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26 #ifndef RenderLayerCompositor_h
27 #define RenderLayerCompositor_h
29 #include "RenderLayer.h"
30 #include "RenderLayerBacking.h"
34 #define PROFILE_LAYER_REBUILD 0
37 class RenderEmbeddedObject;
43 enum CompositingUpdateType {
44 CompositingUpdateAfterLayoutOrStyleChange,
45 CompositingUpdateOnPaitingOrHitTest,
46 CompositingUpdateOnScroll
49 // RenderLayerCompositor manages the hierarchy of
50 // composited RenderLayers. It determines which RenderLayers
51 // become compositing, and creates and maintains a hierarchy of
52 // GraphicsLayers based on the RenderLayer painting order.
54 // There is one RenderLayerCompositor per RenderView.
56 class RenderLayerCompositor {
58 RenderLayerCompositor(RenderView*);
59 ~RenderLayerCompositor();
61 // Return true if this RenderView is in "compositing mode" (i.e. has one or more
62 // composited RenderLayers)
63 bool inCompositingMode() const { return m_compositing; }
64 // This will make a compositing layer at the root automatically, and hook up to
65 // the native view/window system.
66 void enableCompositingMode(bool enable = true);
68 // Returns true if the accelerated compositing is enabled
69 bool hasAcceleratedCompositing() const { return m_hasAcceleratedCompositing; }
71 bool showDebugBorders() const { return m_showDebugBorders; }
72 bool showRepaintCounter() const { return m_showRepaintCounter; }
74 // Copy the accelerated compositing related flags from Settings
75 void cacheAcceleratedCompositingFlags();
77 // Called when the layer hierarchy needs to be updated (compositing layers have been
78 // created, destroyed or re-parented).
79 void setCompositingLayersNeedRebuild(bool needRebuild = true);
80 bool compositingLayersNeedRebuild() const { return m_compositingLayersNeedRebuild; }
82 // Controls whether or not to consult geometry when deciding which layers need
83 // to be composited. Defaults to true.
84 void setCompositingConsultsOverlap(bool b) { m_compositingConsultsOverlap = b; }
85 bool compositingConsultsOverlap() const { return m_compositingConsultsOverlap; }
89 // Rebuild the tree of compositing layers
90 void updateCompositingLayers(CompositingUpdateType = CompositingUpdateAfterLayoutOrStyleChange, RenderLayer* updateRoot = 0);
91 // This is only used when state changes and we do not exepect a style update or layout to happen soon (e.g. when
92 // we discover that an iframe is overlapped during painting).
93 void scheduleCompositingLayerUpdate();
94 bool compositingLayerUpdatePending() const;
96 // Update the compositing state of the given layer. Returns true if that state changed.
97 enum CompositingChangeRepaint { CompositingChangeRepaintNow, CompositingChangeWillRepaintLater };
98 bool updateLayerCompositingState(RenderLayer*, CompositingChangeRepaint = CompositingChangeRepaintNow);
100 // Update the geometry for compositing children of compositingAncestor.
101 void updateCompositingDescendantGeometry(RenderLayer* compositingAncestor, RenderLayer* layer, RenderLayerBacking::UpdateDepth);
103 // Whether layer's backing needs a graphics layer to do clipping by an ancestor (non-stacking-context parent with overflow).
104 bool clippedByAncestor(RenderLayer*) const;
105 // Whether layer's backing needs a graphics layer to clip z-order children of the given layer.
106 bool clipsCompositingDescendants(const RenderLayer*) const;
108 // Whether the given layer needs an extra 'contents' layer.
109 bool needsContentsCompositingLayer(const RenderLayer*) const;
110 // Return the bounding box required for compositing layer and its childern, relative to ancestorLayer.
111 // If layerBoundingBox is not 0, on return it contains the bounding box of this layer only.
112 IntRect calculateCompositedBounds(const RenderLayer* layer, const RenderLayer* ancestorLayer);
114 // Repaint the appropriate layers when the given RenderLayer starts or stops being composited.
115 void repaintOnCompositingChange(RenderLayer*);
117 // Notify us that a layer has been added or removed
118 void layerWasAdded(RenderLayer* parent, RenderLayer* child);
119 void layerWillBeRemoved(RenderLayer* parent, RenderLayer* child);
121 // Get the nearest ancestor layer that has overflow or clip, but is not a stacking context
122 RenderLayer* enclosingNonStackingClippingLayer(const RenderLayer* layer) const;
124 // Repaint parts of all composited layers that intersect the given absolute rectangle.
125 void repaintCompositedLayersAbsoluteRect(const IntRect&);
127 RenderLayer* rootRenderLayer() const;
128 GraphicsLayer* rootPlatformLayer() const;
130 enum RootLayerAttachment {
132 RootLayerAttachedViaChromeClient,
133 RootLayerAttachedViaEnclosingIframe
136 RootLayerAttachment rootLayerAttachment() const { return m_rootLayerAttachment; }
137 void updateRootLayerAttachment();
138 void updateRootLayerPosition();
140 void didMoveOnscreen();
141 void willMoveOffscreen();
143 void didStartAcceleratedAnimation();
146 // Use by RenderVideo to ask if it should try to use accelerated compositing.
