Factor PropertyTreeManager out of PaintArtifactCompositor.

third_party/WebKit/Source/platform/graphics/compositing/PropertyTreeManager.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/PropertyTreeManager.h"
+
+#include "cc/layers/layer.h"
+#include "cc/trees/clip_node.h"
+#include "cc/trees/effect_node.h"
+#include "cc/trees/property_tree.h"
+#include "cc/trees/scroll_node.h"
+#include "cc/trees/transform_node.h"
+#include "platform/graphics/paint/ClipPaintPropertyNode.h"
+#include "platform/graphics/paint/EffectPaintPropertyNode.h"
+#include "platform/graphics/paint/ScrollPaintPropertyNode.h"
+#include "platform/graphics/paint/TransformPaintPropertyNode.h"
+
+namespace blink {
+
+namespace {
+
+static constexpr int kInvalidNodeId = -1;
+// cc's property trees use 0 for the root node (always non-null).
+static constexpr int kRealRootNodeId = 0;
+// cc allocates special nodes for root effects such as the device scale.
+static constexpr int kSecondaryRootNodeId = 1;
+
+}  // namespace
+
+PropertyTreeManager::PropertyTreeManager(cc::PropertyTrees& propertyTrees,
+                                         cc::Layer* rootLayer)
+    : m_propertyTrees(propertyTrees), m_rootLayer(rootLayer) {
+  setupRootTransformNode();
+  setupRootClipNode();
+  setupRootEffectNode();
+  setupRootScrollNode();
+}
+
+cc::TransformTree& PropertyTreeManager::transformTree() {
+  return m_propertyTrees.transform_tree;
+}
+
+cc::ClipTree& PropertyTreeManager::clipTree() {
+  return m_propertyTrees.clip_tree;
+}
+
+cc::EffectTree& PropertyTreeManager::effectTree() {
+  return m_propertyTrees.effect_tree;
+}
+
+cc::ScrollTree& PropertyTreeManager::scrollTree() {
+  return m_propertyTrees.scroll_tree;
+}
+
+const EffectPaintPropertyNode* PropertyTreeManager::currentEffectNode() const {
+  return m_effectStack.back().effect;
+}
+
+void PropertyTreeManager::setupRootTransformNode() {
+  // cc is hardcoded to use transform node index 1 for device scale and
+  // transform.
+  cc::TransformTree& transformTree = m_propertyTrees.transform_tree;
+  transformTree.clear();
+  cc::TransformNode& transformNode = *transformTree.Node(
+      transformTree.Insert(cc::TransformNode(), kRealRootNodeId));
+  DCHECK_EQ(transformNode.id, kSecondaryRootNodeId);
+  transformNode.source_node_id = transformNode.parent_id;
+  transformTree.SetTargetId(transformNode.id, kRealRootNodeId);
+  transformTree.SetContentTargetId(transformNode.id, kRealRootNodeId);
+
+  // TODO(jaydasika): We shouldn't set ToScreen and FromScreen of root
+  // transform node here. They should be set while updating transform tree in
+  // cc.
+  float deviceScaleFactor = m_rootLayer->GetLayerTree()->device_scale_factor();
+  gfx::Transform toScreen;
+  toScreen.Scale(deviceScaleFactor, deviceScaleFactor);
+  transformTree.SetToScreen(kRealRootNodeId, toScreen);
+  gfx::Transform fromScreen;
+  bool invertible = toScreen.GetInverse(&fromScreen);
+  DCHECK(invertible);
+  transformTree.SetFromScreen(kRealRootNodeId, fromScreen);
+  transformTree.set_needs_update(true);
+
+  m_transformNodeMap.set(TransformPaintPropertyNode::root(), transformNode.id);
+  m_rootLayer->SetTransformTreeIndex(transformNode.id);
+}
+
+void PropertyTreeManager::setupRootClipNode() {
+  // cc is hardcoded to use clip node index 1 for viewport clip.
