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/rendering/RenderObject.h" 30 #include "platform/PlatformWheelEvent.h" 31 #include "platform/geometry/IntRect.h" 32 #include "platform/scroll/ScrollTypes.h" 33 #include "wtf/text/WTFString.h" 34 35 namespace blink { 36 class WebLayer; 37 class WebScrollbarLayer; 38 } 39 40 namespace WebCore { 41 42 typedef unsigned MainThreadScrollingReasons; 43 44 class Document; 45 class LocalFrame; 46 class FrameView; 47 class GraphicsLayer; 48 class Page; 49 class Region; 50 class ScrollableArea; 51 class ViewportConstraints; 52 53 class ScrollingCoordinator { 54 public: 55 ~ScrollingCoordinator(); 56 57 static PassOwnPtr<ScrollingCoordinator> create(Page*); 58 59 void willBeDestroyed(); 60 61 // Return whether this scrolling coordinator handles scrolling for the given frame view. 62 bool coordinatesScrollingForFrameView(FrameView*) const; 63 64 // Called when any frame has done its layout. 65 void notifyLayoutUpdated(); 66 67 void updateAfterCompositingChangeIfNeeded(); 68 69 void updateHaveWheelEventHandlers(); 70 void updateHaveScrollEventHandlers(); 71 72 // Should be called whenever the slow repaint objects counter changes between zero and one. 73 void frameViewHasSlowRepaintObjectsDidChange(FrameView*); 74 75 // Should be called whenever the set of fixed objects changes. 76 void frameViewFixedObjectsDidChange(FrameView*); 77 78 // Should be called whenever the root layer for the given frame view changes. 79 void frameViewRootLayerDidChange(FrameView*); 80 81 #if OS(MACOSX) 82 // Dispatched by the scrolling tree during handleWheelEvent. This is required as long as scrollbars are painted on the main thread. 83 void handleWheelEventPhase(PlatformWheelEventPhase); 84 #endif 85 86 enum MainThreadScrollingReasonFlags { 87 HasSlowRepaintObjects = 1 << 0, 88 HasViewportConstrainedObjectsWithoutSupportingFixedLayers = 1 << 1, 89 HasNonLayerViewportConstrainedObjects = 1 << 2, 90 }; 91 92 MainThreadScrollingReasons mainThreadScrollingReasons() const; shouldUpdateScrollLayerPositionOnMainThread()93 bool shouldUpdateScrollLayerPositionOnMainThread() const { return mainThreadScrollingReasons() != 0; } 94 95 PassOwnPtr<blink::WebScrollbarLayer> createSolidColorScrollbarLayer(ScrollbarOrientation, int thumbThickness, int trackStart, bool isLeftSideVerticalScrollbar); 96 97 void willDestroyScrollableArea(ScrollableArea*); 98 // Returns true if the coordinator handled this change. 99 bool scrollableAreaScrollLayerDidChange(ScrollableArea*); 100 void scrollableAreaScrollbarLayerDidChange(ScrollableArea*, ScrollbarOrientation); 101 void setLayerIsContainerForFixedPositionLayers(GraphicsLayer*, bool); 102 void updateLayerPositionConstraint(RenderLayer*); 103 void touchEventTargetRectsDidChange(); 104 void willDestroyRenderLayer(RenderLayer*); 105 106 void updateScrollParentForGraphicsLayer(GraphicsLayer* child, RenderLayer* parent); 107 void updateClipParentForGraphicsLayer(GraphicsLayer* child, RenderLayer* parent); 108 109 static String mainThreadScrollingReasonsAsText(MainThreadScrollingReasons); 110 String mainThreadScrollingReasonsAsText() const; 111 Region computeShouldHandleScrollGestureOnMainThreadRegion(const LocalFrame*, const IntPoint& frameLocation) const; 112 113 void updateTouchEventTargetRectsIfNeeded(); 114 115 // For testing purposes only. This ScrollingCoordinator is reused between layout test, and must be reset 116 // for the results to be valid. 117 void reset(); 118 119 protected: 120 explicit ScrollingCoordinator(Page*); 121 122 bool isForMainFrame(ScrollableArea*) const; 123 124 Page* m_page; 125 126 // Dirty flags used to idenfity what really needs to be computed after compositing is updated. 127 bool m_scrollGestureRegionIsDirty; 128 bool m_touchEventTargetRectsAreDirty; 129 bool m_shouldScrollOnMainThreadDirty; 130 131 private: shouldUpdateAfterCompositingChange()132 bool shouldUpdateAfterCompositingChange() const { return m_scrollGestureRegionIsDirty || m_touchEventTargetRectsAreDirty || frameViewIsDirty(); } 133 134 void setShouldUpdateScrollLayerPositionOnMainThread(MainThreadScrollingReasons); 135 136 bool hasVisibleSlowRepaintViewportConstrainedObjects(FrameView*) const; 137 138 bool touchHitTestingEnabled() const; 139 void setShouldHandleScrollGestureOnMainThreadRegion(const Region&); 140 void setTouchEventTargetRects(LayerHitTestRects&); 141 void computeTouchEventTargetRects(LayerHitTestRects&); 142 143 blink::WebScrollbarLayer* addWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation, PassOwnPtr<blink::WebScrollbarLayer>); 144 blink::WebScrollbarLayer* getWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation); 145 void removeWebScrollbarLayer(ScrollableArea*, ScrollbarOrientation); 146 147 bool frameViewIsDirty() const; 148 149 typedef HashMap<ScrollableArea*, OwnPtr<blink::WebScrollbarLayer> > ScrollbarMap; 150 ScrollbarMap m_horizontalScrollbars; 151 ScrollbarMap m_verticalScrollbars; 152 HashSet<const RenderLayer*> m_layersWithTouchRects; 153 bool m_wasFrameScrollable; 154 155 // This is retained for testing. 156 MainThreadScrollingReasons m_lastMainThreadScrollingReasons; 157 }; 158 159 } // namespace WebCore 160 161 #endif // ScrollingCoordinator_h 162