WebCore/RenderLayerCompositor.h

   1 /*
   2  * Copyright (C) 2009 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef RenderLayerCompositor_h
  27 #define RenderLayerCompositor_h
  28
  29 #include "RenderLayer.h"
  30
  31 namespace WebCore {
  32
  33 #define PROFILE_LAYER_REBUILD 0
  34
  35 class GraphicsLayer;
  36
  37 // RenderLayerCompositor manages the hierarchy of
  38 // composited RenderLayers. It determines which RenderLayers
  39 // become compositing, and creates and maintains a hierarchy of
  40 // GraphicsLayers based on the RenderLayer painting order.
  41 //
  42 // There is one RenderLayerCompositor per RenderView.
  43
  44 class RenderLayerCompositor {
  45 public:
  46
  47     RenderLayerCompositor(RenderView*);
  48     ~RenderLayerCompositor();
  49
  50     // Return true if this RenderView is in "compositing mode" (i.e. has one or more
  51     // composited RenderLayers)
  52     bool inCompositingMode() const { return m_compositing; }
  53     // This will make a compositing layer at the root automatically, and hook up to
  54     // the native view/window system.
  55     void enableCompositingMode(bool enable = true);
  56
  57     void setCompositingLayersNeedUpdate(bool needUpdate = true);
  58     bool compositingLayersNeedUpdate() const { return m_compositingLayersNeedUpdate; }
  59
  60     void scheduleViewUpdate();
  61
  62     // Rebuild the tree of compositing layers
  63     void updateCompositingLayers(RenderLayer* updateRoot = 0);
  64
  65     // Update the compositing state of the given layer. Returns true if that state changed.
  66     enum CompositingChangeRepaint { CompositingChangeRepaintNow, CompositingChangeWillRepaintLater };
  67     bool updateLayerCompositingState(RenderLayer*, CompositingChangeRepaint = CompositingChangeRepaintNow);
  68
  69     // Whether layer's backing needs a graphics layer to do clipping by an ancestor (non-stacking-context parent with overflow).
  70     bool clippedByAncestor(RenderLayer*) const;
  71     // Whether layer's backing needs a graphics layer to clip z-order children of the given layer.
  72     bool clipsCompositingDescendants(const RenderLayer*) const;
  73
  74     // Whether the given layer needs an extra 'contents' layer.
  75     bool needsContentsCompositingLayer(const RenderLayer*) const;
  76     // Return the bounding box required for compositing layer and its childern, relative to ancestorLayer.
  77     // If layerBoundingBox is not 0, on return it contains the bounding box of this layer only.
  78     IntRect calculateCompositedBounds(const RenderLayer* layer, const RenderLayer* ancestorLayer, IntRect* layerBoundingBox = 0);
  79
  80     // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
  81     void repaintOnCompositingChange(RenderLayer*);
  82
  83     // Notify us that a layer has been added or removed
  84     void layerWasAdded(RenderLayer* parent, RenderLayer* child);
  85     void layerWillBeRemoved(RenderLayer* parent, RenderLayer* child);
  86
  87     // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
  88     RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer* layer) const;
  89
  90     // Repaint parts of all composited layers that intersect the given absolute rectangle.
  91     void repaintCompositedLayersAbsoluteRect(const IntRect&);
  92
  93     RenderLayer* rootRenderLayer() const;
  94     GraphicsLayer* rootPlatformLayer() const;
  95
  96     void didMoveOnscreen();
  97     void willMoveOffscreen();
  98
  99     void updateRootLayerPosition();
 100
 101     // Walk the tree looking for layers with 3d transforms. Useful in case you need
 102     // to know if there is non-affine content, e.g. for drawing into an image.
 103     bool has3DContent() const;
 104
 105     void setDocumentScale(float, RenderLayer* = 0);
 106
 107 private:
 108     // Whether the given RL needs a compositing layer.
 109     bool needsToBeComposited(const RenderLayer*) const;
 110     // Whether the layer has an intrinsic need for compositing layer.
 111     bool requiresCompositingLayer(const RenderLayer*) const;
 112
 113     // Repaint the given rect (which is layer's coords), and regions of child layers that intersect that rect.
 114     void recursiveRepaintLayerRect(RenderLayer* layer, const IntRect& rect);
 115
 116     void computeCompositingRequirements(RenderLayer*, struct CompositingState&);
 117     void rebuildCompositingLayerTree(RenderLayer* layer, struct CompositingState&);
 118
 119     // Hook compositing layers together
 120     void setCompositingParent(RenderLayer* childLayer, RenderLayer* parentLayer);
 121     void removeCompositedChildren(RenderLayer*);
 122
 123     void parentInRootLayer(RenderLayer*);
 124
 125     bool layerHas3DContent(const RenderLayer*) const;
 126
 127     void ensureRootPlatformLayer();
 128
 129     // Whether a running transition or animation enforces the need for a compositing layer.
 130     static bool requiresCompositingForAnimation(RenderObject*);
 131     static bool requiresCompositingForTransform(RenderObject*);
 132
 133 private:
 134     RenderView* m_renderView;
 135     GraphicsLayer* m_rootPlatformLayer;
 136     bool m_compositing;
 137     bool m_rootLayerAttached;
 138     bool m_compositingLayersNeedUpdate;
 139 #if PROFILE_LAYER_REBUILD
 140     int m_rootLayerUpdateCount;
 141 #endif
 142 };
 143
 144
 145 } // namespace WebCore
 146
 147 #endif // RenderLayerCompositor_h