+  cc::ClipTree& clipTree = m_propertyTrees.clip_tree;
+  clipTree.clear();
+  m_propertyTrees.layer_id_to_clip_node_index.clear();
+  cc::ClipNode& clipNode =
+      *clipTree.Node(clipTree.Insert(cc::ClipNode(), kRealRootNodeId));
+  DCHECK_EQ(clipNode.id, kSecondaryRootNodeId);
+
+  clipNode.resets_clip = true;
+  clipNode.owning_layer_id = m_rootLayer->id();
+  clipNode.clip_type = cc::ClipNode::ClipType::APPLIES_LOCAL_CLIP;
+  clipNode.clip = gfx::RectF(
+      gfx::SizeF(m_rootLayer->GetLayerTree()->device_viewport_size()));
+  clipNode.transform_id = kRealRootNodeId;
+  clipNode.target_transform_id = kRealRootNodeId;
+  clipNode.target_effect_id = kSecondaryRootNodeId;
+  m_propertyTrees.layer_id_to_clip_node_index[clipNode.owning_layer_id] =
+      clipNode.id;
+
+  m_clipNodeMap.set(ClipPaintPropertyNode::root(), clipNode.id);
+  m_rootLayer->SetClipTreeIndex(clipNode.id);
+}
+
+void PropertyTreeManager::setupRootEffectNode() {
+  // cc is hardcoded to use effect node index 1 for root render surface.
+  cc::EffectTree& effectTree = m_propertyTrees.effect_tree;
+  effectTree.clear();
+  m_propertyTrees.layer_id_to_effect_node_index.clear();
+  cc::EffectNode& effectNode =
+      *effectTree.Node(effectTree.Insert(cc::EffectNode(), kInvalidNodeId));
+  DCHECK_EQ(effectNode.id, kSecondaryRootNodeId);
+  effectNode.owning_layer_id = m_rootLayer->id();
+  effectNode.transform_id = kRealRootNodeId;
+  effectNode.clip_id = kSecondaryRootNodeId;
+  effectNode.has_render_surface = true;
+  m_propertyTrees.layer_id_to_effect_node_index[effectNode.owning_layer_id] =
+      effectNode.id;
+
+  m_effectStack.push_back(
+      BlinkEffectAndCcIdPair{EffectPaintPropertyNode::root(), effectNode.id});
+  m_rootLayer->SetEffectTreeIndex(effectNode.id);
+}
+
+void PropertyTreeManager::setupRootScrollNode() {
+  cc::ScrollTree& scrollTree = m_propertyTrees.scroll_tree;
+  scrollTree.clear();
+  m_propertyTrees.layer_id_to_scroll_node_index.clear();
+  cc::ScrollNode& scrollNode =
+      *scrollTree.Node(scrollTree.Insert(cc::ScrollNode(), kRealRootNodeId));
+  DCHECK_EQ(scrollNode.id, kSecondaryRootNodeId);
+  scrollNode.owning_layer_id = m_rootLayer->id();
+  scrollNode.transform_id = kSecondaryRootNodeId;
+  m_propertyTrees.layer_id_to_scroll_node_index[scrollNode.owning_layer_id] =
+      scrollNode.id;
+
+  m_scrollNodeMap.set(ScrollPaintPropertyNode::root(), scrollNode.id);
+  m_rootLayer->SetScrollTreeIndex(scrollNode.id);
+}
+
+int PropertyTreeManager::ensureCompositorTransformNode(
+    const TransformPaintPropertyNode* transformNode) {
+  DCHECK(transformNode);
+  // TODO(crbug.com/645615): Remove the failsafe here.
