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// Copyright 2010 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 <set>
#include <string>
#include <vector>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/observer_list.h"
#include "cc/animation/layer_animation_controller.h"
#include "cc/animation/layer_animation_value_observer.h"
#include "cc/animation/layer_animation_value_provider.h"
#include "cc/base/cc_export.h"
#include "cc/base/region.h"
#include "cc/base/scoped_ptr_vector.h"
#include "cc/debug/frame_timing_request.h"
#include "cc/debug/micro_benchmark.h"
#include "cc/layers/layer_lists.h"
#include "cc/layers/layer_position_constraint.h"
#include "cc/layers/paint_properties.h"
#include "cc/layers/scroll_blocks_on.h"
#include "cc/output/filter_operations.h"
#include "cc/trees/property_tree.h"
#include "skia/ext/refptr.h"
#include "third_party/skia/include/core/SkColor.h"
#include "third_party/skia/include/core/SkImageFilter.h"
#include "third_party/skia/include/core/SkPicture.h"
#include "third_party/skia/include/core/SkXfermode.h"
#include "ui/gfx/geometry/point3_f.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/scroll_offset.h"
#include "ui/gfx/transform.h"
namespace gfx {
class BoxF;
namespace base {
namespace trace_event {
class ConvertableToTraceFormat;
namespace cc {
class Animation;
class AnimationDelegate;
struct AnimationEvent;
class CopyOutputRequest;
class LayerAnimationEventObserver;
class LayerClient;
class LayerImpl;
class LayerSettings;
class LayerTreeHost;
class LayerTreeHostCommon;
class LayerTreeImpl;
class LayerTreeSettings;
class RenderingStatsInstrumentation;
class ResourceUpdateQueue;
class ScrollbarLayerInterface;
class SimpleEnclosedRegion;
struct AnimationEvent;
// Base class for composited layers. Special layer types are derived from
// this class.
class CC_EXPORT Layer : public base::RefCounted<Layer>,
public LayerAnimationValueObserver,
public LayerAnimationValueProvider {
typedef LayerList LayerListType;
enum LayerIdLabels {
static scoped_refptr<Layer> Create(const LayerSettings& settings);
int id() const { return layer_id_; }
Layer* RootLayer();
Layer* parent() { return parent_; }
const Layer* parent() const { return parent_; }
void AddChild(scoped_refptr<Layer> child);
void InsertChild(scoped_refptr<Layer> child, size_t index);
void ReplaceChild(Layer* reference, scoped_refptr<Layer> new_layer);
void RemoveFromParent();
void RemoveAllChildren();
void SetChildren(const LayerList& children);
bool HasAncestor(const Layer* ancestor) const;
const LayerList& children() const { return children_; }
Layer* child_at(size_t index) { return children_[index].get(); }
// This requests the layer and its subtree be rendered and given to the
// callback. If the copy is unable to be produced (the layer is destroyed
// first), then the callback is called with a nullptr/empty result. If the
// request's source property is set, any prior uncommitted requests having the
// same source will be aborted.
void RequestCopyOfOutput(scoped_ptr<CopyOutputRequest> request);
bool HasCopyRequest() const {
return !copy_requests_.empty();
virtual void SetBackgroundColor(SkColor background_color);
SkColor background_color() const { return background_color_; }
// If contents_opaque(), return an opaque color else return a
// non-opaque color. Tries to return background_color(), if possible.
SkColor SafeOpaqueBackgroundColor() const;
// A layer's bounds are in logical, non-page-scaled pixels (however, the
// root layer's bounds are in physical pixels).
