Implement the algorithm to test merging and overlap in PaintArtifactCompositor.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp

 // Copyright 2015 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 "platform/graphics/compositing/PaintArtifactCompositor.h"
 
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/picture_layer.h"
 #include "cc/playback/display_item_list.h"
 #include "cc/playback/display_item_list_settings.h"
 #include "cc/playback/drawing_display_item.h"
 #include "cc/playback/transform_display_item.h"
 #include "cc/trees/clip_node.h"
 #include "cc/trees/effect_node.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/property_tree.h"
 #include "cc/trees/scroll_node.h"
 #include "cc/trees/transform_node.h"
+#include "core/paint/PaintPropertyTreePrinter.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "platform/graphics/paint/ForeignLayerDisplayItem.h"
+#include "platform/graphics/paint/GeometryMapper.h"
 #include "platform/graphics/paint/PaintArtifact.h"
+#include "platform/graphics/paint/PropertyTreeState.h"
 #include "platform/graphics/paint/RasterInvalidationTracking.h"
 #include "platform/graphics/paint/ScrollPaintPropertyNode.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebCompositorSupport.h"
 #include "public/platform/WebLayer.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
@@ skipping 26 matching lines @@
 }
 
 class PaintArtifactCompositor::ContentLayerClientImpl
     : public cc::ContentLayerClient {
   WTF_MAKE_NONCOPYABLE(ContentLayerClientImpl);
   USING_FAST_MALLOC(ContentLayerClientImpl);
 
  public:
   ContentLayerClientImpl(DisplayItem::Id paintChunkId)
       : m_id(paintChunkId),
-        m_debugName(paintChunkId.client.debugName()),
         m_ccPictureLayer(cc::PictureLayer::Create(this)) {}
 
   void SetDisplayList(scoped_refptr<cc::DisplayItemList> ccDisplayItemList) {
     m_ccDisplayItemList = std::move(ccDisplayItemList);
   }
   void SetPaintableRegion(gfx::Rect region) { m_paintableRegion = region; }
 
+  void addPaintChunkDebugData(std::unique_ptr<JSONArray> json) {
+    m_paintChunkDebugData.append(std::move(json));
+  }
+
+  void clearPaintChunkDebugData() { m_paintChunkDebugData.clear(); }
+
   // cc::ContentLayerClient
   gfx::Rect PaintableRegion() override { return m_paintableRegion; }
   scoped_refptr<cc::DisplayItemList> PaintContentsToDisplayList(
       PaintingControlSetting) override {
     return m_ccDisplayItemList;
   }
   bool FillsBoundsCompletely() const override { return false; }
   size_t GetApproximateUnsharedMemoryUsage() const override {
     // TODO(jbroman): Actually calculate memory usage.
     return 0;
@@ skipping 35 matching lines @@
       // TODO(crbug.com/496260): Some antialiasing effects overflow the paint
       // invalidation rect.
       IntRect r = rasterInvalidationInfo->rect;
       r.inflate(1);
       tracking.rasterInvalidationRegionSinceLastPaint.unite(r);
     }
   }
 
   std::unique_ptr<JSONObject> layerAsJSON() {
     std::unique_ptr<JSONObject> json = JSONObject::create();
-    json->setString("name", m_debugName);
     IntSize bounds(m_ccPictureLayer->bounds().width(),
                    m_ccPictureLayer->bounds().height());
     if (!bounds.isEmpty())
       json->setArray("bounds", sizeAsJSONArray(bounds));
     json->setBoolean("contentsOpaque", m_ccPictureLayer->contents_opaque());
     json->setBoolean("drawsContent", m_ccPictureLayer->DrawsContent());
 
+    std::unique_ptr<JSONArray> paintChunkContentsArray = JSONArray::create();
+    for (const auto& debugData : m_paintChunkDebugData) {
+      paintChunkContentsArray->pushValue(debugData->clone());
+    }
+    json->setArray("paintChunkContents", std::move(paintChunkContentsArray));
+
     ccLayersRasterInvalidationTrackingMap().asJSON(m_ccPictureLayer.get(),
                                                    json.get());
     return json;
   }
 
   scoped_refptr<cc::PictureLayer> ccPictureLayer() { return m_ccPictureLayer; }
 
   bool matches(const PaintChunk& paintChunk) {
     return paintChunk.id && m_id == *paintChunk.id;
   }
 
  private:
   PaintChunk::Id m_id;
-  String m_debugName;
   scoped_refptr<cc::PictureLayer> m_ccPictureLayer;
   scoped_refptr<cc::DisplayItemList> m_ccDisplayItemList;
   gfx::Rect m_paintableRegion;
+
+  Vector<std::unique_ptr<JSONArray>> m_paintChunkDebugData;
 };
 
