Source/WebCore/platform/ScrollableArea.h - WebKit - Git at Google

 /*
  * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #ifndef ScrollableArea_h
 #define ScrollableArea_h

 #include "Scrollbar.h"
 #include <wtf/Vector.h>

 namespace WebCore {

 class FloatPoint;
 class GraphicsContext;
 class PlatformGestureEvent;
 class PlatformWheelEvent;
 class ScrollAnimator;
 #if USE(ACCELERATED_COMPOSITING)
 class GraphicsLayer;
 class TiledBacking;
 #endif

 class ScrollableArea {
 public:
     bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
     void scrollToOffsetWithoutAnimation(const FloatPoint&);
     void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);

     // Should be called when the scroll position changes externally, for example if the scroll layer position
     // is updated on the scrolling thread and we need to notify the main thread.
     void notifyScrollPositionChanged(const IntPoint&);

     // Allows subclasses to handle scroll position updates themselves. If this member function
     // returns true, the scrollable area won't actually update the scroll position and instead
     // expect it to happen sometime in the future.
     virtual bool requestScrollPositionUpdate(const IntPoint&) { return false; }

     bool handleWheelEvent(const PlatformWheelEvent&);

     // Functions for controlling if you can scroll past the end of the document.
     bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
     void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }

     void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
     ScrollElasticity verticalScrollElasticity() const { return static_cast<ScrollElasticity>(m_verticalScrollElasticity); }

     void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
     ScrollElasticity horizontalScrollElasticity() const { return static_cast<ScrollElasticity>(m_horizontalScrollElasticity); }

     bool inLiveResize() const { return m_inLiveResize; }
     void willStartLiveResize();
     void willEndLiveResize();

     void contentAreaWillPaint() const;
     void mouseEnteredContentArea() const;
     void mouseExitedContentArea() const;
     void mouseMovedInContentArea() const;
     void mouseEnteredScrollbar(Scrollbar*) const;
     void mouseExitedScrollbar(Scrollbar*) const;
     void contentAreaDidShow() const;
     void contentAreaDidHide() const;

     void finishCurrentScrollAnimations() const;

     void didAddVerticalScrollbar(Scrollbar*);
     void willRemoveVerticalScrollbar(Scrollbar*);
     virtual void didAddHorizontalScrollbar(Scrollbar*);
     virtual void willRemoveHorizontalScrollbar(Scrollbar*);

     virtual void contentsResized();

     bool hasOverlayScrollbars() const;
     virtual void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
     ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }

     // This getter will create a ScrollAnimator if it doesn't already exist.
     ScrollAnimator* scrollAnimator() const;

     // This getter will return null if the ScrollAnimator hasn't been created yet.
     ScrollAnimator* existingScrollAnimator() const { return m_scrollAnimator.get(); }

     const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
     bool scrollOriginChanged() const { return m_scrollOriginChanged; }

     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;
     virtual int scrollPosition(Scrollbar*) const = 0;
     virtual void invalidateScrollbar(Scrollbar*, const IntRect&);
     virtual bool isScrollCornerVisible() const = 0;
     virtual IntRect scrollCornerRect() const = 0;
     virtual void invalidateScrollCorner(const IntRect&);
     virtual void getTickmarks(Vector<IntRect>&) const { }

     // Convert points and rects between the scrollbar and its containing view.
     // The client needs to implement these in order to be aware of layout effects
     // like CSS transforms.
     virtual IntRect convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const
     {
         return scrollbar->Widget::convertToContainingView(scrollbarRect);
     }
     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const
     {
         return scrollbar->Widget::convertFromContainingView(parentRect);
     }
     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const
     {
         return scrollbar->Widget::convertToContainingView(scrollbarPoint);
     }
     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const
     {
         return scrollbar->Widget::convertFromContainingView(parentPoint);
     }

     virtual Scrollbar* horizontalScrollbar() const { return 0; }
     virtual Scrollbar* verticalScrollbar() const { return 0; }

