static bool shouldCreateSubsequence(const PaintLayer& paintLayer, GraphicsContext& context, const PaintLayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
{
// Caching is not needed during printing.
if (context.printing())
return false;
// Don't create subsequence for a composited layer because if it can be cached,
// we can skip the whole painting in GraphicsLayer::paint() with CachedDisplayItemList.
// This also avoids conflict of PaintLayer::previousXXX() when paintLayer is composited
// scrolling and is painted twice for GraphicsLayers of container and scrolling contents.
if (paintLayer.compositingState() == PaintsIntoOwnBacking)
return false;
// Don't create subsequence during special painting to avoid cache conflict with normal painting.
if (paintingInfo.globalPaintFlags() & GlobalPaintFlattenCompositingLayers)
return false;
if (paintFlags & (PaintLayerPaintingReflection | PaintLayerPaintingRootBackgroundOnly | PaintLayerPaintingOverlayScrollbars | PaintLayerUncachedClipRects))
return false;
// Create subsequence for only stacking contexts whose painting are atomic.
if (!paintLayer.stackingNode()->isStackingContext())
return false;
// The layer doesn't have children. Subsequence caching is not worth because normally the actual painting will be cheap.
if (!PaintLayerStackingNodeIterator(*paintLayer.stackingNode(), AllChildren).next())
return false;
return true;
}
void GraphicsLayerTreeBuilder::rebuild(PaintLayer& layer, AncestorInfo info)
{
// Make the layer compositing if necessary, and set up clipping and content layers.
// Note that we can only do work here that is independent of whether the descendant layers
// have been processed. computeCompositingRequirements() will already have done the paint invalidation if necessary.
layer.stackingNode()->updateLayerListsIfNeeded();
const bool hasCompositedLayerMapping = layer.hasCompositedLayerMapping();
CompositedLayerMapping* currentCompositedLayerMapping = layer.compositedLayerMapping();
// If this layer has a compositedLayerMapping, then that is where we place subsequent children GraphicsLayers.
// Otherwise children continue to append to the child list of the enclosing layer.
GraphicsLayerVector layerChildren;
AncestorInfo infoForChildren(info);
if (hasCompositedLayerMapping) {
infoForChildren.childLayersOfEnclosingCompositedLayer = &layerChildren;
infoForChildren.enclosingCompositedLayer = &layer;
}
#if ENABLE(ASSERT)
LayerListMutationDetector mutationChecker(layer.stackingNode());
#endif
if (layer.stackingNode()->isStackingContext()) {
PaintLayerStackingNodeIterator iterator(*layer.stackingNode(), NegativeZOrderChildren);
while (PaintLayerStackingNode* curNode = iterator.next())
rebuild(*curNode->layer(), infoForChildren);
// If a negative z-order child is compositing, we get a foreground layer which needs to get parented.
if (hasCompositedLayerMapping && currentCompositedLayerMapping->foregroundLayer())
infoForChildren.childLayersOfEnclosingCompositedLayer->append(currentCompositedLayerMapping->foregroundLayer());
}
PaintLayerStackingNodeIterator iterator(*layer.stackingNode(), NormalFlowChildren | PositiveZOrderChildren);
while (PaintLayerStackingNode* curNode = iterator.next())
rebuild(*curNode->layer(), infoForChildren);
if (hasCompositedLayerMapping) {
bool parented = false;
if (layer.layoutObject()->isLayoutPart())
parented = PaintLayerCompositor::attachFrameContentLayersToIframeLayer(toLayoutPart(layer.layoutObject()));
if (!parented)
currentCompositedLayerMapping->setSublayers(layerChildren);
if (shouldAppendLayer(layer))
info.childLayersOfEnclosingCompositedLayer->append(currentCompositedLayerMapping->childForSuperlayers());
}
if (layer.scrollParent()
&& layer.scrollParent()->hasCompositedLayerMapping()
&& layer.scrollParent()->compositedLayerMapping()->needsToReparentOverflowControls()
&& layer.scrollParent()->getScrollableArea()->topmostScrollChild() == &layer)
info.childLayersOfEnclosingCompositedLayer->append(layer.scrollParent()->compositedLayerMapping()->detachLayerForOverflowControls(*info.enclosingCompositedLayer));
}
static void checkIsClippingStackingContextAndContainer(LayoutBoxModelObject& obj)
{
EXPECT_TRUE(obj.canContainFixedPositionObjects());
EXPECT_TRUE(obj.hasClipRelatedProperty());
EXPECT_TRUE(obj.style()->containsPaint());
// TODO(leviw): Ideally, we wouldn't require a paint layer to handle the clipping
// and stacking performed by paint containment.