 PaintArtifactCompositor::PaintArtifactCompositor() {
   if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled())
     return;
   m_rootLayer = cc::Layer::Create();
   m_webLayer = Platform::current()->compositorSupport()->createLayerFromCCLayer(
       m_rootLayer.get());
   m_isTrackingRasterInvalidations = false;
 }
@@ skipping 47 matching lines @@
     // to raster in a different space than that of the visual rects. We'll be
     // reworking visual rects further for SPv2, so for now we just pass a
     // visual rect large enough to make sure items raster.
     list->CreateAndAppendDrawingItem<cc::DrawingDisplayItem>(
         largeRect, sk_ref_sp(picture));
   }
 }
 
 static scoped_refptr<cc::DisplayItemList> recordPaintChunk(
     const PaintArtifact& artifact,
-    const PaintChunk& chunk,
+    const PendingLayer& pendingLayer,
     const gfx::Rect& combinedBounds) {
   cc::DisplayItemListSettings settings;
   scoped_refptr<cc::DisplayItemList> list =
       cc::DisplayItemList::Create(settings);
 
   gfx::Transform translation;
   translation.Translate(-combinedBounds.x(), -combinedBounds.y());
   // Passing combinedBounds as the visual rect for the begin/end transform item
   // would normally be the sensible thing to do, but see comment above re:
   // visual rects for drawing items and further rework in flight.
   list->CreateAndAppendPairedBeginItem<cc::TransformDisplayItem>(translation);
 
   const DisplayItemList& displayItems = artifact.getDisplayItemList();
-  for (const auto& displayItem : displayItems.itemsInPaintChunk(chunk))
-    appendDisplayItemToCcDisplayItemList(displayItem, list.get());
+  for (const auto& paintChunk : pendingLayer.paintChunks) {
+    for (const auto& displayItem : displayItems.itemsInPaintChunk(paintChunk))
+      appendDisplayItemToCcDisplayItemList(displayItem, list.get());
+  }
 
   list->CreateAndAppendPairedEndItem<cc::EndTransformDisplayItem>();
 
   list->Finalize();
   return list;
 }
 
 scoped_refptr<cc::Layer> foreignLayerForPaintChunk(
     const PaintArtifact& paintArtifact,
     const PaintChunk& paintChunk,
@@ skipping 36 matching lines @@
     if (client && client->matches(paintChunk))
       return std::move(client);
   }
 
   return wrapUnique(new ContentLayerClientImpl(
       paintChunk.id
           ? *paintChunk.id
           : paintArtifact.getDisplayItemList()[paintChunk.beginIndex].getId()));
 }
 
-scoped_refptr<cc::Layer> PaintArtifactCompositor::layerForPaintChunk(
+scoped_refptr<cc::Layer>
+PaintArtifactCompositor::compositedLayerForPendingLayer(
     const PaintArtifact& paintArtifact,
-    const PaintChunk& paintChunk,
+    const PendingLayer& pendingLayer,
     gfx::Vector2dF& layerOffset,
     Vector<std::unique_ptr<ContentLayerClientImpl>>& newContentLayerClients,
-    RasterInvalidationTracking* tracking) {
-  DCHECK(paintChunk.size());
+    RasterInvalidationTrackingMap<const PaintChunk>* trackingMap) {
+  DCHECK(pendingLayer.paintChunks.size());
+  const PaintChunk& firstPaintChunk = pendingLayer.paintChunks[0];
+  DCHECK(firstPaintChunk.size());
+#if DCHECK_IS_ON
+  for (const auto& paintChunk : pendingLayer.paintChunks) {
+    DCHECK(paintChunk.properties == firstPaintChunk.properties);
+  }
+#endif
 
