Implement CSSOM Smooth Scroll API

Source/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
@@ skipping 21 matching lines @@
 #include "wtf/Noncopyable.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class FloatPoint;
 class GraphicsContext;
 class GraphicsLayer;
 class PlatformGestureEvent;
 class PlatformWheelEvent;
+class ProgrammaticScrollAnimator;
 class ScrollAnimator;
 
 enum ScrollBehavior {
     ScrollBehaviorAuto,
     ScrollBehaviorInstant,
     ScrollBehaviorSmooth,
 };
 
 class PLATFORM_EXPORT ScrollableArea {
     WTF_MAKE_NONCOPYABLE(ScrollableArea);
 public:
     static int pixelsPerLineStep();
     static float minFractionToStepWhenPaging();
     static int maxOverlapBetweenPages();
 
     bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
     void scrollToOffsetWithoutAnimation(const FloatPoint&);
     void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);
 
+    void programmaticallyScrollSmoothlyToOffset(const FloatPoint&);
+
     // 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&);
 
     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; }
@@ skipping 28 matching lines @@
     bool hasOverlayScrollbars() const;
     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(); }
 
+    ProgrammaticScrollAnimator* programmaticScrollAnimator() const;
+    ProgrammaticScrollAnimator* existingProgrammaticScrollAnimator() const
+    {
+        return m_programmaticScrollAnimator.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 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 { }
@@ skipping 51 matching lines @@
 
     virtual bool scrollAnimatorEnabled() const { return false; }
 
     // NOTE: Only called from Internals for testing.
     void setScrollOffsetFromInternals(const IntPoint&);
 
     IntPoint clampScrollPosition(const IntPoint&) const;
 
     // Let subclasses provide a way of asking for and servicing scroll
     // animations.
+    virtual bool registerForAnimation() { return false; }
+    virtual void deregisterForAnimation() { }
     virtual bool scheduleAnimation() { return false; }
-    void serviceScrollAnimations();
+    virtual void serviceScrollAnimations(double monotonicTime);
+
 
     virtual bool usesCompositedScrolling() const { return false; }
     virtual void updateNeedsCompositedScrolling() { }
     virtual void updateHasVisibleNonLayerContent() { }
 
     virtual bool userInputScrollable(ScrollbarOrientation) const = 0;
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0;
 
+    // Notifications for compositor-driven animations.
+    void notifyAnimationStarted(double monotonicTime);
+    void notifyAnimationFinished(double monotonicTime);
+
+    void layerForScrollingDidChange();
+    void requiresMainThreadScrollingDidChange();
+    bool canUseCompositedScrollAnimations() const;
+
     // Convenience functions
     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)); }
 
     bool hasVerticalBarDamage() const { return m_hasVerticalBarDamage; }
     bool hasHorizontalBarDamage() const { return m_hasHorizontalBarDamage; }
 
     const IntRect& verticalBarDamage() const
@@ skipping 18 matching lines @@
     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;
 
     friend class ScrollingCoordinator;
+    friend class ProgrammaticScrollAnimator;
     virtual GraphicsLayer* layerForScrolling() const { return 0; }
     virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
     virtual GraphicsLayer* layerForVerticalScrollbar() const { return 0; }
     virtual GraphicsLayer* layerForScrollCorner() const { return 0; }
     bool hasLayerForHorizontalScrollbar() const;
     bool hasLayerForVerticalScrollbar() const;
     bool hasLayerForScrollCorner() const;
 
+    void cancelProgrammaticScrollAnimation();
+    virtual bool compositedScrollAnimationsEnabled() const { return false; }
+
     // For repaint after layout, stores the damage to be repainted for the
     // scrollbars.
     unsigned m_hasHorizontalBarDamage : 1;
     unsigned m_hasVerticalBarDamage : 1;
     IntRect m_horizontalBarDamage;
     IntRect m_verticalBarDamage;
 
 private:
     void scrollPositionChanged(const IntPoint&);
 
     // NOTE: Only called from the ScrollAnimator.
     friend class ScrollAnimator;
     void setScrollOffsetFromAnimation(const IntPoint&);
 
+    // Only called from ProgrammaticScrollAnimator.
+    void setScrollOffsetFromProgrammaticAnimation(const IntPoint&);
+
     // This function should be overriden by subclasses to perform the actual
     // scroll of the content.
     virtual void setScrollOffset(const IntPoint&) = 0;
 
     virtual int lineStep(ScrollbarOrientation) const;
     virtual int pageStep(ScrollbarOrientation) const = 0;
     virtual int documentStep(ScrollbarOrientation) const;
     virtual float pixelStep(ScrollbarOrientation) const;
 
     mutable OwnPtr<ScrollAnimator> m_scrollAnimator;
+    mutable OwnPtr<ProgrammaticScrollAnimator> m_programmaticScrollAnimator;
     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