     virtual IntPoint scrollPosition() const;
     virtual IntPoint minimumScrollPosition() const;
     virtual IntPoint maximumScrollPosition() const;
     virtual IntRect visibleContentRect(bool /*includeScrollbars*/ = false) const;
     virtual int visibleHeight() const = 0;
     virtual int visibleWidth() const = 0;
     virtual IntSize contentsSize() const = 0;
     virtual IntSize overhangAmount() const { return IntSize(); }
     virtual IntPoint lastKnownMousePosition() const { return IntPoint(); }

     virtual bool shouldSuspendScrollAnimations() const { return true; }
     virtual void scrollbarStyleChanged(int /*newStyle*/, bool /*forceUpdate*/) { }
     virtual void setVisibleScrollerThumbRect(const IntRect&) { }

     virtual bool scrollbarsCanBeActive() const = 0;

     // Note that this only returns scrollable areas that can actually be scrolled.
     virtual ScrollableArea* enclosingScrollableArea() const = 0;

     // Returns the bounding box of this scrollable area, in the coordinate system of the enclosing scroll view.
     virtual IntRect scrollableAreaBoundingBox() const = 0;

     virtual bool shouldRubberBandInDirection(ScrollDirection) const { return true; }
     virtual bool isRubberBandInProgress() const { return false; }

     virtual bool scrollAnimatorEnabled() const { return false; }

     // NOTE: Only called from Internals for testing.
     void setScrollOffsetFromInternals(const IntPoint&);

     // Let subclasses provide a way of asking for and servicing scroll
     // animations.
     virtual bool scheduleAnimation() { return false; }
     void serviceScrollAnimations();

 #if USE(ACCELERATED_COMPOSITING)
     virtual TiledBacking* tiledBacking() { return 0; }
     virtual bool usesCompositedScrolling() const { return false; }
 #endif

     virtual void reportMemoryUsage(MemoryObjectInfo*) const;

 protected:
     ScrollableArea();
     virtual ~ScrollableArea();

     void setScrollOrigin(const IntPoint&);
     void resetScrollOriginChanged() { m_scrollOriginChanged = false; }

     virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
     virtual void invalidateScrollCornerRect(const IntRect&) = 0;

 #if USE(ACCELERATED_COMPOSITING)
     virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
     virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; }
     virtual GraphicsLayer* layerForScrollCorner() const { return 0; }
 #if ENABLE(RUBBER_BANDING)
     virtual GraphicsLayer* layerForOverhangAreas() const { return 0; }
 #endif
 #endif
     bool hasLayerForHorizontalScrollbar() const;
     bool hasLayerForVerticalScrollbar() const;
     bool hasLayerForScrollCorner() const;

 private:
     void scrollPositionChanged(const IntPoint&);

     // NOTE: Only called from the ScrollAnimator.
     friend class ScrollAnimator;
     void setScrollOffsetFromAnimation(const IntPoint&);

     // This function should be overriden by subclasses to perform the actual
     // scroll of the content.
     virtual void setScrollOffset(const IntPoint&) = 0;

     mutable OwnPtr<ScrollAnimator> m_scrollAnimator;
     unsigned m_constrainsScrollingToContentEdge : 1;

     unsigned m_inLiveResize : 1;

     unsigned m_verticalScrollElasticity : 2; // ScrollElasticity
     unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity

     unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle

     unsigned m_scrollOriginChanged : 1;

     // There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis
     // if there is any reversed direction or writing-mode. The combinations are:
     // writing-mode / direction     scrollOrigin.x() set    scrollOrigin.y() set
     // horizontal-tb / ltr          NO                      NO
     // horizontal-tb / rtl          YES                     NO
     // horizontal-bt / ltr          NO                      YES
     // horizontal-bt / rtl          YES                     YES
     // vertical-lr / ltr            NO                      NO
     // vertical-lr / rtl            NO                      YES
     // vertical-rl / ltr            YES                     NO
     // vertical-rl / rtl            YES                     YES
     IntPoint m_scrollOrigin;
 };

 } // namespace WebCore

 #endif // ScrollableArea_h
	/*
	* Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#ifndef ScrollableArea_h
	#define ScrollableArea_h