   // If the paint chunk is a foreign layer, just return that layer.
-  if (scoped_refptr<cc::Layer> foreignLayer =
-          foreignLayerForPaintChunk(paintArtifact, paintChunk, layerOffset))
+  if (scoped_refptr<cc::Layer> foreignLayer = foreignLayerForPaintChunk(
+          paintArtifact, firstPaintChunk, layerOffset)) {
+    DCHECK(pendingLayer.paintChunks.size() == 1);
     return foreignLayer;
+  }
 
   // The common case: create or reuse a PictureLayer for painted content.
   std::unique_ptr<ContentLayerClientImpl> contentLayerClient =
-      clientForPaintChunk(paintChunk, paintArtifact);
+      clientForPaintChunk(firstPaintChunk, paintArtifact);
 
-  gfx::Rect combinedBounds = enclosingIntRect(paintChunk.bounds);
+  IntRect combinedBounds = enclosingIntRect(pendingLayer.bounds);
+  bool knownToBeOpaque = pendingLayer.knownToBeOpaque;
+  gfx::Rect ccCombinedBounds(combinedBounds);
+
   scoped_refptr<cc::DisplayItemList> displayList =
-      recordPaintChunk(paintArtifact, paintChunk, combinedBounds);
+      recordPaintChunk(paintArtifact, pendingLayer, ccCombinedBounds);
   contentLayerClient->SetDisplayList(std::move(displayList));
-  contentLayerClient->SetPaintableRegion(gfx::Rect(combinedBounds.size()));
+  contentLayerClient->SetPaintableRegion(gfx::Rect(ccCombinedBounds.size()));
 
-  layerOffset = combinedBounds.OffsetFromOrigin();
+  layerOffset = ccCombinedBounds.OffsetFromOrigin();
   scoped_refptr<cc::PictureLayer> ccPictureLayer =
       contentLayerClient->ccPictureLayer();
-  ccPictureLayer->SetBounds(combinedBounds.size());
+  ccPictureLayer->SetBounds(ccCombinedBounds.size());
   ccPictureLayer->SetIsDrawable(true);
-  if (paintChunk.knownToBeOpaque)
-    ccPictureLayer->SetContentsOpaque(true);
-  DCHECK(!tracking ||
-         tracking->trackedRasterInvalidations.size() ==
-             paintChunk.rasterInvalidationRects.size());
-  for (unsigned index = 0; index < paintChunk.rasterInvalidationRects.size();
-       ++index) {
-    IntRect rect(enclosingIntRect(paintChunk.rasterInvalidationRects[index]));
-    gfx::Rect ccInvalidationRect(rect.x(), rect.y(), std::max(0, rect.width()),
-                                 std::max(0, rect.height()));
-    // Raster paintChunk.rasterInvalidationRects is in the space of the
-    // containing transform node, so need to subtract off the layer offset.
-    ccInvalidationRect.Offset(-combinedBounds.OffsetFromOrigin());
-    contentLayerClient->setNeedsDisplayRect(
-        ccInvalidationRect,
-        tracking ? &tracking->trackedRasterInvalidations[index] : nullptr);
+  ccPictureLayer->SetContentsOpaque(knownToBeOpaque);
+  contentLayerClient->clearPaintChunkDebugData();
+
+  for (const auto& paintChunk : pendingLayer.paintChunks) {
+    RasterInvalidationTracking* rasterTracking =
+        trackingMap ? trackingMap->find(&paintChunk) : nullptr;
+    DCHECK(!rasterTracking ||
+           rasterTracking->trackedRasterInvalidations.size() ==
+               paintChunk.rasterInvalidationRects.size());
+    for (unsigned index = 0; index < paintChunk.rasterInvalidationRects.size();
+         ++index) {
+      IntRect rect(enclosingIntRect(paintChunk.rasterInvalidationRects[index]));
+      gfx::Rect ccInvalidationRect(rect.x(), rect.y(),
+                                   std::max(0, rect.width()),
+                                   std::max(0, rect.height()));
+      // Raster paintChunk.rasterInvalidationRects is in the space of the
+      // containing transform node, so need to subtract off the layer offset.
+      ccInvalidationRect.Offset(-ccCombinedBounds.OffsetFromOrigin());
+      contentLayerClient->setNeedsDisplayRect(
+          ccInvalidationRect,
+          rasterTracking ? &rasterTracking->trackedRasterInvalidations[index]
+                         : nullptr);
+    }
+    contentLayerClient->addPaintChunkDebugData(
+        paintArtifact.getDisplayItemList().subsequenceAsJSON(
+            paintChunk.beginIndex, paintChunk.endIndex, false, true));
   }
 
