sky/engine/platform/scroll/ScrollableArea.h - mojo-tools - 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 SKY_ENGINE_PLATFORM_SCROLL_SCROLLABLEAREA_H_
 #define SKY_ENGINE_PLATFORM_SCROLL_SCROLLABLEAREA_H_

 #include "sky/engine/platform/PlatformExport.h"
 #include "sky/engine/platform/scroll/ScrollAnimator.h"
 #include "sky/engine/platform/scroll/Scrollbar.h"
 #include "sky/engine/wtf/Noncopyable.h"
 #include "sky/engine/wtf/Vector.h"

 namespace blink {

 class FloatPoint;
 class HostWindow;
 class PlatformWheelEvent;
 class ScrollAnimator;

 enum ScrollBehavior {
     ScrollBehaviorAuto,
     ScrollBehaviorInstant,
     ScrollBehaviorSmooth,
 };

 enum IncludeScrollbarsInRect {
     ExcludeScrollbars,
     IncludeScrollbars,
 };

 class PLATFORM_EXPORT ScrollableArea {
     WTF_MAKE_NONCOPYABLE(ScrollableArea);
 public:
     static int pixelsPerLineStep();
     static float minFractionToStepWhenPaging();
     static int maxOverlapBetweenPages();

     // The window that hosts the ScrollView. The ScrollView will communicate scrolls and repaints to the
     // host window in the window's coordinate space.
     virtual HostWindow* hostWindow() const = 0;

     bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
     void scrollToOffsetWithoutAnimation(const FloatPoint&);
     void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);

     static bool scrollBehaviorFromString(const String&, ScrollBehavior&);

     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); }

     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 didAddScrollbar(Scrollbar*, ScrollbarOrientation);
     void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);

     void contentsResized();

     bool hasOverlayScrollbars() const;

     // 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_animators ? m_animators->scrollAnimator.get() : 0; }

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

     // FIXME(bokan): Meaningless name, rename to isActiveFocus
     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;

     // 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*, const IntRect&) const = 0;
     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const = 0;
     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const = 0;
     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const = 0;

     virtual Scrollbar* horizontalScrollbar() const = 0;
     virtual Scrollbar* verticalScrollbar() const = 0;

     // scrollPosition is relative to the scrollOrigin. i.e. If the page is RTL
     // then scrollPosition will be negative.
     virtual IntPoint scrollPosition() const = 0;
     virtual IntPoint minimumScrollPosition() const = 0;
     virtual IntPoint maximumScrollPosition() const = 0;

     virtual IntSize contentsSize() const = 0;

     bool shouldSuspendScrollAnimations() const { return true; }

     IntPoint clampScrollPosition(const IntPoint&) const;

     // Let subclasses provide a way of asking for and servicing scroll
     // animations.
     bool scheduleAnimation();
     void serviceScrollAnimations(double monotonicTime);

     // Returns true if the GraphicsLayer tree needs to be rebuilt.
     virtual bool updateAfterCompositingChange() = 0;

     virtual bool userInputScrollable(ScrollbarOrientation) const = 0;
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0;

     int scrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? scrollPosition().x() : scrollPosition().y(); }
     int minimumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? minimumScrollPosition().x() : minimumScrollPosition().y(); }
     int maximumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? maximumScrollPosition().x() : maximumScrollPosition().y(); }
     int clampScrollPosition(ScrollbarOrientation orientation, int pos)  { return std::max(std::min(pos, maximumScrollPosition(orientation)), minimumScrollPosition(orientation)); }

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

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

 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;

     int lineStep(ScrollbarOrientation) const;
     int documentStep(ScrollbarOrientation) const;
     virtual int pageStep(ScrollbarOrientation) const = 0;
     float pixelStep(ScrollbarOrientation) const;

     struct ScrollableAreaAnimators {
         OwnPtr<ScrollAnimator> scrollAnimator;
     };

     mutable OwnPtr<ScrollableAreaAnimators> m_animators;
     unsigned m_constrainsScrollingToContentEdge : 1;