void SetBounds(const gfx::Size& bounds);
gfx::Size bounds() const { return bounds_; }
void SetMasksToBounds(bool masks_to_bounds);
bool masks_to_bounds() const { return masks_to_bounds_; }
void SetMaskLayer(Layer* mask_layer);
Layer* mask_layer() { return mask_layer_.get(); }
const Layer* mask_layer() const { return mask_layer_.get(); }
virtual void SetNeedsDisplayRect(const gfx::Rect& dirty_rect);
void SetNeedsDisplay() { SetNeedsDisplayRect(gfx::Rect(bounds())); }
void SetOpacity(float opacity);
float opacity() const { return opacity_; }
bool OpacityIsAnimating() const;
bool HasPotentiallyRunningOpacityAnimation() const;
virtual bool OpacityCanAnimateOnImplThread() const;
void SetBlendMode(SkXfermode::Mode blend_mode);
SkXfermode::Mode blend_mode() const { return blend_mode_; }
void set_draw_blend_mode(SkXfermode::Mode blend_mode) {
if (draw_blend_mode_ == blend_mode)
draw_blend_mode_ = blend_mode;
SkXfermode::Mode draw_blend_mode() const { return draw_blend_mode_; }
bool uses_default_blend_mode() const {
return blend_mode_ == SkXfermode::kSrcOver_Mode;
// A layer is root for an isolated group when it and all its descendants are
// drawn over a black and fully transparent background, creating an isolated
// group. It should be used along with SetBlendMode(), in order to restrict
// layers within the group to blend with layers outside this group.
void SetIsRootForIsolatedGroup(bool root);
bool is_root_for_isolated_group() const {
return is_root_for_isolated_group_;
void SetFilters(const FilterOperations& filters);
const FilterOperations& filters() const { return filters_; }
bool FilterIsAnimating() const;
bool HasPotentiallyRunningFilterAnimation() const;
// Background filters are filters applied to what is behind this layer, when
// they are viewed through non-opaque regions in this layer. They are used
// through the WebLayer interface, and are not exposed to HTML.
void SetBackgroundFilters(const FilterOperations& filters);
const FilterOperations& background_filters() const {
return background_filters_;
virtual void SetContentsOpaque(bool opaque);
bool contents_opaque() const { return contents_opaque_; }
void SetPosition(const gfx::PointF& position);
gfx::PointF position() const { return position_; }
// A layer that is a container for fixed position layers cannot be both
// scrollable and have a non-identity transform.
void SetIsContainerForFixedPositionLayers(bool container);
bool IsContainerForFixedPositionLayers() const;
gfx::Vector2dF FixedContainerSizeDelta() const {
return gfx::Vector2dF();
void SetPositionConstraint(const LayerPositionConstraint& constraint);
const LayerPositionConstraint& position_constraint() const {
return position_constraint_;
void SetTransform(const gfx::Transform& transform);
const gfx::Transform& transform() const { return transform_; }
bool TransformIsAnimating() const;
bool HasPotentiallyRunningTransformAnimation() const;
bool HasOnlyTranslationTransforms() const;
bool AnimationsPreserveAxisAlignment() const;
bool transform_is_invertible() const { return transform_is_invertible_; }
bool MaximumTargetScale(float* max_scale) const;
bool AnimationStartScale(float* start_scale) const;
void SetTransformOrigin(const gfx::Point3F&);
gfx::Point3F transform_origin() const { return transform_origin_; }
bool HasAnyAnimationTargetingProperty(
Animation::TargetProperty property) const;
bool ScrollOffsetAnimationWasInterrupted() const;
void SetScrollParent(Layer* parent);
Layer* scroll_parent() { return scroll_parent_; }
const Layer* scroll_parent() const { return scroll_parent_; }
void AddScrollChild(Layer* child);
void RemoveScrollChild(Layer* child);
std::set<Layer*>* scroll_children() { return scroll_children_.get(); }
const std::set<Layer*>* scroll_children() const {
return scroll_children_.get();
void SetClipParent(Layer* ancestor);
Layer* clip_parent() { return clip_parent_; }
const Layer* clip_parent() const {
return clip_parent_;
void AddClipChild(Layer* child);
void RemoveClipChild(Layer* child);
std::set<Layer*>* clip_children() { return clip_children_.get(); }
const std::set<Layer*>* clip_children() const {
return clip_children_.get();
// TODO(enne): Fix style here (and everywhere) once LayerImpl does the same.