	#include "Scrollbar.h"
	#include <wtf/Vector.h>

	namespace WebCore {

	class FloatPoint;
	class GraphicsContext;
	class PlatformGestureEvent;
	class PlatformWheelEvent;
	class ScrollAnimator;
	#if USE(ACCELERATED_COMPOSITING)
	class GraphicsLayer;
	class TiledBacking;
	#endif

	class ScrollableArea {
	public:
	bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
	void scrollToOffsetWithoutAnimation(const FloatPoint&);
	void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);

	// Should be called when the scroll position changes externally, for example if the scroll layer position
	// is updated on the scrolling thread and we need to notify the main thread.
	void notifyScrollPositionChanged(const IntPoint&);

	// Allows subclasses to handle scroll position updates themselves. If this member function
	// returns true, the scrollable area won't actually update the scroll position and instead
	// expect it to happen sometime in the future.
	virtual bool requestScrollPositionUpdate(const IntPoint&) { return false; }

	bool handleWheelEvent(const PlatformWheelEvent&);

	// Functions for controlling if you can scroll past the end of the document.
	bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
	void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }

	void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
	ScrollElasticity verticalScrollElasticity() const { return static_cast<ScrollElasticity>(m_verticalScrollElasticity); }

	void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
	ScrollElasticity horizontalScrollElasticity() const { return static_cast<ScrollElasticity>(m_horizontalScrollElasticity); }

	bool inLiveResize() const { return m_inLiveResize; }
	void willStartLiveResize();
	void willEndLiveResize();

	void contentAreaWillPaint() const;
	void mouseEnteredContentArea() const;
	void mouseExitedContentArea() const;
	void mouseMovedInContentArea() const;
	void mouseEnteredScrollbar(Scrollbar*) const;
	void mouseExitedScrollbar(Scrollbar*) const;
	void contentAreaDidShow() const;
	void contentAreaDidHide() const;

	void finishCurrentScrollAnimations() const;

	void didAddVerticalScrollbar(Scrollbar*);
	void willRemoveVerticalScrollbar(Scrollbar*);
	virtual void didAddHorizontalScrollbar(Scrollbar*);
	virtual void willRemoveHorizontalScrollbar(Scrollbar*);

	virtual void contentsResized();

	bool hasOverlayScrollbars() const;
	virtual void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
	ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }

	// This getter will create a ScrollAnimator if it doesn't already exist.
	ScrollAnimator* scrollAnimator() const;

	// This getter will return null if the ScrollAnimator hasn't been created yet.
	ScrollAnimator* existingScrollAnimator() const { return m_scrollAnimator.get(); }

	const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
	bool scrollOriginChanged() const { return m_scrollOriginChanged; }

	virtual bool isActive() const = 0;
	virtual int scrollSize(ScrollbarOrientation) const = 0;
	virtual int scrollPosition(Scrollbar*) const = 0;
	virtual void invalidateScrollbar(Scrollbar*, const IntRect&);
	virtual bool isScrollCornerVisible() const = 0;
	virtual IntRect scrollCornerRect() const = 0;
	virtual void invalidateScrollCorner(const IntRect&);
	virtual void getTickmarks(Vector<IntRect>&) const { }

	// Convert points and rects between the scrollbar and its containing view.
	// The client needs to implement these in order to be aware of layout effects
	// like CSS transforms.
	virtual IntRect convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntRect& scrollbarRect) const
	{
	return scrollbar->Widget::convertToContainingView(scrollbarRect);
	}
	virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntRect& parentRect) const
	{
	return scrollbar->Widget::convertFromContainingView(parentRect);
	}
	virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar* scrollbar, const IntPoint& scrollbarPoint) const
	{
	return scrollbar->Widget::convertToContainingView(scrollbarPoint);
	}
	virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar* scrollbar, const IntPoint& parentPoint) const
	{
	return scrollbar->Widget::convertFromContainingView(parentPoint);
	}

	virtual Scrollbar* horizontalScrollbar() const { return 0; }
	virtual Scrollbar* verticalScrollbar() const { return 0; }

