1 /* 2 * Copyright (C) 2008, 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. ``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 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 ScrollableArea_h 27 #define ScrollableArea_h 28 29 #include "platform/PlatformExport.h" 30 #include "platform/scroll//ScrollAnimator.h" 31 #include "platform/scroll/Scrollbar.h" 32 #include "wtf/Noncopyable.h" 33 #include "wtf/Vector.h" 34 35 namespace WebCore { 36 37 class FloatPoint; 38 class GraphicsContext; 39 class GraphicsLayer; 40 class PlatformGestureEvent; 41 class PlatformWheelEvent; 42 class ScrollAnimator; 43 44 class PLATFORM_EXPORT ScrollableArea { 45 WTF_MAKE_NONCOPYABLE(ScrollableArea); 46 public: 47 static int pixelsPerLineStep(); 48 static float minFractionToStepWhenPaging(); 49 static int maxOverlapBetweenPages(); 50 51 bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1); 52 void scrollToOffsetWithoutAnimation(const FloatPoint&); 53 void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset); 54 55 // Should be called when the scroll position changes externally, for example if the scroll layer position 56 // is updated on the scrolling thread and we need to notify the main thread. 57 void notifyScrollPositionChanged(const IntPoint&); 58 59 bool handleWheelEvent(const PlatformWheelEvent&); 60 61 // Functions for controlling if you can scroll past the end of the document. 62 bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; } 63 void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; } 64 65 void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; } 66 ScrollElasticity verticalScrollElasticity() const { return static_cast<ScrollElasticity>(m_verticalScrollElasticity); } 67 68 void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; } 69 ScrollElasticity horizontalScrollElasticity() const { return static_cast<ScrollElasticity>(m_horizontalScrollElasticity); } 70 71 bool inLiveResize() const { return m_inLiveResize; } 72 void willStartLiveResize(); 73 void willEndLiveResize(); 74 75 void contentAreaWillPaint() const; 76 void mouseEnteredContentArea() const; 77 void mouseExitedContentArea() const; 78 void mouseMovedInContentArea() const; 79 void mouseEnteredScrollbar(Scrollbar*) const; 80 void mouseExitedScrollbar(Scrollbar*) const; 81 void contentAreaDidShow() const; 82 void contentAreaDidHide() const; 83 84 void finishCurrentScrollAnimations() const; 85 86 virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation); 87 virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation); 88 89 virtual void contentsResized(); 90 91 bool hasOverlayScrollbars() const; 92 void setScrollbarOverlayStyle(ScrollbarOverlayStyle); 93 ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); } 94 95 // This getter will create a ScrollAnimator if it doesn't already exist. 96 ScrollAnimator* scrollAnimator() const; 97 98 // This getter will return null if the ScrollAnimator hasn't been created yet. 99 ScrollAnimator* existingScrollAnimator() const { return m_scrollAnimator.get(); } 100 101 const IntPoint& scrollOrigin() const { return m_scrollOrigin; } 102 bool scrollOriginChanged() const { return m_scrollOriginChanged; } 103 104 virtual bool isActive() const = 0; 105 virtual int scrollSize(ScrollbarOrientation) const = 0; 106 virtual void invalidateScrollbar(Scrollbar*, const IntRect&); 107 virtual bool isScrollCornerVisible() const = 0; 108 virtual IntRect scrollCornerRect() const = 0; 109 virtual void invalidateScrollCorner(const IntRect&); 110 virtual void getTickmarks(Vector<IntRect>&) const { } 111 112 // Convert points and rects between the scrollbar and its containing view. 113 // The client needs to implement these in order to be aware of layout effects 114 // like CSS transforms. 115 virtual IntRect convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const 116 { 117 return scrollbar->Widget::convertToContainingView(scrollbarRect); 118 } 119 virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const 120 { 121 return scrollbar->Widget::convertFromContainingView(parentRect); 122 } 123 virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const 124 { 125 return scrollbar->Widget::convertToContainingView(scrollbarPoint); 126 } 127 virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const 128 { 129 return scrollbar->Widget::convertFromContainingView(parentPoint); 130 } 131 132 virtual Scrollbar* horizontalScrollbar() const { return 0; } 133 virtual Scrollbar* verticalScrollbar() const { return 0; } 134 135 // scrollPosition is relative to the scrollOrigin. i.e. If the page is RTL 136 // then scrollPosition will be negative. 