Consider subpixel accumulation when invalidating paint

Source/core/rendering/RenderObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1446 matching lines @@
 template<typename T> void addJsonObjectForRect(TracedValue& value, const char* name, const T& rect)
 {
     value.beginDictionary(name)
         .setDouble("x", rect.x())
         .setDouble("y", rect.y())
         .setDouble("width", rect.width())
         .setDouble("height", rect.height())
         .endDictionary();
 }
 
-static PassRefPtr<TraceEvent::ConvertableToTraceFormat> jsonObjectForPaintInvalidationInfo(const IntRect& rect, const String& invalidationReason)
+static PassRefPtr<TraceEvent::ConvertableToTraceFormat> jsonObjectForPaintInvalidationInfo(const LayoutRect& rect, const String& invalidationReason)
 {
     TracedValue value;
     addJsonObjectForRect(value, "rect", rect);
     value.setString("invalidation_reason", invalidationReason);
     return value.finish();
 }
 
 LayoutRect RenderObject::computePaintInvalidationRect(const RenderLayerModelObject* paintInvalidationContainer) const
 {
     return clippedOverflowRectForPaintInvalidation(paintInvalidationContainer);
 }
 
-void RenderObject::invalidatePaintUsingContainer(const RenderLayerModelObject* paintInvalidationContainer, const IntRect& r, InvalidationReason invalidationReason) const
+void RenderObject::invalidatePaintUsingContainer(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& r, InvalidationReason invalidationReason) const
 {
     if (r.isEmpty())
         return;
 
     // FIXME: This should be an assert, but editing/selection can trigger this case to invalidate
     // the selection. crbug.com/368140.
     if (!isRooted())
         return;
 
     TRACE_EVENT2(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "RenderObject::invalidatePaintUsingContainer()",
@@ skipping 32 matching lines @@
         return;
 
     if (view()->document().printing())
         return; // Don't invalidate paints if we're printing.
 
     // FIXME: really, we're in the paint invalidation phase here, and the following queries are legal.
     // Until those states are fully fledged, I'll just disable the ASSERTS.
     DisableCompositingQueryAsserts disabler;
     const RenderLayerModelObject* paintInvalidationContainer = containerForPaintInvalidation();
     LayoutRect paintInvalidationRect = boundsRectForPaintInvalidation(paintInvalidationContainer);
-    invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(paintInvalidationRect), InvalidationPaint);
+    invalidatePaintUsingContainer(paintInvalidationContainer, paintInvalidationRect, InvalidationPaint);
 }
 
 LayoutRect RenderObject::boundsRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer) const
 {
     if (!paintInvalidationContainer)
         return computePaintInvalidationRect(paintInvalidationContainer);
     return RenderLayer::computePaintInvalidationRect(this, paintInvalidationContainer->layer());
 }
 
 void RenderObject::invalidatePaintRectangle(const LayoutRect& r) const
 {
     if (!isRooted())
         return;
 
     if (view()->document().printing())
         return; // Don't invalidate paints if we're printing.
 
     LayoutRect dirtyRect(r);
 
     const RenderLayerModelObject* paintInvalidationContainer = containerForPaintInvalidation();
     RenderLayer::mapRectToPaintInvalidationBacking(this, paintInvalidationContainer, dirtyRect);
-    invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(dirtyRect), InvalidationPaintRectangle);
+    invalidatePaintUsingContainer(paintInvalidationContainer, dirtyRect, InvalidationPaintRectangle);
 }
 
 IntRect RenderObject::pixelSnappedAbsoluteClippedOverflowRect() const
 {
     return pixelSnappedIntRect(absoluteClippedOverflowRect());
 }
 
 const char* RenderObject::invalidationReasonToString(InvalidationReason reason) const
 {
     switch (reason) {
@@ skipping 123 matching lines @@
 }
 
 void RenderObject::incrementallyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds)
 {
     ASSERT(paintInvalidationContainer);
 
     ASSERT(oldBounds.location() == newBounds.location());
 
     LayoutUnit deltaRight = newBounds.maxX() - oldBounds.maxX();
     if (deltaRight > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), InvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), InvalidationIncremental);
     else if (deltaRight < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), InvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), InvalidationIncremental);
 
     LayoutUnit deltaBottom = newBounds.maxY() - oldBounds.maxY();
     if (deltaBottom > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), InvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), InvalidationIncremental);
     else if (deltaBottom < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), InvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), InvalidationIncremental);
 }
 
 void RenderObject::fullyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, InvalidationReason invalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds)
 {
     // Otherwise do full paint invalidation.
-    invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds), invalidationReason);
+    invalidatePaintUsingContainer(paintInvalidationContainer, oldBounds, invalidationReason);
     if (newBounds != oldBounds)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds), invalidationReason);
+        invalidatePaintUsingContainer(paintInvalidationContainer, newBounds, invalidationReason);
 }
 
 void RenderObject::invalidatePaintForOverflow()
 {
 }
 
 void RenderObject::invalidatePaintForOverflowIfNeeded()
 {
     if (shouldInvalidateOverflowForPaint())
         invalidatePaintForOverflow();
@@ skipping 1726 matching lines @@
 {
     if (object1) {
         const WebCore::RenderObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif