Output subsequence for children layers

third_party/WebKit/Source/core/paint/DeprecatedPaintLayerPainter.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 "config.h"
 #include "core/paint/DeprecatedPaintLayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/layout/ClipPathOperation.h"
 #include "core/layout/LayoutBlock.h"
@@ skipping 202 matching lines @@
     bool shouldPaintOutline = isSelfPaintingLayer && !isPaintingOverlayScrollbars
         && ((isPaintingScrollingContent && isPaintingCompositedBackground)
         || (!isPaintingScrollingContent && isPaintingCompositedForeground));
     bool shouldPaintContent = m_paintLayer.hasVisibleContent() && isSelfPaintingLayer && !isPaintingOverlayScrollbars;
 
     PaintResult result = FullyPainted;
 
     if (paintFlags & PaintLayerPaintingRootBackgroundOnly && !m_paintLayer.layoutObject()->isLayoutView() && !m_paintLayer.layoutObject()->isDocumentElement())
         return result;
 
-    Optional<SubsequenceRecorder> subsequenceRecorder;
-
-    bool scrollOffsetAccumulationChanged = paintingInfoArg.scrollOffsetAccumulation != m_paintLayer.previousScrollOffsetAccumulationForPainting();
-    if (scrollOffsetAccumulationChanged)
-        m_paintLayer.setPreviousScrollOffsetAccumulationForPainting(paintingInfoArg.scrollOffsetAccumulation);
-
-    if (!isPaintingOverlayScrollbars
-        && !paintingInfoArg.disableSubsequenceCache
-        && !(paintingInfoArg.globalPaintFlags() & GlobalPaintFlattenCompositingLayers)
-        && !(paintFlags & PaintLayerPaintingReflection)
-        && !(paintFlags & PaintLayerPaintingRootBackgroundOnly)) {
-        if (!scrollOffsetAccumulationChanged && !m_paintLayer.needsRepaint() && SubsequenceRecorder::useCachedSubsequenceIfPossible(*context, m_paintLayer))
-            return result;
-        subsequenceRecorder.emplace(*context, m_paintLayer);
-    }
-
     DeprecatedPaintLayerPaintingInfo paintingInfo = paintingInfoArg;
 
     if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()
         && (m_paintLayer.layoutObject()->hasOverflowClip() || m_paintLayer.layoutObject()->hasClip()))
         paintingInfo.disableSubsequenceCache = true;

[pdr., 2015/09/30 23:11:56]

Does this need to be moved too?

[Xianzhu, 2015/09/30 23:29:47]

Yes. This should control child subsequences. If not moved, it will also disable
caching of subsequences of this layer.

Done.

 
     // Ensure our lists are up-to-date.
     m_paintLayer.stackingNode()->updateLayerListsIfNeeded();
 
     LayoutPoint offsetFromRoot;
     m_paintLayer.convertToLayerCoords(paintingInfo.rootLayer, offsetFromRoot);
 
     if (m_paintLayer.compositingState() == PaintsIntoOwnBacking)
         offsetFromRoot.move(m_paintLayer.subpixelAccumulation());
     else
@@ skipping 95 matching lines @@
     bool shouldPaintMask = (paintFlags & PaintLayerPaintingCompositingMaskPhase) && shouldPaintContent && m_paintLayer.layoutObject()->hasMask() && !selectionOnly;
     bool shouldPaintClippingMask = (paintFlags & PaintLayerPaintingChildClippingMaskPhase) && shouldPaintContent && !selectionOnly;
 
     if (shouldPaintMask)
         paintMaskForFragments(layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags);
     if (shouldPaintClippingMask) {
         // Paint the border radius mask for the fragments.
         paintChildClippingMaskForFragments(layerFragments, context, localPaintingInfo, paintingRootForLayoutObject, paintFlags);
     }
 
-    // Set subsequence not cacheable if the bounding box of this layer and descendants is not fully contained
-    // by paintRect, because later paintRect changes may expose new contents which will need repainting.
-    if (result == MaybeNotFullyPainted && subsequenceRecorder)
-        subsequenceRecorder->setUncacheable();
+    m_paintLayer.setPreviousScrollOffsetAccumulationForPainting(paintingInfoArg.scrollOffsetAccumulation);
 
     return result;
 }
 
 bool DeprecatedPaintLayerPainter::needsToClip(const DeprecatedPaintLayerPaintingInfo& localPaintingInfo, const ClipRect& clipRect)
 {
     return clipRect.rect() != localPaintingInfo.paintDirtyRect || clipRect.hasRadius();
 }
 
 bool DeprecatedPaintLayerPainter::atLeastOneFragmentIntersectsDamageRect(DeprecatedPaintLayerFragments& fragments, const DeprecatedPaintLayerPaintingInfo& localPaintingInfo, PaintLayerFlags localPaintFlags, const LayoutPoint& offsetFromRoot)
@@ skipping 112 matching lines @@
 DeprecatedPaintLayerPainter::PaintResult DeprecatedPaintLayerPainter::paintChildren(unsigned childrenToVisit, GraphicsContext* context, const DeprecatedPaintLayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
 {
     PaintResult result = FullyPainted;
     if (!m_paintLayer.hasSelfPaintingLayerDescendant())
         return result;
 
