Support subpixel layout for borders.

third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/BoxPaintInvalidator.h"
 
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/CompositedLayerMapping.h"
 #include "core/paint/ObjectPaintInvalidator.h"
@@ skipping 20 matching lines @@
 void BoxPaintInvalidator::boxWillBeDestroyed(const LayoutBox& box) {
   DCHECK(box.hasPreviousBoxGeometries() ==
          previousBoxGeometriesMap().contains(&box));
   if (box.hasPreviousBoxGeometries())
     previousBoxGeometriesMap().erase(&box);
 }
 
 static LayoutRect computeRightDelta(const LayoutPoint& location,
                                     const LayoutSize& oldSize,
                                     const LayoutSize& newSize,
-                                    int extraWidth) {
+                                    const LayoutUnit& extraWidth) {
   LayoutUnit delta = newSize.width() - oldSize.width();
   if (delta > 0) {
     return LayoutRect(location.x() + oldSize.width() - extraWidth, location.y(),
                       delta + extraWidth, newSize.height());
   }
   if (delta < 0) {
     return LayoutRect(location.x() + newSize.width() - extraWidth, location.y(),
                       -delta + extraWidth, oldSize.height());
   }
   return LayoutRect();
 }
 
 static LayoutRect computeBottomDelta(const LayoutPoint& location,
                                      const LayoutSize& oldSize,
                                      const LayoutSize& newSize,
-                                     int extraHeight) {
+                                     const LayoutUnit& extraHeight) {
   LayoutUnit delta = newSize.height() - oldSize.height();
   if (delta > 0) {
     return LayoutRect(location.x(),
                       location.y() + oldSize.height() - extraHeight,
                       newSize.width(), delta + extraHeight);
   }
   if (delta < 0) {
     return LayoutRect(location.x(),
                       location.y() + newSize.height() - extraHeight,
                       oldSize.width(), -delta + extraHeight);
   }
   return LayoutRect();
 }
 
 bool BoxPaintInvalidator::incrementallyInvalidatePaint(
     PaintInvalidationReason reason,
     const LayoutRect& oldRect,
     const LayoutRect& newRect) {
   DCHECK(oldRect.location() == newRect.location());
   LayoutRect rightDelta = computeRightDelta(
       newRect.location(), oldRect.size(), newRect.size(),
-      reason == PaintInvalidationIncremental ? m_box.borderRight() : 0);
+      reason == PaintInvalidationIncremental ? m_box.borderRight()
+                                             : LayoutUnit());
   LayoutRect bottomDelta = computeBottomDelta(
       newRect.location(), oldRect.size(), newRect.size(),
-      reason == PaintInvalidationIncremental ? m_box.borderBottom() : 0);
+      reason == PaintInvalidationIncremental ? m_box.borderBottom()
+                                             : LayoutUnit());
 
   if (rightDelta.isEmpty() && bottomDelta.isEmpty())
     return false;
 
   ObjectPaintInvalidator objectPaintInvalidator(m_box);
   objectPaintInvalidator.invalidatePaintUsingContainer(
       *m_context.paintInvalidationContainer, rightDelta, reason);
   objectPaintInvalidator.invalidatePaintUsingContainer(
       *m_context.paintInvalidationContainer, bottomDelta, reason);
   return true;
@@ skipping 286 matching lines @@
 
 LayoutRect BoxPaintInvalidator::previousLayoutOverflowRect() {
   DCHECK(m_box.hasPreviousBoxGeometries() ==
          previousBoxGeometriesMap().contains(&m_box));
   return m_box.hasPreviousBoxGeometries()
              ? previousBoxGeometriesMap().get(&m_box).layoutOverflowRect
              : LayoutRect();
 }
 
 }  // namespace blink