Calculate paint invalidation rect for scrollbars

third_party/WebKit/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 129 matching lines @@
 
     // This is used to determine whether the incoming fractional scroll offset should
     // be truncated to integer. Current rule is that if preferCompositingToLCDTextEnabled()
     // is disabled (which is true on low-dpi device by default) we should do the truncation.
     // The justification is that non-composited elements using fractional scroll offsets
     // is causing too much nasty bugs but does not add too benefit on low-dpi devices.
     virtual bool shouldUseIntegerScrollOffset() const { return !RuntimeEnabledFeatures::fractionalScrollOffsetsEnabled(); }
 
     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;
-    virtual void invalidateScrollbar(Scrollbar*, const IntRect&);
+    void setScrollbarNeedsPaintInvalidation(Scrollbar*);
     virtual bool isScrollCornerVisible() const = 0;
     virtual IntRect scrollCornerRect() const = 0;
-    virtual void invalidateScrollCorner(const IntRect&);
+    void setScrollCornerNeedsPaintInvalidation();
     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
@@ skipping 64 matching lines @@
 
     virtual bool userInputScrollable(ScrollbarOrientation) const = 0;
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0;
 
     // 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_verticalBarDamage.isEmpty(); }
-    bool hasHorizontalBarDamage() const { return !m_horizontalBarDamage.isEmpty(); }
-    const IntRect& verticalBarDamage() const { return m_verticalBarDamage; }
-    const IntRect& horizontalBarDamage() const { return m_horizontalBarDamage; }
-
-    void addScrollbarDamage(Scrollbar* scrollbar, const IntRect& rect)
-    {
-        if (scrollbar == horizontalScrollbar())
-            m_horizontalBarDamage.unite(rect);
-        else
-            m_verticalBarDamage.unite(rect);
-    }
-
-    void resetScrollbarDamage()
-    {
-        m_verticalBarDamage = IntRect();
-        m_horizontalBarDamage = IntRect();
-    }
-
     virtual GraphicsLayer* layerForContainer() const;
     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 layerForScrollingDidChange(WebCompositorAnimationTimeline*);
 
     void cancelScrollAnimation();
     void cancelProgrammaticScrollAnimation();
 
     virtual ~ScrollableArea();
 
-    virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
-    virtual void invalidateScrollCornerRect(const IntRect&) = 0;
+    // Called when any of horizontal scrollbar, vertical scrollbar and scroll corner is setNeedsPaintInvalidation.
+    virtual void scrollControlWasSetNeedsPaintInvalidation() = 0;
 
     // Returns the default scroll style this area should scroll with when not
     // explicitly specified. E.g. The scrolling behavior of an element can be
     // specified in CSS.
     virtual ScrollBehavior scrollBehaviorStyle() const { return ScrollBehaviorInstant; }
 
     // TODO(bokan): This is only used in FrameView to check scrollability but is
     // needed here to allow RootFrameViewport to preserve wheelHandler
     // semantics. Not sure why it's FrameView specific, it could probably be
     // generalized to other types of ScrollableAreas.
@@ skipping 20 matching lines @@
     void setScrollOrigin(const IntPoint&);
     void resetScrollOriginChanged() { m_scrollOriginChanged = false; }
 
     // Needed to let the animators call scrollPositionChanged.
     friend class ScrollAnimatorBase;
     friend class ProgrammaticScrollAnimator;
     void scrollPositionChanged(const DoublePoint&, ScrollType);
 
     void clearScrollAnimators();
 
+    bool horizontalScrollbarNeedsPaintInvalidation() const { return m_horizontalScrollbarNeedsPaintInvalidation; }
+    bool verticalScrollbarNeedsPaintInvalidation() const { return m_verticalScrollbarNeedsPaintInvalidation; }
+    bool scrollCornerNeedsPaintInvalidation() const { return m_scrollCornerNeedsPaintInvalidation; }
+    void clearNeedsPaintInvalidationForScrollControls()
+    {
+        m_horizontalScrollbarNeedsPaintInvalidation = false;
+        m_verticalScrollbarNeedsPaintInvalidation = false;
+        m_scrollCornerNeedsPaintInvalidation = false;
+    }
+
 private:
     void programmaticScrollHelper(const DoublePoint&, ScrollBehavior);
     void userScrollHelper(const DoublePoint&, ScrollBehavior);
 
     // This function should be overriden by subclasses to perform the actual
     // scroll of the content. By default the DoublePoint version will just
     // call into the IntPoint version. If fractional scroll is needed, one
     // can override the DoublePoint version to take advantage of the double
     // precision scroll offset.
     // FIXME: Remove the IntPoint version. And change the function to
     // take DoubleSize. crbug.com/414283.
     virtual void setScrollOffset(const IntPoint&, ScrollType) = 0;
     virtual void setScrollOffset(const DoublePoint& offset, ScrollType scrollType)
     {
         setScrollOffset(flooredIntPoint(offset), scrollType);
     }
 
     virtual int lineStep(ScrollbarOrientation) const;
     virtual int pageStep(ScrollbarOrientation) const;
     virtual int documentStep(ScrollbarOrientation) const;
     virtual float pixelStep(ScrollbarOrientation) const;
 
-    // Stores the paint invalidations for the scrollbars during layout.
-    IntRect m_horizontalBarDamage;
-    IntRect m_verticalBarDamage;
-
     struct ScrollableAreaAnimators {
         OwnPtr<ScrollAnimatorBase> scrollAnimator;
         OwnPtr<ProgrammaticScrollAnimator> programmaticScrollAnimator;
     };
 
     mutable OwnPtr<ScrollableAreaAnimators> m_animators;
 
     unsigned m_inLiveResize : 1;
 
     unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle
 
     unsigned m_scrollOriginChanged : 1;
 
+    unsigned m_horizontalScrollbarNeedsPaintInvalidation : 1;
+    unsigned m_verticalScrollbarNeedsPaintInvalidation : 1;
+    unsigned m_scrollCornerNeedsPaintInvalidation : 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 // ScrollableArea_h