Calculate paint invalidation rect for scrollbars

third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 33 matching lines @@
 
 #include "platform/TraceEvent.h"
 
 static const int kPixelsPerLineStep = 40;
 static const float kMinFractionToStepWhenPaging = 0.875f;
 
 namespace blink {
 
 struct SameSizeAsScrollableArea {
     virtual ~SameSizeAsScrollableArea();
-    IntRect scrollbarDamage[2];
 #if ENABLE(ASSERT) && ENABLE(OILPAN)
     VerifyEagerFinalization verifyEager;
 #endif
     void* pointer;
     unsigned bitfields : 16;
     IntPoint origin;
 };
 
 static_assert(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea), "ScrollableArea should stay small");
 
@@ skipping 10 matching lines @@
 int ScrollableArea::maxOverlapBetweenPages()
 {
     static int maxOverlapBetweenPages = ScrollbarTheme::theme()->maxOverlapBetweenPages();
     return maxOverlapBetweenPages;
 }
 
 ScrollableArea::ScrollableArea()
     : m_inLiveResize(false)
     , m_scrollbarOverlayStyle(ScrollbarOverlayStyleDefault)
     , m_scrollOriginChanged(false)
+    , m_horizontalScrollbarNeedsPaintInvalidation(false)
+    , m_verticalScrollbarNeedsPaintInvalidation(false)
+    , m_scrollCornerNeedsPaintInvalidation(false)
 {
 }
 
 ScrollableArea::~ScrollableArea()
 {
 }
 
 void ScrollableArea::clearScrollAnimators()
 {
     m_animators.clear();
@@ skipping 144 matching lines @@
     DoublePoint truncatedPosition = shouldUseIntegerScrollOffset() ? flooredIntPoint(position) : position;
 
     // Tell the derived class to scroll its contents.
     setScrollOffset(truncatedPosition, scrollType);
 
     Scrollbar* verticalScrollbar = this->verticalScrollbar();
 
     // Tell the scrollbars to update their thumb postions.
     if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar()) {
         horizontalScrollbar->offsetDidChange();
-        if (horizontalScrollbar->isOverlayScrollbar() && !hasLayerForHorizontalScrollbar()) {
-            if (!verticalScrollbar)
-                horizontalScrollbar->invalidate();
-            else {
-                // If there is both a horizontalScrollbar and a verticalScrollbar,
-                // then we must also invalidate the corner between them.
-                IntRect boundsAndCorner = horizontalScrollbar->boundsRect();
-                boundsAndCorner.setWidth(boundsAndCorner.width() + verticalScrollbar->width());
-                horizontalScrollbar->invalidateRect(boundsAndCorner);
-            }
-        }
+        if (horizontalScrollbar->isOverlayScrollbar() && !hasLayerForHorizontalScrollbar())
+            setScrollbarNeedsPaintInvalidation(horizontalScrollbar);
     }
     if (verticalScrollbar) {
         verticalScrollbar->offsetDidChange();
         if (verticalScrollbar->isOverlayScrollbar() && !hasLayerForVerticalScrollbar())
-            verticalScrollbar->invalidate();
+            setScrollbarNeedsPaintInvalidation(verticalScrollbar);
     }
 
     if (scrollPositionDouble() != oldPosition) {
         // FIXME: Pass in DoubleSize. crbug.com/414283.
         scrollAnimator()->notifyContentAreaScrolled(toFloatSize(scrollPositionDouble() - oldPosition));
     }
 
     scrollAnimator()->setCurrentPosition(toFloatPoint(position));
 }
 
@@ skipping 120 matching lines @@
     Scrollbar* hScrollbar = horizontalScrollbar();
     return hScrollbar && hScrollbar->isOverlayScrollbar();
 }
 
 void ScrollableArea::setScrollbarOverlayStyle(ScrollbarOverlayStyle overlayStyle)
 {
     m_scrollbarOverlayStyle = overlayStyle;
 
     if (Scrollbar* scrollbar = horizontalScrollbar()) {
         ScrollbarTheme::theme()->updateScrollbarOverlayStyle(scrollbar);
-        scrollbar->invalidate();
+        setScrollbarNeedsPaintInvalidation(scrollbar);
     }
 
     if (Scrollbar* scrollbar = verticalScrollbar()) {
         ScrollbarTheme::theme()->updateScrollbarOverlayStyle(scrollbar);
-        scrollbar->invalidate();
+        setScrollbarNeedsPaintInvalidation(scrollbar);
     }
 }
 
-void ScrollableArea::invalidateScrollbar(Scrollbar* scrollbar, const IntRect& rect)
+void ScrollableArea::setScrollbarNeedsPaintInvalidation(Scrollbar* scrollbar)
 {
     if (scrollbar == horizontalScrollbar()) {
         if (GraphicsLayer* graphicsLayer = layerForHorizontalScrollbar()) {
             graphicsLayer->setNeedsDisplay();
             graphicsLayer->setContentsNeedsDisplay();
             return;
         }
-        invalidateScrollbarRect(scrollbar, rect);
+        m_horizontalScrollbarNeedsPaintInvalidation = true;
+        scrollControlWasSetNeedsPaintInvalidation();
         return;
     }
     if (scrollbar == verticalScrollbar()) {
         if (GraphicsLayer* graphicsLayer = layerForVerticalScrollbar()) {
             graphicsLayer->setNeedsDisplay();
             graphicsLayer->setContentsNeedsDisplay();
             return;
         }
-        invalidateScrollbarRect(scrollbar, rect);
+        m_verticalScrollbarNeedsPaintInvalidation = true;
+        scrollControlWasSetNeedsPaintInvalidation();
         return;
     }
     // Otherwise the scrollbar is just created and has not been set as either
     // horizontalScrollbar() or verticalScrollbar().
 }
 
-void ScrollableArea::invalidateScrollCorner(const IntRect& rect)
+void ScrollableArea::setScrollCornerNeedsPaintInvalidation()
 {
     if (GraphicsLayer* graphicsLayer = layerForScrollCorner()) {
         graphicsLayer->setNeedsDisplay();
         return;
     }
-    invalidateScrollCornerRect(rect);
+    m_scrollCornerNeedsPaintInvalidation = true;
+    scrollControlWasSetNeedsPaintInvalidation();
 }
 
 bool ScrollableArea::hasLayerForHorizontalScrollbar() const
 {
     return layerForHorizontalScrollbar();
 }
 
 bool ScrollableArea::hasLayerForVerticalScrollbar() const
 {
     return layerForVerticalScrollbar();
@@ skipping 127 matching lines @@
         verticalScrollbarWidth = !verticalBar->isOverlayScrollbar() ? verticalBar->width() : 0;
     if (Scrollbar* horizontalBar = horizontalScrollbar())
         horizontalScrollbarHeight = !horizontalBar->isOverlayScrollbar() ? horizontalBar->height() : 0;
 
     return IntSize(std::max(0, size.width() - verticalScrollbarWidth),
         std::max(0, size.height() - horizontalScrollbarHeight));
 
 }
 
 } // namespace blink