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

     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 blink

 #endif  // SKY_ENGINE_PLATFORM_SCROLL_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 SKY_ENGINE_PLATFORM_SCROLL_SCROLLABLEAREA_H_
	#define SKY_ENGINE_PLATFORM_SCROLL_SCROLLABLEAREA_H_

	#include "sky/engine/platform/PlatformExport.h"
	#include "sky/engine/platform/scroll/ScrollAnimator.h"
	#include "sky/engine/platform/scroll/Scrollbar.h"
	#include "sky/engine/wtf/Noncopyable.h"
	#include "sky/engine/wtf/Vector.h"

	namespace blink {

	class FloatPoint;
	class HostWindow;
	class PlatformWheelEvent;
	class ScrollAnimator;

	enum ScrollBehavior {
	ScrollBehaviorAuto,
	ScrollBehaviorInstant,
	ScrollBehaviorSmooth,
	};

	enum IncludeScrollbarsInRect {
	ExcludeScrollbars,
	IncludeScrollbars,
	};

	class PLATFORM_EXPORT ScrollableArea {
	WTF_MAKE_NONCOPYABLE(ScrollableArea);
	public:
	static int pixelsPerLineStep();
	static float minFractionToStepWhenPaging();
	static int maxOverlapBetweenPages();

	// The window that hosts the ScrollView. The ScrollView will communicate scrolls and repaints to the
	// host window in the window's coordinate space.
	virtual HostWindow* hostWindow() const = 0;

	bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
	void scrollToOffsetWithoutAnimation(const FloatPoint&);
	void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);

	static bool scrollBehaviorFromString(const String&, ScrollBehavior&);

	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); }

	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 didAddScrollbar(Scrollbar*, ScrollbarOrientation);
	void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);

	void contentsResized();

	bool hasOverlayScrollbars() const;

	// 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_animators ? m_animators->scrollAnimator.get() : 0; }

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

	// FIXME(bokan): Meaningless name, rename to isActiveFocus
	virtual bool isActive() const = 0;
	virtual int scrollSize(ScrollbarOrientation) const = 0;

	// 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*, const IntRect&) const = 0;
	virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const = 0;
	virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const = 0;
	virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const = 0;

	virtual Scrollbar* horizontalScrollbar() const = 0;
	virtual Scrollbar* verticalScrollbar() const = 0;

	// scrollPosition is relative to the scrollOrigin. i.e. If the page is RTL
	// then scrollPosition will be negative.
	virtual IntPoint scrollPosition() const = 0;
	virtual IntPoint minimumScrollPosition() const = 0;
	virtual IntPoint maximumScrollPosition() const = 0;

	virtual IntSize contentsSize() const = 0;

	bool shouldSuspendScrollAnimations() const { return true; }

	IntPoint clampScrollPosition(const IntPoint&) const;

	// Let subclasses provide a way of asking for and servicing scroll
	// animations.
	bool scheduleAnimation();
	void serviceScrollAnimations(double monotonicTime);

	// Returns true if the GraphicsLayer tree needs to be rebuilt.
	virtual bool updateAfterCompositingChange() = 0;

	virtual bool userInputScrollable(ScrollbarOrientation) const = 0;
	virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0;

	int scrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? scrollPosition().x() : scrollPosition().y(); }
	int minimumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? minimumScrollPosition().x() : minimumScrollPosition().y(); }
	int maximumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? maximumScrollPosition().x() : maximumScrollPosition().y(); }
	int clampScrollPosition(ScrollbarOrientation orientation, int pos) { return std::max(std::min(pos, maximumScrollPosition(orientation)), minimumScrollPosition(orientation)); }

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

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

	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;

	int lineStep(ScrollbarOrientation) const;
	int documentStep(ScrollbarOrientation) const;
	virtual int pageStep(ScrollbarOrientation) const = 0;
	float pixelStep(ScrollbarOrientation) const;

	struct ScrollableAreaAnimators {
	OwnPtr<ScrollAnimator> scrollAnimator;
	};

	mutable OwnPtr<ScrollableAreaAnimators> m_animators;
	unsigned m_constrainsScrollingToContentEdge : 1;

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

	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 blink

	#endif // SKY_ENGINE_PLATFORM_SCROLL_SCROLLABLEAREA_H_