gfx::Transform draw_transform() const;
gfx::Transform screen_space_transform() const;
void set_num_unclipped_descendants(size_t descendants) {
num_unclipped_descendants_ = descendants;
size_t num_unclipped_descendants() const {
return num_unclipped_descendants_;
void SetScrollOffset(const gfx::ScrollOffset& scroll_offset);
void SetScrollCompensationAdjustment(
const gfx::Vector2dF& scroll_compensation_adjustment);
gfx::Vector2dF ScrollCompensationAdjustment() const;
gfx::ScrollOffset scroll_offset() const { return scroll_offset_; }
void SetScrollOffsetFromImplSide(const gfx::ScrollOffset& scroll_offset);
void SetScrollClipLayerId(int clip_layer_id);
bool scrollable() const { return scroll_clip_layer_id_ != INVALID_ID; }
void SetUserScrollable(bool horizontal, bool vertical);
bool user_scrollable_horizontal() const {
return user_scrollable_horizontal_;
bool user_scrollable_vertical() const { return user_scrollable_vertical_; }
void SetShouldScrollOnMainThread(bool should_scroll_on_main_thread);
bool should_scroll_on_main_thread() const {
return should_scroll_on_main_thread_;
void SetHaveWheelEventHandlers(bool have_wheel_event_handlers);
bool have_wheel_event_handlers() const { return have_wheel_event_handlers_; }
void SetHaveScrollEventHandlers(bool have_scroll_event_handlers);
bool have_scroll_event_handlers() const {
return have_scroll_event_handlers_;
void SetNonFastScrollableRegion(const Region& non_fast_scrollable_region);
const Region& non_fast_scrollable_region() const {
return non_fast_scrollable_region_;
void SetTouchEventHandlerRegion(const Region& touch_event_handler_region);
const Region& touch_event_handler_region() const {
return touch_event_handler_region_;
void SetScrollBlocksOn(ScrollBlocksOn scroll_blocks_on);
ScrollBlocksOn scroll_blocks_on() const { return scroll_blocks_on_; }
void set_did_scroll_callback(const base::Closure& callback) {
did_scroll_callback_ = callback;
void SetForceRenderSurface(bool force_render_surface);
bool force_render_surface() const { return force_render_surface_; }
gfx::Vector2dF ScrollDelta() const { return gfx::Vector2dF(); }
gfx::ScrollOffset CurrentScrollOffset() const { return scroll_offset_; }
void SetDoubleSided(bool double_sided);
bool double_sided() const { return double_sided_; }
void SetShouldFlattenTransform(bool flatten);
bool should_flatten_transform() const { return should_flatten_transform_; }
bool Is3dSorted() const { return sorting_context_id_ != 0; }
void set_use_parent_backface_visibility(bool use) {
use_parent_backface_visibility_ = use;
bool use_parent_backface_visibility() const {
return use_parent_backface_visibility_;
virtual void SetLayerTreeHost(LayerTreeHost* host);
virtual bool HasDelegatedContent() const;
bool HasContributingDelegatedRenderPasses() const { return false; }
void SetIsDrawable(bool is_drawable);
void SetHideLayerAndSubtree(bool hide);
bool hide_layer_and_subtree() const { return hide_layer_and_subtree_; }
void SetReplicaLayer(Layer* layer);
Layer* replica_layer() { return replica_layer_.get(); }
const Layer* replica_layer() const { return replica_layer_.get(); }
bool has_mask() const { return !!mask_layer_.get(); }
bool has_replica() const { return !!replica_layer_.get(); }
bool replica_has_mask() const {
return replica_layer_.get() &&
(mask_layer_.get() || replica_layer_->mask_layer_.get());
int NumDescendantsThatDrawContent() const;
// This is only virtual for tests.
// TODO(awoloszyn): Remove this once we no longer need it for tests
virtual bool DrawsContent() const;
// This methods typically need to be overwritten by derived classes.
virtual void SavePaintProperties();
// Returns true iff anything was updated that needs to be committed.