+  if (!transformNode)
+    return kSecondaryRootNodeId;
+
+  auto it = m_transformNodeMap.find(transformNode);
+  if (it != m_transformNodeMap.end())
+    return it->value;
+
+  scoped_refptr<cc::Layer> dummyLayer = cc::Layer::Create();
+  int parentId = ensureCompositorTransformNode(transformNode->parent());
+  int id = transformTree().Insert(cc::TransformNode(), parentId);
+
+  cc::TransformNode& compositorNode = *transformTree().Node(id);
+  transformTree().SetTargetId(id, kRealRootNodeId);
+  transformTree().SetContentTargetId(id, kRealRootNodeId);
+  compositorNode.source_node_id = parentId;
+
+  FloatPoint3D origin = transformNode->origin();
+  compositorNode.pre_local.matrix().setTranslate(-origin.x(), -origin.y(),
+                                                 -origin.z());
+  compositorNode.local.matrix() =
+      TransformationMatrix::toSkMatrix44(transformNode->matrix());
+  compositorNode.post_local.matrix().setTranslate(origin.x(), origin.y(),
+                                                  origin.z());
+  compositorNode.needs_local_transform_update = true;
+  compositorNode.flattens_inherited_transform =
+      transformNode->flattensInheritedTransform();
+  compositorNode.sorting_context_id = transformNode->renderingContextId();
+
+  m_rootLayer->AddChild(dummyLayer);
+  dummyLayer->SetTransformTreeIndex(id);
+  dummyLayer->SetClipTreeIndex(kSecondaryRootNodeId);
+  dummyLayer->SetEffectTreeIndex(kSecondaryRootNodeId);
+  dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
+  dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
+
+  auto result = m_transformNodeMap.set(transformNode, id);
+  DCHECK(result.isNewEntry);
+  transformTree().set_needs_update(true);
+  return id;
+}
+
+int PropertyTreeManager::ensureCompositorClipNode(
+    const ClipPaintPropertyNode* clipNode) {
+  DCHECK(clipNode);
+  // TODO(crbug.com/645615): Remove the failsafe here.
+  if (!clipNode)
+    return kSecondaryRootNodeId;
+
+  auto it = m_clipNodeMap.find(clipNode);
+  if (it != m_clipNodeMap.end())
+    return it->value;
+
+  scoped_refptr<cc::Layer> dummyLayer = cc::Layer::Create();
+  int parentId = ensureCompositorClipNode(clipNode->parent());
+  int id = clipTree().Insert(cc::ClipNode(), parentId);
+
+  cc::ClipNode& compositorNode = *clipTree().Node(id);
+  compositorNode.owning_layer_id = dummyLayer->id();
+  m_propertyTrees.layer_id_to_clip_node_index[compositorNode.owning_layer_id] =
+      id;
+
+  // TODO(jbroman): Don't discard rounded corners.
+  compositorNode.clip = clipNode->clipRect().rect();
+  compositorNode.transform_id =
+      ensureCompositorTransformNode(clipNode->localTransformSpace());
+  compositorNode.target_transform_id = kRealRootNodeId;
+  compositorNode.target_effect_id = kSecondaryRootNodeId;
+  compositorNode.clip_type = cc::ClipNode::ClipType::APPLIES_LOCAL_CLIP;
+  compositorNode.layers_are_clipped = true;
+  compositorNode.layers_are_clipped_when_surfaces_disabled = true;
+
+  m_rootLayer->AddChild(dummyLayer);
+  dummyLayer->SetTransformTreeIndex(compositorNode.transform_id);
+  dummyLayer->SetClipTreeIndex(id);
+  dummyLayer->SetEffectTreeIndex(kSecondaryRootNodeId);
+  dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
+  dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
+
+  auto result = m_clipNodeMap.set(clipNode, id);
+  DCHECK(result.isNewEntry);
+  clipTree().set_needs_update(true);
+  return id;
+}
+
+int PropertyTreeManager::ensureCompositorScrollNode(
+    const ScrollPaintPropertyNode* scrollNode) {
+  DCHECK(scrollNode);
+  // TODO(crbug.com/645615): Remove the failsafe here.
