Improvement handling of background and outline paint phases

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

 // Copyright 2014 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/ObjectPainter.h"
 
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/LayoutTheme.h"
@@ skipping 170 matching lines @@
     }
 
     if (useTransparencyLayer)
         graphicsContext.endLayer();
 }
 
 } // namespace
 
 void ObjectPainter::paintOutline(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
-    ASSERT(paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseSelfOutline);
+    ASSERT(shouldPaintSelfOutline(paintInfo.phase));
 
     const ComputedStyle& styleToUse = m_layoutObject.styleRef();
     if (!styleToUse.hasOutline() || styleToUse.visibility() != VISIBLE)
         return;
 
     // Only paint the focus ring by hand if the theme isn't able to draw the focus ring.
     if (styleToUse.outlineStyleIsAuto() && !LayoutTheme::theme().shouldDrawDefaultFocusRing(m_layoutObject))
         return;
 
     Vector<LayoutRect> outlineRects;
@@ skipping 32 matching lines @@
 
     if (unitedOutlineRect == pixelSnappedOutlineRects[0]) {
         paintSingleRectangleOutline(paintInfo, unitedOutlineRect, styleToUse, color);
         return;
     }
     paintComplexOutline(paintInfo.context, pixelSnappedOutlineRects, styleToUse, color);
 }
 
 void ObjectPainter::paintInlineChildrenOutlines(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
-    ASSERT(paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseDescendantOutlines);
+    ASSERT(shouldPaintDescendantOutlines(paintInfo.phase));
 
-    PaintInfo childPaintInfo(paintInfo);
-    childPaintInfo.phase = paintInfo.phase == PaintPhaseDescendantOutlines ? PaintPhaseOutline : paintInfo.phase;
-
+    PaintInfo paintInfoForDescendants = paintInfo.forDescendants();
     for (LayoutObject* child = m_layoutObject.slowFirstChild(); child; child = child->nextSibling()) {
         if (child->isLayoutInline() && !toLayoutInline(child)->hasSelfPaintingLayer())
-            child->paint(childPaintInfo, paintOffset);
+            child->paint(paintInfoForDescendants, paintOffset);
     }
 }
 
 void ObjectPainter::addPDFURLRectIfNeeded(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     ASSERT(paintInfo.isPrinting());
     if (m_layoutObject.isElementContinuation() || !m_layoutObject.node() || !m_layoutObject.node()->isLink() || m_layoutObject.styleRef().visibility() != VISIBLE)
         return;
 
     KURL url = toElement(m_layoutObject.node())->hrefURL();
@@ skipping 267 matching lines @@
         quad[2] = FloatPoint(x2, y2 - std::max(-adjacentWidth2, 0));
         quad[3] = FloatPoint(x2, y1 + std::max(-adjacentWidth1, 0));
         break;
     }
 
     graphicsContext.fillPolygon(4, quad, color, antialias);
 }
 
 void ObjectPainter::paintAsPseudoStackingContext(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
-    bool preservePhase = paintInfo.phase == PaintPhaseSelection || paintInfo.phase == PaintPhaseTextClip;
-    if (!preservePhase && paintInfo.phase != PaintPhaseForeground)
+    if (paintInfo.phase == PaintPhaseSelection || paintInfo.phase == PaintPhaseTextClip) {

[pdr., 2016/01/14 19:51:50]

Can you add a comment here about why we preserve the phase for selection and
text clip?

[Xianzhu, 2016/01/15 01:05:33]

Done.

+        m_layoutObject.paint(paintInfo, paintOffset);
+        return;
+    }
+
+    if (paintInfo.phase != PaintPhaseForeground)
         return;
 
     PaintInfo info(paintInfo);
-    info.phase = preservePhase ? paintInfo.phase : PaintPhaseSelfBlockBackground;
+    info.phase = PaintPhaseBlockBackground;
     m_layoutObject.paint(info, paintOffset);
-    if (!preservePhase) {
-        info.phase = PaintPhaseDescendantBlockBackgrounds;
-        m_layoutObject.paint(info, paintOffset);
-        info.phase = PaintPhaseFloat;
-        m_layoutObject.paint(info, paintOffset);
-        info.phase = PaintPhaseForeground;
-        m_layoutObject.paint(info, paintOffset);
-        info.phase = PaintPhaseOutline;
-        m_layoutObject.paint(info, paintOffset);
-    }
+    info.phase = PaintPhaseFloat;
+    m_layoutObject.paint(info, paintOffset);
+    info.phase = PaintPhaseForeground;
+    m_layoutObject.paint(info, paintOffset);
+    info.phase = PaintPhaseOutline;
+    m_layoutObject.paint(info, paintOffset);
 }
 
 } // namespace blink