1 /* 2 * Copyright (C) 2011 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. AND ITS CONTRIBUTORS ``AS IS'' 14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS 17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 23 * THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef ScrollingCoordinator_h 27 #define ScrollingCoordinator_h 28 29 #include "core/platform/PlatformWheelEvent.h" 30 #include "core/platform/ScrollTypes.h" 31 #include "core/platform/graphics/IntRect.h" 32 #include "core/rendering/RenderObject.h" 33 #include "wtf/text/WTFString.h" 34 35 namespace WebKit { 36 class WebLayer; 37 class WebScrollbarLayer; 38 } 39 40 namespace WebCore { 41 42 typedef unsigned MainThreadScrollingReasons; 43 44 class Document; 45 class Frame; 46 class FrameView; 47 class GraphicsLayer; 48 class Page; 49 class Region; 50 class ScrollableArea; 51 class ViewportConstraints; 52 53 class ScrollingCoordinator : public RefCounted<ScrollingCoordinator> { 54 public: 55 static PassRefPtr<ScrollingCoordinator> create(Page*); 56 ~ScrollingCoordinator(); 57 58 void pageDestroyed(); 59 60 // Return whether this scrolling coordinator handles scrolling for the given frame view. 61 bool coordinatesScrollingForFrameView(FrameView*) const; 62 63 // Should be called whenever the given frame view has been laid out. 64 void frameViewLayoutUpdated(FrameView*); 65 66 // Should be called whenever a wheel event handler is added or removed in the 67 // frame view's underlying document. 68 void frameViewWheelEventHandlerCountChanged(FrameView*); 69 70 // Should be called whenever the slow repaint objects counter changes between zero and one. 71 void frameViewHasSlowRepaintObjectsDidChange(FrameView*); 72 73 // Should be called whenever the set of fixed objects changes. 74 void frameViewFixedObjectsDidChange(FrameView*); 75 76 // Should be called whenever the root layer for the given frame view changes. 77 void frameViewRootLayerDidChange(FrameView*); 78 79 #if OS(DARWIN) 80 // Dispatched by the scrolling tree during handleWheelEvent. This is required as long as scrollbars are painted on the main thread. 81 void handleWheelEventPhase(PlatformWheelEventPhase); 82 #endif 83 84 enum MainThreadScrollingReasonFlags { 85 HasSlowRepaintObjects = 1 << 0, 86 HasViewportConstrainedObjectsWithoutSupportingFixedLayers = 1 << 1, 87 HasNonLayerViewportConstrainedObjects = 1 << 2, 88 }; 89 90 MainThreadScrollingReasons mainThreadScrollingReasons() const; 91 bool shouldUpdateScrollLayerPositionOnMainThread() const { return mainThreadScrollingReasons() != 0; } 92 93 void willDestroyScrollableArea(ScrollableArea*); 94 // Returns true if the coordinator handled this change. 95 bool scrollableAreaScrollLayerDidChange(ScrollableArea*); 96 void scrollableAreaScrollbarLayerDidChange(ScrollableArea*, ScrollbarOrientation); 97 void setLayerIsContainerForFixedPositionLayers(GraphicsLayer*, bool); 98 void updateLayerPositionConstraint(RenderLayer*); 99 void touchEventTargetRectsDidChange(const Document*); 100 101 static String mainThreadScrollingReasonsAsText(MainThreadScrollingReasons); 102 String mainThreadScrollingReasonsAsText() const; 103 Region computeShouldHandleScrollGestureOnMainThreadRegion(const Frame*, const IntPoint& frameLocation) const; 104 105 class TouchEventTargetRectsObserver { 106 public: 107 virtual void touchEventTargetRectsChanged(const LayerHitTestRects&) = 0; 108 }; 109 110 void addTouchEventTargetRectsObserver(TouchEventTargetRectsObserver*); 111 void removeTouchEventTargetRectsObserver(TouchEventTargetRectsObserver*); 112 113 protected: 114 explicit ScrollingCoordinator(Page*); 115 116 static GraphicsLayer* scrollLayerForScrollableArea(ScrollableArea*); 117 static GraphicsLayer* horizontalScrollbarLayerForScrollableArea(ScrollableArea*); 118 static GraphicsLayer* verticalScrollbarLayerForScrollableArea(ScrollableArea*); 119 bool isForMainFrame(ScrollableArea*) const; 120 121 unsigned computeCurrentWheelEventHandlerCount(); 122 GraphicsLayer* scrollLayerForFrameView(FrameView*); 123 GraphicsLayer* counterScrollingLayerForFrameView(FrameView*); 124 125 Page* m_page; 126 127 private: 128 void recomputeWheelEventHandlerCountForFrameView(FrameView*); 129 void setShouldUpdateScrollLayerPositionOnMainThread(MainThreadScrollingReasons); 130 131 bool hasVisibleSlowRepaintViewportConstrainedObjects(FrameView*) const; 132 void updateShouldUpdateScrollLayerPositionOnMainThread(); 133 134 static WebKit::WebLayer* scrollingWebLayerForScrollableArea(ScrollableArea*); 135 136 bool touchHitTestingEnabled() const; 137 void setShouldHandleScrollGestureOnMainThreadRegion(const Region&); 138 void setTouchEventTargetRects(const LayerHitTestRects&); 139 void computeTouchEventTargetRects(LayerHitTestRects&); 140 void setWheelEventHandlerCount(unsigned); 141 142 WebKit::WebScrollbarLayer* addWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation, PassOwnPtr<WebKit::WebScrollbarLayer>); 143 WebKit::WebScrollbarLayer* getWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation); 144 void removeWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation); 145 146 147 typedef HashMap<ScrollableArea*, OwnPtr<WebKit::WebScrollbarLayer> > ScrollbarMap; 148 ScrollbarMap m_horizontalScrollbars; 149 ScrollbarMap m_verticalScrollbars; 150 151 HashSet<TouchEventTargetRectsObserver*> m_touchEventTargetRectsObservers; 152 }; 153 154 } // namespace WebCore 155 156 #endif // ScrollingCoordinator_h 157