+  if (!scrollNode)
+    return kSecondaryRootNodeId;
+
+  auto it = m_scrollNodeMap.find(scrollNode);
+  if (it != m_scrollNodeMap.end())
+    return it->value;
+
+  int parentId = ensureCompositorScrollNode(scrollNode->parent());
+  int id = scrollTree().Insert(cc::ScrollNode(), parentId);
+
+  cc::ScrollNode& compositorNode = *scrollTree().Node(id);
+  compositorNode.owning_layer_id = parentId;
+  m_propertyTrees
+      .layer_id_to_scroll_node_index[compositorNode.owning_layer_id] = id;
+
+  compositorNode.scrollable = true;
+
+  compositorNode.scroll_clip_layer_bounds.SetSize(scrollNode->clip().width(),
+                                                  scrollNode->clip().height());
+  compositorNode.bounds.SetSize(scrollNode->bounds().width(),
+                                scrollNode->bounds().height());
+  compositorNode.user_scrollable_horizontal =
+      scrollNode->userScrollableHorizontal();
+  compositorNode.user_scrollable_vertical =
+      scrollNode->userScrollableVertical();
+  compositorNode.transform_id =
+      ensureCompositorTransformNode(scrollNode->scrollOffsetTranslation());
+  compositorNode.main_thread_scrolling_reasons =
+      scrollNode->mainThreadScrollingReasons();
+
+  auto result = m_scrollNodeMap.set(scrollNode, id);
+  DCHECK(result.isNewEntry);
+  scrollTree().set_needs_update(true);
+
+  return id;
+}
+
+void PropertyTreeManager::updateScrollOffset(int layerId, int scrollId) {
+  cc::ScrollNode& scrollNode = *scrollTree().Node(scrollId);
+  cc::TransformNode& transformNode =
+      *transformTree().Node(scrollNode.transform_id);
+
+  transformNode.scrolls = true;
+
+  // Blink creates a 2d transform node just for scroll offset whereas cc's
+  // transform node has a special scroll offset field. To handle this we
+  // adjust cc's transform node to remove the 2d scroll translation and
+  // let the cc scroll tree update the cc scroll offset.
+  DCHECK(transformNode.local.IsIdentityOr2DTranslation());
+  auto offset = transformNode.local.To2dTranslation();
+  transformNode.local.MakeIdentity();
+  scrollTree().SetScrollOffset(layerId,
+                               gfx::ScrollOffset(-offset.x(), -offset.y()));
+  scrollTree().set_needs_update(true);
+}
+
+namespace {
+
+unsigned depth(const EffectPaintPropertyNode* node) {
+  unsigned result = 0;
+  for (; node; node = node->parent())
+    result++;
+  return result;
+}
+
+// TODO(chrishtr): templatize this to avoid duplication of
+// GeometryMapper::leastCommonAncestor.
+const EffectPaintPropertyNode* lowestCommonAncestor(
+    const EffectPaintPropertyNode* nodeA,
+    const EffectPaintPropertyNode* nodeB) {
+  // Optimized common case.
+  if (nodeA == nodeB)
+    return nodeA;
+
+  unsigned depthA = depth(nodeA), depthB = depth(nodeB);
+  while (depthA > depthB) {
+    nodeA = nodeA->parent();
+    depthA--;
+  }
+  while (depthB > depthA) {
+    nodeB = nodeB->parent();
+    depthB--;
+  }
+  DCHECK_EQ(depthA, depthB);
+  while (nodeA != nodeB) {
+    nodeA = nodeA->parent();
+    nodeB = nodeB->parent();
+  }
+  return nodeA;
+}
+
+}  // namespace
+
+int PropertyTreeManager::switchToEffectNode(
+    const EffectPaintPropertyNode& nextEffect) {
+  const EffectPaintPropertyNode* ancestor =
+      lowestCommonAncestor(currentEffectNode(), &nextEffect);
+  DCHECK(ancestor) << "Malformed effect tree. All nodes must be descendant of "
+                      "EffectPaintPropertyNode::root().";
+  while (currentEffectNode() != ancestor)
+    m_effectStack.pop_back();
+
+  // Now the current effect is the lowest common ancestor of previous effect
+  // and the next effect. That implies it is an existing node that already has
+  // at least one paint chunk or child effect, and we are going to either attach
+  // another paint chunk or child effect to it. We can no longer omit render
+  // surface for it even for opacity-only nodes.
