void updateRootLayerAttachment();
+    void updateRootLayerPosition();
+    
+    void didMoveOnscreen();
+    void willMoveOffscreen();
+    
+    void didStartAcceleratedAnimation();
+    
+#if ENABLE(VIDEO)
+    // Use by RenderVideo to ask if it should try to use accelerated compositing.
+    bool canAccelerateVideoRendering(RenderVideo*) const;
+#endif
+
+    // Walk the tree looking for layers with 3d transforms. Useful in case you need
+    // to know if there is non-affine content, e.g. for drawing into an image.
+    bool has3DContent() const;
+    
+    // Some platforms may wish to connect compositing layer trees between iframes and
+    // their parent document.
+    bool shouldPropagateCompositingToEnclosingIFrame() const;
+
+    HTMLFrameOwnerElement* enclosingIFrameElement() const;
+
+    static RenderLayerCompositor* iframeContentsCompositor(RenderIFrame*);
+    // Return true if the layers changed.
+    static bool parentIFrameContentLayers(RenderIFrame*);
+
+    // Update the geometry of the layers used for clipping and scrolling in frames.
+    void updateContentLayerOffset(const IntPoint& contentsOffset);
+    void updateContentLayerScrollPosition(const IntPoint&);
+
+private:
+    // Whether the given RL needs a compositing layer.
+    bool needsToBeComposited(const RenderLayer*) const;
+    // Whether the layer has an intrinsic need for compositing layer.
+    bool requiresCompositingLayer(const RenderLayer*) const;
+    // Whether the layer could ever be composited.
+    bool canBeComposited(const RenderLayer*) const;
+
+    // Make or destroy the backing for this layer; returns true if backing changed.
+    bool updateBacking(RenderLayer*, CompositingChangeRepaint shouldRepaint);
+
+    // Repaint the given rect (which is layer's coords), and regions of child layers that intersect that rect.
+    void recursiveRepaintLayerRect(RenderLayer* layer, const IntRect& rect);
+
+    typedef HashMap<RenderLayer*, IntRect> OverlapMap;
+    static void addToOverlapMap(OverlapMap&, RenderLayer*, IntRect& layerBounds, bool& boundsComputed);
+    static bool overlapsCompositedLayers(OverlapMap&, const IntRect& layerBounds);
+
+    // Returns true if any layer's compositing changed
+    void computeCompositingRequirements(RenderLayer*, OverlapMap*, struct CompositingState&, bool& layersChanged);
+    
+    // Recurses down the tree, parenting descendant compositing layers and collecting an array of child layers for the current compositing layer.
+    void rebuildCompositingLayerTree(RenderLayer* layer, const struct CompositingState&, Vector<GraphicsLayer*>& childGraphicsLayersOfEnclosingLayer);
+
+    // Recurses down the tree, updating layer geometry only.
+    void updateLayerTreeGeometry(RenderLayer*);
+    
+    // Hook compositing layers together
+    void setCompositingParent(RenderLayer* childLayer, RenderLayer* parentLayer);
+    void removeCompositedChildren(RenderLayer*);
+
+    bool layerHas3DContent(const RenderLayer*) const;
+
+    void ensureRootPlatformLayer();
+    void destroyRootPlatformLayer();
+
+    void attachRootPlatformLayer(RootLayerAttachment);
+    void detachRootPlatformLayer();
+    
+    void rootLayerAttachmentChanged();
+    
+    void scheduleNeedsStyleRecalc(Element*);
+    void notifyIFramesOfCompositingChange();
+
+    // Whether a running transition or animation enforces the need for a compositing layer.
+    bool requiresCompositingForAnimation(RenderObject*) const;
+    bool requiresCompositingForTransform(RenderObject*) const;
+    bool requiresCompositingForVideo(RenderObject*) const;
+    bool requiresCompositingForCanvas(RenderObject*) const;
+    bool requiresCompositingForPlugin(RenderObject*) const;
+    bool requiresCompositingForIFrame(RenderObject*) const;
+    bool requiresCompositingWhenDescendantsAreCompositing(RenderObject*) const;
+
+private:
+    RenderView* m_renderView;
+    OwnPtr<GraphicsLayer> m_rootPlatformLayer;
+    bool m_hasAcceleratedCompositing;
+    bool m_showDebugBorders;
+    bool m_showRepaintCounter;
+    bool m_compositingConsultsOverlap;
+
+    // When true, we have to wait until layout has happened before we can decide whether to enter compositing mode,
+    // because only then do we know the final size of plugins and iframes.
+    // FIXME: once set, this is never cleared.
+    mutable bool m_compositingDependsOnGeometry;
+
+    bool m_compositing;
+    bool m_compositingLayersNeedRebuild;
+
+    RootLayerAttachment m_rootLayerAttachment;
+
+    // Enclosing clipping layer for iframe content
+    OwnPtr<GraphicsLayer> m_clipLayer;
+    OwnPtr<GraphicsLayer> m_scrollLayer;
+    
+#if PROFILE_LAYER_REBUILD
+    int m_rootLayerUpdateCount;
+#endif
+};
+
+
+} // namespace WebCore
+
+#endif // RenderLayerCompositor_h