137 virtual IntPoint scrollPosition() const = 0; 138 virtual IntPoint minimumScrollPosition() const = 0; 139 virtual IntPoint maximumScrollPosition() const = 0; 140 141 enum IncludeScrollbarsInRect { ExcludeScrollbars, IncludeScrollbars }; 142 virtual IntRect visibleContentRect(IncludeScrollbarsInRect = ExcludeScrollbars) const; 143 virtual int visibleHeight() const = 0; 144 virtual int visibleWidth() const = 0; 145 virtual IntSize contentsSize() const = 0; 146 virtual IntSize overhangAmount() const { return IntSize(); } 147 virtual IntPoint lastKnownMousePosition() const { return IntPoint(); } 148 149 virtual bool shouldSuspendScrollAnimations() const { return true; } 150 virtual void scrollbarStyleChanged(int /*newStyle*/, bool /*forceUpdate*/) { } 151 152 virtual bool scrollbarsCanBeActive() const = 0; 153 154 // Note that this only returns scrollable areas that can actually be scrolled. 155 virtual ScrollableArea* enclosingScrollableArea() const = 0; 156 157 // Returns the bounding box of this scrollable area, in the coordinate system of the enclosing scroll view. 158 virtual IntRect scrollableAreaBoundingBox() const = 0; 159 160 virtual bool shouldRubberBandInDirection(ScrollDirection) const { return true; } 161 virtual bool isRubberBandInProgress() const { return false; } 162 163 virtual bool scrollAnimatorEnabled() const { return false; } 164 165 // NOTE: Only called from Internals for testing. 166 void setScrollOffsetFromInternals(const IntPoint&); 167 168 IntPoint clampScrollPosition(const IntPoint&) const; 169 170 // Let subclasses provide a way of asking for and servicing scroll 171 // animations. 172 virtual bool scheduleAnimation() { return false; } 173 void serviceScrollAnimations(); 174 175 virtual bool usesCompositedScrolling() const { return false; } 176 virtual void updateNeedsCompositedScrolling() { } 177 virtual void updateHasVisibleNonLayerContent() { } 178 179 virtual bool userInputScrollable(ScrollbarOrientation) const = 0; 180 virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0; 181 182 // Convenience functions 183 int scrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? scrollPosition().x() : scrollPosition().y(); } 184 int minimumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? minimumScrollPosition().x() : minimumScrollPosition().y(); } 185 int maximumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? maximumScrollPosition().x() : maximumScrollPosition().y(); } 186 int clampScrollPosition(ScrollbarOrientation orientation, int pos) { return std::max(std::min(pos, maximumScrollPosition(orientation)), minimumScrollPosition(orientation)); } 187 188 protected: 189 ScrollableArea(); 190 virtual ~ScrollableArea(); 191 192 void setScrollOrigin(const IntPoint&); 193 void resetScrollOriginChanged() { m_scrollOriginChanged = false; } 194 195 virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0; 196 virtual void invalidateScrollCornerRect(const IntRect&) = 0; 197 198 friend class ScrollingCoordinator; 199 virtual GraphicsLayer* layerForScrolling() const { return 0; } 200 virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; } 201 virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; } 202 virtual GraphicsLayer* layerForScrollCorner() const { return 0; } 203 bool hasLayerForHorizontalScrollbar() const; 204 bool hasLayerForVerticalScrollbar() const; 205 bool hasLayerForScrollCorner() const; 206 207 private: 208 void scrollPositionChanged(const IntPoint&); 209 210 // NOTE: Only called from the ScrollAnimator. 211 friend class ScrollAnimator; 212 void setScrollOffsetFromAnimation(const IntPoint&); 213 214 // This function should be overriden by subclasses to perform the actual 215 // scroll of the content. 216 virtual void setScrollOffset(const IntPoint&) = 0; 217 218 virtual int lineStep(ScrollbarOrientation) const; 219 virtual int pageStep(ScrollbarOrientation) const = 0; 220 virtual int documentStep(ScrollbarOrientation) const; 221 virtual float pixelStep(ScrollbarOrientation) const; 222 223 mutable OwnPtr<ScrollAnimator> m_scrollAnimator; 224 unsigned m_constrainsScrollingToContentEdge : 1; 225 226 unsigned m_inLiveResize : 1; 227 228 unsigned m_verticalScrollElasticity : 2; // ScrollElasticity 229 unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity 230 231 unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle 232 233 unsigned m_scrollOriginChanged : 1; 234 235 // There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis 236 // if there is any reversed direction or writing-mode. The combinations are: 237 // writing-mode / direction scrollOrigin.x() set scrollOrigin.y() set 238 // horizontal-tb / ltr NO NO 239 // horizontal-tb / rtl YES NO 240 // horizontal-bt / ltr NO YES 241 // horizontal-bt / rtl YES YES 242 // vertical-lr / ltr NO NO 243 // vertical-lr / rtl NO YES 244 // vertical-rl / ltr YES NO 245 // vertical-rl / rtl YES YES 246 IntPoint m_scrollOrigin; 247 }; 248 249 } // namespace WebCore 250 251 #endif // ScrollableArea_h 252