   newContentLayerClients.append(std::move(contentLayerClient));
   return ccPictureLayer;
 }
 
 namespace {
 
 class PropertyTreeManager {
   WTF_MAKE_NONCOPYABLE(PropertyTreeManager);
@@ skipping 395 matching lines @@
 
   dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
   dummyLayer->SetTransformTreeIndex(kSecondaryRootNodeId);
   dummyLayer->SetClipTreeIndex(outputClipId);
   dummyLayer->SetEffectTreeIndex(effectNode.id);
   dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
 }
 
 }  // namespace
 
+static bool canMergeInto(const PaintChunk& newChunk,
+                         const PendingLayer& candidatePendingLayer) {
+  DCHECK(candidatePendingLayer.paintChunks.size() >= 1);
+  const PaintChunk& firstLayerChunk = candidatePendingLayer.paintChunks[0];
+
+  PropertyTreeState newChunkProperties(
+      newChunk.properties.transform.get(), newChunk.properties.clip.get(),
+      newChunk.properties.effect.get(), newChunk.properties.scroll.get());
+
+  PropertyTreeState currentLayerProperties(
+      firstLayerChunk.properties.transform.get(),
+      firstLayerChunk.properties.clip.get(),
+      firstLayerChunk.properties.effect.get(),
+      firstLayerChunk.properties.scroll.get());
+
+  if (firstLayerChunk.properties.hasDirectCompositingReasons() ||
+      newChunk.properties.hasDirectCompositingReasons())
+    return false;
+
+  for (PropertyTreeStateIterator it(newChunkProperties); it.hasNext();
+       it.next()) {
+    if (it.current().hasDirectCompositingReasons())
+      return false;
+
+    if (it.current() == currentLayerProperties)
+      return true;
+  }
+  return false;
+}
+
+static bool overlaps(const PaintChunk& paintChunk,
+                     const PendingLayer& candidatePendingLayer,
+                     GeometryMapper& geometryMapper) {
+  PropertyTreeState rootPropertyTreeState(
+      TransformPaintPropertyNode::root(), ClipPaintPropertyNode::root(),
+      EffectPaintPropertyNode::root(), ScrollPaintPropertyNode::root());
+
+  FloatRect paintChunkScreenVisualRect(paintChunk.bounds);
+  PropertyTreeState paintChunkPropertyState(
+      paintChunk.properties.transform.get(), paintChunk.properties.clip.get(),
+      paintChunk.properties.effect.get(), paintChunk.properties.scroll.get());
+  bool success = false;
+  geometryMapper.localToVisualRectInAncestorSpace(
+      paintChunkScreenVisualRect, paintChunkPropertyState,
+      rootPropertyTreeState, success);
+  DCHECK(success);
+
+  PropertyTreeState candidatePendingLayerPropertyState(
+      candidatePendingLayer.paintChunks[0].properties.transform.get(),
+      candidatePendingLayer.paintChunks[0].properties.clip.get(),
+      candidatePendingLayer.paintChunks[0].properties.effect.get(),
+      candidatePendingLayer.paintChunks[0].properties.scroll.get());
+
+  FloatRect pendingLayerScreenVisualRect(candidatePendingLayer.bounds);
+  success = false;
+  geometryMapper.localToVisualRectInAncestorSpace(
+      pendingLayerScreenVisualRect, candidatePendingLayerPropertyState,
+      rootPropertyTreeState, success);
+  DCHECK(success);
+
+  return paintChunkScreenVisualRect.intersects(pendingLayerScreenVisualRect);
+  return true;
+}
+
+void PaintArtifactCompositor::collectPendingLayers(
+    const Vector<PaintChunk>& paintChunks,
+    Vector<PendingLayer>& pendingLayers) {
+  GeometryMapper geometryMapper;
+  for (const PaintChunk& paintChunk : paintChunks) {
+    bool createNew = true;
+    for (Vector<PendingLayer>::reverse_iterator candidatePendingLayer =
+             pendingLayers.rbegin();
+         candidatePendingLayer != pendingLayers.rend();
+         ++candidatePendingLayer) {
+      if (canMergeInto(paintChunk, *candidatePendingLayer)) {
+        candidatePendingLayer->add(paintChunk);
+        createNew = false;
+        break;
+      }
+      if (overlaps(paintChunk, *candidatePendingLayer, geometryMapper)) {
+        break;
+      }
+    }
+    if (createNew)
+      pendingLayers.append(PendingLayer(paintChunk));
+  }
+}
+
 void PaintArtifactCompositor::update(
     const PaintArtifact& paintArtifact,
     RasterInvalidationTrackingMap<const PaintChunk>* rasterChunkInvalidations) {
   DCHECK(m_rootLayer);
-
   cc::LayerTree* layerTree = m_rootLayer->GetLayerTree();
 