virtual bool Update();
virtual void SetIsMask(bool is_mask) {}
virtual bool IsSuitableForGpuRasterization() const;
virtual scoped_refptr<base::trace_event::ConvertableToTraceFormat>
void SetLayerClient(LayerClient* client) { client_ = client; }
virtual void PushPropertiesTo(LayerImpl* layer);
LayerTreeHost* layer_tree_host() { return layer_tree_host_; }
const LayerTreeHost* layer_tree_host() const { return layer_tree_host_; }
bool AddAnimation(scoped_ptr<Animation> animation);
void PauseAnimation(int animation_id, double time_offset);
void RemoveAnimation(int animation_id);
void RemoveAnimation(int animation_id, Animation::TargetProperty property);
LayerAnimationController* layer_animation_controller() const {
return layer_animation_controller_.get();
void SetLayerAnimationControllerForTest(
scoped_refptr<LayerAnimationController> controller);
void set_layer_animation_delegate(AnimationDelegate* delegate) {
bool HasActiveAnimation() const;
void RegisterForAnimations(AnimationRegistrar* registrar);
void AddLayerAnimationEventObserver(
LayerAnimationEventObserver* animation_observer);
void RemoveLayerAnimationEventObserver(
LayerAnimationEventObserver* animation_observer);
virtual ScrollbarLayerInterface* ToScrollbarLayer();
virtual skia::RefPtr<SkPicture> GetPicture() const;
// Constructs a LayerImpl of the correct runtime type for this Layer type.
virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl);
bool NeedsDisplayForTesting() const { return !update_rect_.IsEmpty(); }
void ResetNeedsDisplayForTesting() { update_rect_ = gfx::Rect(); }
RenderingStatsInstrumentation* rendering_stats_instrumentation() const;
const PaintProperties& paint_properties() const {
return paint_properties_;
void SetNeedsPushProperties();
bool needs_push_properties() const { return needs_push_properties_; }
bool descendant_needs_push_properties() const {
return num_dependents_need_push_properties_ > 0;
void reset_needs_push_properties_for_testing() {
needs_push_properties_ = false;
virtual void RunMicroBenchmark(MicroBenchmark* benchmark);
void Set3dSortingContextId(int id);
int sorting_context_id() const { return sorting_context_id_; }
void set_property_tree_sequence_number(int sequence_number) {
property_tree_sequence_number_ = sequence_number;
void SetTransformTreeIndex(int index);
int transform_tree_index() const;
void SetClipTreeIndex(int index);
int clip_tree_index() const;
void SetEffectTreeIndex(int index);
int effect_tree_index() const;
void set_offset_to_transform_parent(gfx::Vector2dF offset) {
if (offset_to_transform_parent_ == offset)
offset_to_transform_parent_ = offset;
gfx::Vector2dF offset_to_transform_parent() const {
return offset_to_transform_parent_;
// TODO(enne): Once LayerImpl only uses property trees, remove these
// functions.
const gfx::Rect& visible_rect_from_property_trees() const {
return visible_layer_rect();
void set_visible_rect_from_property_trees(const gfx::Rect& rect) {
const gfx::Rect& clip_rect_in_target_space_from_property_trees() const {
return clip_rect();
void set_clip_rect_in_target_space_from_property_trees(
const gfx::Rect& rect) {
// TODO(enne): This needs a different name. It is a calculated value
// from the property tree builder and not a synonym for "should
// flatten transform".
void set_should_flatten_transform_from_property_tree(bool should_flatten) {
if (should_flatten_transform_from_property_tree_ == should_flatten)
should_flatten_transform_from_property_tree_ = should_flatten;
bool should_flatten_transform_from_property_tree() const {
return should_flatten_transform_from_property_tree_;
const gfx::Rect& visible_layer_rect() const { return visible_layer_rect_; }
void set_visible_layer_rect(const gfx::Rect& rect) {
visible_layer_rect_ = rect;
const gfx::Rect& clip_rect() const { return clip_rect_; }
void set_clip_rect(const gfx::Rect& rect) { clip_rect_ = rect; }
void set_is_clipped(bool is_clipped) {
if (is_clipped_ == is_clipped)
is_clipped_ = is_clipped;
bool is_clipped() const { return is_clipped_; }
bool has_render_surface() const {
return has_render_surface_;
// Sets new frame timing requests for this layer.