	virtual IntPoint scrollPosition() const;
	virtual IntPoint minimumScrollPosition() const;
	virtual IntPoint maximumScrollPosition() const;
	virtual IntRect visibleContentRect(bool /includeScrollbars/ = false) const;
	virtual int visibleHeight() const = 0;
	virtual int visibleWidth() const = 0;
	virtual IntSize contentsSize() const = 0;
	virtual IntSize overhangAmount() const { return IntSize(); }
	virtual IntPoint lastKnownMousePosition() const { return IntPoint(); }

	virtual bool shouldSuspendScrollAnimations() const { return true; }
	virtual void scrollbarStyleChanged(int /newStyle/, bool /forceUpdate/) { }
	virtual void setVisibleScrollerThumbRect(const IntRect&) { }

	virtual bool scrollbarsCanBeActive() const = 0;

	// Note that this only returns scrollable areas that can actually be scrolled.
	virtual ScrollableArea* enclosingScrollableArea() const = 0;

	// Returns the bounding box of this scrollable area, in the coordinate system of the enclosing scroll view.
	virtual IntRect scrollableAreaBoundingBox() const = 0;

	virtual bool shouldRubberBandInDirection(ScrollDirection) const { return true; }
	virtual bool isRubberBandInProgress() const { return false; }

	virtual bool scrollAnimatorEnabled() const { return false; }

	// NOTE: Only called from Internals for testing.
	void setScrollOffsetFromInternals(const IntPoint&);

	// Let subclasses provide a way of asking for and servicing scroll
	// animations.
	virtual bool scheduleAnimation() { return false; }
	void serviceScrollAnimations();

	#if USE(ACCELERATED_COMPOSITING)
	virtual TiledBacking* tiledBacking() { return 0; }
	virtual bool usesCompositedScrolling() const { return false; }
	#endif

	virtual void reportMemoryUsage(MemoryObjectInfo*) const;

	protected:
	ScrollableArea();
	virtual ~ScrollableArea();

	void setScrollOrigin(const IntPoint&);
	void resetScrollOriginChanged() { m_scrollOriginChanged = false; }

	virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
	virtual void invalidateScrollCornerRect(const IntRect&) = 0;

	#if USE(ACCELERATED_COMPOSITING)
	virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
	virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; }
	virtual GraphicsLayer* layerForScrollCorner() const { return 0; }
	#if ENABLE(RUBBER_BANDING)
	virtual GraphicsLayer* layerForOverhangAreas() const { return 0; }
	#endif
	#endif
	bool hasLayerForHorizontalScrollbar() const;
	bool hasLayerForVerticalScrollbar() const;
	bool hasLayerForScrollCorner() const;

	private:
	void scrollPositionChanged(const IntPoint&);

	// NOTE: Only called from the ScrollAnimator.
	friend class ScrollAnimator;
	void setScrollOffsetFromAnimation(const IntPoint&);

	// This function should be overriden by subclasses to perform the actual
	// scroll of the content.
	virtual void setScrollOffset(const IntPoint&) = 0;

	mutable OwnPtr<ScrollAnimator> m_scrollAnimator;
	unsigned m_constrainsScrollingToContentEdge : 1;

	unsigned m_inLiveResize : 1;

	unsigned m_verticalScrollElasticity : 2; // ScrollElasticity
	unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity

	unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle

	unsigned m_scrollOriginChanged : 1;

	// There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis
	// if there is any reversed direction or writing-mode. The combinations are:
	// writing-mode / direction scrollOrigin.x() set scrollOrigin.y() set
	// horizontal-tb / ltr NO NO
	// horizontal-tb / rtl YES NO
	// horizontal-bt / ltr NO YES
	// horizontal-bt / rtl YES YES
	// vertical-lr / ltr NO NO
	// vertical-lr / rtl NO YES
	// vertical-rl / ltr YES NO
	// vertical-rl / rtl YES YES
	IntPoint m_scrollOrigin;
	};

	} // namespace WebCore

	#endif // ScrollableArea_h