 #if ENABLE(ASSERT)
     LayerListMutationDetector mutationChecker(m_paintLayer.stackingNode());
 #endif
 
-    IntSize scrollOffsetAccumulation = paintingInfo.scrollOffsetAccumulation;
+    DeprecatedPaintLayerStackingNodeIterator iterator(*m_paintLayer.stackingNode(), childrenToVisit);
+    DeprecatedPaintLayerStackingNode* child = iterator.next();
+    if (!child)
+        return result;
+
+    DisplayItem::Type subsequenceType;
+    if (childrenToVisit == NegativeZOrderChildren) {
+        subsequenceType = DisplayItem::SubsequenceNegativeZOrder;
+    } else {
+        ASSERT(childrenToVisit == (NormalFlowChildren | PositiveZOrderChildren));
+        subsequenceType = DisplayItem::SubsequenceNormalFlowAndPositiveZOrder;
+    }
+
+    Optional<SubsequenceRecorder> subsequenceRecorder;
+    if (!paintingInfo.disableSubsequenceCache
+        && !(paintingInfo.globalPaintFlags() & GlobalPaintFlattenCompositingLayers)
+        && !(paintFlags & PaintLayerPaintingReflection)
+        && !(paintFlags & PaintLayerPaintingRootBackgroundOnly)) {
+        if (!m_paintLayer.needsRepaint()
+            && paintingInfo.scrollOffsetAccumulation == m_paintLayer.previousScrollOffsetAccumulationForPainting()
+            && SubsequenceRecorder::useCachedSubsequenceIfPossible(*context, m_paintLayer, subsequenceType))
+            return result;
+        subsequenceRecorder.emplace(*context, m_paintLayer, subsequenceType);
+    }
+
+    IntSize scrollOffsetAccumulationForChildren = paintingInfo.scrollOffsetAccumulation;
     if (m_paintLayer.layoutObject()->hasOverflowClip())
-        scrollOffsetAccumulation += m_paintLayer.layoutBox()->scrolledContentOffset();
+        scrollOffsetAccumulationForChildren += m_paintLayer.layoutBox()->scrolledContentOffset();
 
-    DeprecatedPaintLayerStackingNodeIterator iterator(*m_paintLayer.stackingNode(), childrenToVisit);
-    while (DeprecatedPaintLayerStackingNode* child = iterator.next()) {
+    for (; child; child = iterator.next()) {
         DeprecatedPaintLayerPainter childPainter(*child->layer());
         // If this Layer should paint into its own backing or a grouped backing, that will be done via CompositedDeprecatedPaintLayerMapping::paintContents()
         // and CompositedDeprecatedPaintLayerMapping::doPaintTask().
-        if (!childPainter.shouldPaintLayerInSoftwareMode(paintingInfo.globalPaintFlags(), paintFlags))
+        if (!childPainter.shouldPaintLayerInSoftwareMode(paintingInfo.globalPaintFlags(), paintFlags)) {

[pdr., 2015/09/30 23:11:56]

Nit: extra curly braces.

[Xianzhu, 2015/09/30 23:29:47]

Done.

             continue;
+        }
 
         DeprecatedPaintLayerPaintingInfo childPaintingInfo = paintingInfo;
-        childPaintingInfo.scrollOffsetAccumulation = scrollOffsetAccumulation;
+        childPaintingInfo.scrollOffsetAccumulation = scrollOffsetAccumulationForChildren;
         // Rare case: accumulate scroll offset of non-stacking-context ancestors up to m_paintLayer.
         for (DeprecatedPaintLayer* parentLayer = child->layer()->parent(); parentLayer != &m_paintLayer; parentLayer = parentLayer->parent()) {
             if (parentLayer->layoutObject()->hasOverflowClip())
                 childPaintingInfo.scrollOffsetAccumulation += parentLayer->layoutBox()->scrolledContentOffset();
         }
 
         if (childPainter.paintLayer(context, childPaintingInfo, paintFlags) == MaybeNotFullyPainted)
             result = MaybeNotFullyPainted;
     }
+
+    // Set subsequence not cacheable if the bounding box of this layer and descendants is not fully contained
+    // by paintRect, because later paintRect changes may expose new contents which will need repainting.
+    if (result == MaybeNotFullyPainted && subsequenceRecorder)
+        subsequenceRecorder->setUncacheable();
+
     return result;
 }
 
 // FIXME: inline this.
 static bool paintForFixedRootBackground(const DeprecatedPaintLayer* layer, PaintLayerFlags paintFlags)
 {
     return layer->layoutObject()->isDocumentElement() && (paintFlags & PaintLayerPaintingRootBackgroundOnly);
 }
 
 bool DeprecatedPaintLayerPainter::shouldPaintLayerInSoftwareMode(const GlobalPaintFlags globalPaintFlags, PaintLayerFlags paintFlags)
@@ skipping 155 matching lines @@
     if (!m_paintLayer.containsDirtyOverlayScrollbars())
         return;
 
     DeprecatedPaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), paintFlags, LayoutSize(), paintingRoot);
     paintLayer(context, paintingInfo, PaintLayerPaintingOverlayScrollbars);
 
     m_paintLayer.setContainsDirtyOverlayScrollbars(false);
 }
 
 } // namespace blink