ASSERT(obj.layer());
PaintLayer* layer = obj.layer();
EXPECT_TRUE(layer->stackingNode() && layer->stackingNode()->isStackingContext());
}
void PaintLayerStackingNode::rebuildZOrderLists() {
#if DCHECK_IS_ON()
DCHECK(m_layerListMutationAllowed);
#endif
DCHECK(isDirtyStackingContext());
for (PaintLayer* child = layer()->firstChild(); child;
child = child->nextSibling())
child->stackingNode()->collectLayers(m_posZOrderList, m_negZOrderList);
// Sort the two lists.
if (m_posZOrderList)
std::stable_sort(m_posZOrderList->begin(), m_posZOrderList->end(),
compareZIndex);
if (m_negZOrderList)
std::stable_sort(m_negZOrderList->begin(), m_negZOrderList->end(),
compareZIndex);
// Append layers for top layer elements after normal layer collection, to
// ensure they are on top regardless of z-indexes. The layoutObjects of top
// layer elements are children of the view, sorted in top layer stacking
// order.
if (layer()->isRootLayer()) {
LayoutBlockFlow* rootBlock = layoutObject()->view();
// If the viewport is paginated, everything (including "top-layer" elements)
// gets redirected to the flow thread. So that's where we have to look, in
// that case.
if (LayoutBlockFlow* multiColumnFlowThread =
rootBlock->multiColumnFlowThread())
rootBlock = multiColumnFlowThread;
for (LayoutObject* child = rootBlock->firstChild(); child;
child = child->nextSibling()) {
Element* childElement = (child->node() && child->node()->isElementNode())
? toElement(child->node())
: 0;
if (childElement && childElement->isInTopLayer()) {
PaintLayer* layer = toLayoutBoxModelObject(child)->layer();
// Create the buffer if it doesn't exist yet.
if (!m_posZOrderList)
m_posZOrderList = wrapUnique(new Vector<PaintLayerStackingNode*>);
m_posZOrderList->append(layer->stackingNode());
}
}
}
#if ENABLE(ASSERT)
updateStackingParentForZOrderLists(this);
#endif
m_zOrderListsDirty = false;
}
PaintLayerStackingNode* PaintLayerStackingNodeReverseIterator::next()
{
if (m_remainingChildren & NegativeZOrderChildren) {
Vector<PaintLayerStackingNode*>* negZOrderList = m_root.negZOrderList();
if (negZOrderList && m_index >= 0)
return negZOrderList->at(m_index--);
m_remainingChildren &= ~NegativeZOrderChildren;
setIndexToLastItem();
}
if (m_remainingChildren & NormalFlowChildren) {
for (; m_currentNormalFlowChild; m_currentNormalFlowChild = m_currentNormalFlowChild->previousSibling()) {
if (!m_currentNormalFlowChild->stackingNode()->isStacked() && !m_currentNormalFlowChild->isReflection()) {
PaintLayer* normalFlowChild = m_currentNormalFlowChild;
m_currentNormalFlowChild = m_currentNormalFlowChild->previousSibling();
return normalFlowChild->stackingNode();
}
}
m_remainingChildren &= ~NormalFlowChildren;
setIndexToLastItem();
}
if (m_remainingChildren & PositiveZOrderChildren) {
Vector<PaintLayerStackingNode*>* posZOrderList = m_root.posZOrderList();
if (posZOrderList && m_index >= 0)
return posZOrderList->at(m_index--);
m_remainingChildren &= ~PositiveZOrderChildren;
setIndexToLastItem();
}
return 0;
}
PaintLayerStackingNode* PaintLayerStackingNode::ancestorStackingContextNode()
const {
for (PaintLayer* ancestor = layer()->parent(); ancestor;
ancestor = ancestor->parent()) {
PaintLayerStackingNode* stackingNode = ancestor->stackingNode();
if (stackingNode->isStackingContext())
return stackingNode;
}
return 0;
}
void PaintLayerStackingNode::collectLayers(
std::unique_ptr<Vector<PaintLayerStackingNode*>>& posBuffer,
std::unique_ptr<Vector<PaintLayerStackingNode*>>& negBuffer) {
if (layer()->isInTopLayer())
return;
if (isStacked()) {
std::unique_ptr<Vector<PaintLayerStackingNode*>>& buffer =
(zIndex() >= 0) ? posBuffer : negBuffer;
if (!buffer)
buffer = wrapUnique(new Vector<PaintLayerStackingNode*>);
buffer->append(this);
}
if (!isStackingContext()) {
for (PaintLayer* child = layer()->firstChild(); child;
child = child->nextSibling())
child->stackingNode()->collectLayers(posBuffer, negBuffer);
}
}
PaintLayerStackingNode* PaintLayerStackingNodeIterator::next()
{
if (m_remainingChildren & NegativeZOrderChildren) {
Vector<PaintLayerStackingNode*>* negZOrderList = m_root.negZOrderList();
if (negZOrderList && m_index < negZOrderList->size())
return negZOrderList->at(m_index++);
m_index = 0;
m_remainingChildren &= ~NegativeZOrderChildren;
}
if (m_remainingChildren & NormalFlowChildren) {
for (; m_currentNormalFlowChild; m_currentNormalFlowChild = m_currentNormalFlowChild->nextSibling()) {
if (!m_currentNormalFlowChild->stackingNode()->isStacked() && !m_currentNormalFlowChild->isReflection()) {
PaintLayer* normalFlowChild = m_currentNormalFlowChild;
m_currentNormalFlowChild = m_currentNormalFlowChild->nextSibling();
return normalFlowChild->stackingNode();
}
}
// We reset the iterator in case we reuse it.
m_currentNormalFlowChild = m_root.layer()->firstChild();
m_remainingChildren &= ~NormalFlowChildren;
}
if (m_remainingChildren & PositiveZOrderChildren) {
Vector<PaintLayerStackingNode*>* posZOrderList = m_root.posZOrderList();
if (posZOrderList && m_index < posZOrderList->size())
return posZOrderList->at(m_index++);
m_index = 0;
m_remainingChildren &= ~PositiveZOrderChildren;
}
return 0;
}