   // The tree will be null after detaching and this update can be ignored.
   // See: WebViewImpl::detachPaintArtifactCompositor().
   if (!layerTree)
     return;
 
   if (m_extraDataForTestingEnabled)
     m_extraDataForTesting = wrapUnique(new ExtraDataForTesting);
 
   m_rootLayer->RemoveAllChildren();
   m_rootLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
 
   PropertyTreeManager propertyTreeManager(*layerTree->property_trees(),
                                           m_rootLayer.get());
 
+  Vector<PendingLayer> pendingLayers;
+  collectPendingLayers(paintArtifact.paintChunks(), pendingLayers);
+
   Vector<std::unique_ptr<ContentLayerClientImpl>> newContentLayerClients;
   newContentLayerClients.reserveCapacity(paintArtifact.paintChunks().size());
-  for (const PaintChunk& paintChunk : paintArtifact.paintChunks()) {
+
+  for (const PendingLayer& pendingLayer : pendingLayers) {
     gfx::Vector2dF layerOffset;
-    scoped_refptr<cc::Layer> layer = layerForPaintChunk(
-        paintArtifact, paintChunk, layerOffset, newContentLayerClients,
-        rasterChunkInvalidations ? rasterChunkInvalidations->find(&paintChunk)
-                                 : nullptr);
+    scoped_refptr<cc::Layer> layer = compositedLayerForPendingLayer(
+        paintArtifact, pendingLayer, layerOffset, newContentLayerClients,
+        rasterChunkInvalidations);
 
     int transformId = propertyTreeManager.compositorIdForTransformNode(
-        paintChunk.properties.transform.get());
+        pendingLayer.paintChunks[0].properties.transform.get());
     int scrollId = propertyTreeManager.compositorIdForScrollNode(
-        paintChunk.properties.scroll.get());
+        pendingLayer.paintChunks[0].properties.scroll.get());
     int clipId = propertyTreeManager.compositorIdForClipNode(
-        paintChunk.properties.clip.get());
+        pendingLayer.paintChunks[0].properties.clip.get());
     int effectId = propertyTreeManager.switchToEffectNode(
-        *paintChunk.properties.effect.get());
+        *pendingLayer.paintChunks[0].properties.effect.get());
 
     propertyTreeManager.updateScrollOffset(layer->id(), scrollId);
 
     layer->set_offset_to_transform_parent(layerOffset);
 
     m_rootLayer->AddChild(layer);
     layer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
     layer->SetTransformTreeIndex(transformId);
     layer->SetClipTreeIndex(clipId);
     layer->SetEffectTreeIndex(effectId);
     layer->SetScrollTreeIndex(scrollId);
 
     // TODO(jbroman): This probably shouldn't be necessary, but it is still
     // queried by RenderSurfaceImpl.
     layer->Set3dSortingContextId(layerTree->property_trees()
                                      ->transform_tree.Node(transformId)
                                      ->sorting_context_id);
 
     layer->SetShouldCheckBackfaceVisibility(
-        paintChunk.properties.backfaceHidden);
+        pendingLayer.paintChunks[0].properties.backfaceHidden);
 
     if (m_extraDataForTestingEnabled)
       m_extraDataForTesting->contentLayers.append(layer);
   }
   m_contentLayerClients.clear();
   m_contentLayerClients.swap(newContentLayerClients);
 
   // Mark the property trees as having been rebuilt.
   layerTree->property_trees()->sequence_number = kPropertyTreeSequenceNumber;
   layerTree->property_trees()->needs_rebuild = false;
   layerTree->property_trees()->ResetCachedData();
 }
 
 }  // namespace blink