147 bool canAccelerateVideoRendering(RenderVideo*) const;
150 // Walk the tree looking for layers with 3d transforms. Useful in case you need
151 // to know if there is non-affine content, e.g. for drawing into an image.
152 bool has3DContent() const;
154 // Most platforms connect compositing layer trees between iframes and their parent document.
155 // Some (currently just Mac) allow iframes to do their own compositing.
156 static bool allowsIndependentlyCompositedIFrames(const FrameView*);
157 bool shouldPropagateCompositingToEnclosingIFrame() const;
159 // FIXME: This should be a RenderIFrame*
160 HTMLFrameOwnerElement* enclosingIFrameElement() const;
162 static RenderLayerCompositor* iframeContentsCompositor(RenderIFrame*);
163 // Return true if the layers changed.
164 static bool parentIFrameContentLayers(RenderIFrame*);
166 // Update the geometry of the layers used for clipping and scrolling in frames.
167 void frameViewDidChangeSize(const IntPoint& contentsOffset = IntPoint());
168 void frameViewDidScroll(const IntPoint& = IntPoint());
170 String layerTreeAsText();
173 // Whether the given RL needs a compositing layer.
174 bool needsToBeComposited(const RenderLayer*) const;
175 // Whether the layer has an intrinsic need for compositing layer.
176 bool requiresCompositingLayer(const RenderLayer*) const;
177 // Whether the layer could ever be composited.
178 bool canBeComposited(const RenderLayer*) const;
180 // Make or destroy the backing for this layer; returns true if backing changed.
181 bool updateBacking(RenderLayer*, CompositingChangeRepaint shouldRepaint);
183 // Repaint the given rect (which is layer's coords), and regions of child layers that intersect that rect.
184 void recursiveRepaintLayerRect(RenderLayer* layer, const IntRect& rect);
186 typedef HashMap<RenderLayer*, IntRect> OverlapMap;
187 static void addToOverlapMap(OverlapMap&, RenderLayer*, IntRect& layerBounds, bool& boundsComputed);
188 static bool overlapsCompositedLayers(OverlapMap&, const IntRect& layerBounds);
190 void updateCompositingLayersTimerFired(Timer<RenderLayerCompositor>*);
192 // Returns true if any layer's compositing changed
193 void computeCompositingRequirements(RenderLayer*, OverlapMap*, struct CompositingState&, bool& layersChanged);
195 // Recurses down the tree, parenting descendant compositing layers and collecting an array of child layers for the current compositing layer.
196 void rebuildCompositingLayerTree(RenderLayer* layer, const struct CompositingState&, Vector<GraphicsLayer*>& childGraphicsLayersOfEnclosingLayer);
198 // Recurses down the tree, updating layer geometry only.
199 void updateLayerTreeGeometry(RenderLayer*);
201 // Hook compositing layers together
202 void setCompositingParent(RenderLayer* childLayer, RenderLayer* parentLayer);
203 void removeCompositedChildren(RenderLayer*);
205 bool layerHas3DContent(const RenderLayer*) const;
207 void ensureRootPlatformLayer();
208 void destroyRootPlatformLayer();
210 void attachRootPlatformLayer(RootLayerAttachment);
211 void detachRootPlatformLayer();
213 void rootLayerAttachmentChanged();
215 void scheduleNeedsStyleRecalc(Element*);
216 void notifyIFramesOfCompositingChange();
218 // Whether a running transition or animation enforces the need for a compositing layer.
219 bool requiresCompositingForAnimation(RenderObject*) const;
220 bool requiresCompositingForTransform(RenderObject*) const;
221 bool requiresCompositingForVideo(RenderObject*) const;
222 bool requiresCompositingForCanvas(RenderObject*) const;
223 bool requiresCompositingForPlugin(RenderObject*) const;
224 bool requiresCompositingForIFrame(RenderObject*) const;
225 bool requiresCompositingWhenDescendantsAreCompositing(RenderObject*) const;
227 #if PLATFORM(ANDROID)
228 // Whether we are on a mobile site
229 bool requiresCompositingForMobileSites(const RenderLayer* layer) const;
232 bool requiresScrollLayer(RootLayerAttachment) const;
235 RenderView* m_renderView;
236 OwnPtr<GraphicsLayer> m_rootPlatformLayer;
237 Timer<RenderLayerCompositor> m_updateCompositingLayersTimer;
239 bool m_hasAcceleratedCompositing;
240 bool m_showDebugBorders;
241 bool m_showRepaintCounter;
242 bool m_compositingConsultsOverlap;
244 // When true, we have to wait until layout has happened before we can decide whether to enter compositing mode,
245 // because only then do we know the final size of plugins and iframes.
246 // FIXME: once set, this is never cleared.
247 mutable bool m_compositingDependsOnGeometry;
250 bool m_compositingLayersNeedRebuild;
252 RootLayerAttachment m_rootLayerAttachment;
254 // Enclosing clipping layer for iframe content
255 OwnPtr<GraphicsLayer> m_clipLayer;
256 OwnPtr<GraphicsLayer> m_scrollLayer;
258 #if PROFILE_LAYER_REBUILD
259 int m_rootLayerUpdateCount;
264 } // namespace WebCore
266 #endif // RenderLayerCompositor_h