+  // See comments in PropertyTreeManager::buildEffectNodesRecursively().
+  // TODO(crbug.com/504464): Remove premature optimization here.
+  if (currentEffectNode() && currentEffectNode()->opacity() != 1.f) {
+    effectTree()
+        .Node(getCurrentCompositorEffectNodeIndex())
+        ->has_render_surface = true;
+  }
+
+  buildEffectNodesRecursively(&nextEffect);
+
+  return getCurrentCompositorEffectNodeIndex();
+}
+
+void PropertyTreeManager::buildEffectNodesRecursively(
+    const EffectPaintPropertyNode* nextEffect) {
+  if (nextEffect == currentEffectNode())
+    return;
+  DCHECK(nextEffect);
+
+  buildEffectNodesRecursively(nextEffect->parent());
+  DCHECK_EQ(nextEffect->parent(), currentEffectNode());
+
+#if DCHECK_IS_ON()
+  DCHECK(!m_effectNodesConverted.contains(nextEffect))
+      << "Malformed paint artifact. Paint chunks under the same effect should "
+         "be contiguous.";
+  m_effectNodesConverted.add(nextEffect);
+#endif
+
+  // An effect node can't omit render surface if it has child with exotic
+  // blending mode. See comments below for more detail.
+  // TODO(crbug.com/504464): Remove premature optimization here.
+  if (nextEffect->blendMode() != SkBlendMode::kSrcOver) {
+    effectTree()
+        .Node(getCurrentCompositorEffectNodeIndex())
+        ->has_render_surface = true;
+  }
+
+  // We currently create dummy layers to host effect nodes and corresponding
+  // render surfaces. This should be removed once cc implements better support
+  // for freestanding property trees.
+  scoped_refptr<cc::Layer> dummyLayer = nextEffect->ensureDummyLayer();
+  m_rootLayer->AddChild(dummyLayer);
+
+  int outputClipId = ensureCompositorClipNode(nextEffect->outputClip());
+
+  cc::EffectNode& effectNode = *effectTree().Node(effectTree().Insert(
+      cc::EffectNode(), getCurrentCompositorEffectNodeIndex()));
+  effectNode.owning_layer_id = dummyLayer->id();
+  effectNode.clip_id = outputClipId;
+  // Every effect is supposed to have render surface enabled for grouping,
+  // but we can get away without one if the effect is opacity-only and has only
+  // one compositing child with kSrcOver blend mode. This is both for
+  // optimization and not introducing sub-pixel differences in layout tests.
+  // See PropertyTreeManager::switchToEffectNode() and above where we
+  // retrospectively enable render surface when more than one compositing child
+  // or a child with exotic blend mode is detected.
+  // TODO(crbug.com/504464): There is ongoing work in cc to delay render surface
+  // decision until later phase of the pipeline. Remove premature optimization
+  // here once the work is ready.
+  if (!nextEffect->filter().isEmpty() ||
+      nextEffect->blendMode() != SkBlendMode::kSrcOver)
+    effectNode.has_render_surface = true;
+  effectNode.opacity = nextEffect->opacity();
+  effectNode.filters = nextEffect->filter().asCcFilterOperations();
+  effectNode.blend_mode = nextEffect->blendMode();
+  m_propertyTrees.layer_id_to_effect_node_index[effectNode.owning_layer_id] =
+      effectNode.id;
+  m_effectStack.push_back(BlinkEffectAndCcIdPair{nextEffect, effectNode.id});
+
+  dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
+  dummyLayer->SetTransformTreeIndex(kSecondaryRootNodeId);
+  dummyLayer->SetClipTreeIndex(outputClipId);
+  dummyLayer->SetEffectTreeIndex(effectNode.id);
+  dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
+}
+
+}  // namespace blink