void SetFrameTimingRequests(const std::vector<FrameTimingRequest>& requests);
// Accessor for unit tests
const std::vector<FrameTimingRequest>& FrameTimingRequests() const {
return frame_timing_requests_;
void DidBeginTracing();
void set_num_layer_or_descendant_with_copy_request(
int num_layer_or_descendants_with_copy_request) {
num_layer_or_descendants_with_copy_request_ =
int num_layer_or_descendants_with_copy_request() {
return num_layer_or_descendants_with_copy_request_;
void set_visited(bool visited);
bool visited();
void set_layer_or_descendant_is_drawn(bool layer_or_descendant_is_drawn);
bool layer_or_descendant_is_drawn();
void set_sorted_for_recursion(bool sorted_for_recursion);
bool sorted_for_recursion();
friend class LayerImpl;
friend class TreeSynchronizer;
~Layer() override;
explicit Layer(const LayerSettings& settings);
// These SetNeeds functions are in order of severity of update:
// Called when this layer has been modified in some way, but isn't sure
// that it needs a commit yet. It needs CalcDrawProperties and UpdateLayers
// before it knows whether or not a commit is required.
void SetNeedsUpdate();
// Called when a property has been modified in a way that the layer
// knows immediately that a commit is required. This implies SetNeedsUpdate
// as well as SetNeedsPushProperties to push that property.
void SetNeedsCommit();
// This is identical to SetNeedsCommit, but the former requests a rebuild of
// the property trees.
void SetNeedsCommitNoRebuild();
// Called when there's been a change in layer structure. Implies both
// SetNeedsUpdate and SetNeedsCommit, but not SetNeedsPushProperties.
void SetNeedsFullTreeSync();
// Called when the next commit should wait until the pending tree is activated
// before finishing the commit and unblocking the main thread. Used to ensure
// unused resources on the impl thread are returned before commit completes.
void SetNextCommitWaitsForActivation();
// Will recalculate whether the layer draws content and set draws_content_
// appropriately.
void UpdateDrawsContent(bool has_drawable_content);
virtual bool HasDrawableContent() const;
// Called when the layer's number of drawable descendants changes.
void AddDrawableDescendants(int num);
void AddDependentNeedsPushProperties();
void RemoveDependentNeedsPushProperties();
bool parent_should_know_need_push_properties() const {
return needs_push_properties() || descendant_needs_push_properties();
bool IsPropertyChangeAllowed() const;
// This flag is set when the layer needs to push properties to the impl
// side.
bool needs_push_properties_;
// The number of direct children or dependent layers that need to be recursed
// to in order for them or a descendent of them to push properties to the impl
// side.
int num_dependents_need_push_properties_;
// Tracks whether this layer may have changed stacking order with its
// siblings.
bool stacking_order_changed_;
// The update rect is the region of the compositor resource that was
// actually updated by the compositor. For layers that may do updating
// outside the compositor's control (i.e. plugin layers), this information
// is not available and the update rect will remain empty.
// Note this rect is in layer space (not content space).
gfx::Rect update_rect_;
scoped_refptr<Layer> mask_layer_;
int layer_id_;
// When true, the layer is about to perform an update. Any commit requests
// will be handled implicitly after the update completes.
bool ignore_set_needs_commit_;
// Layers that share a sorting context id will be sorted together in 3d
// space. 0 is a special value that means this layer will not be sorted and
// will be drawn in paint order.
int sorting_context_id_;
friend class base::RefCounted<Layer>;
friend class LayerTreeHostCommon;
void SetParent(Layer* layer);
bool DescendantIsFixedToContainerLayer() const;
// This should only be called during BeginMainFrame since it does not
// trigger a Commit.
void SetHasRenderSurface(bool has_render_surface);
// This should only be called from RemoveFromParent().
void RemoveChildOrDependent(Layer* child);
// LayerAnimationValueProvider implementation.
gfx::ScrollOffset ScrollOffsetForAnimation() const override;
// LayerAnimationValueObserver implementation.
void OnFilterAnimated(const FilterOperations& filters) override;
void OnOpacityAnimated(float opacity) override;
void OnTransformAnimated(const gfx::Transform& transform) override;
void OnScrollOffsetAnimated(const gfx::ScrollOffset& scroll_offset) override;
void OnAnimationWaitingForDeletion() override;
void OnTransformIsPotentiallyAnimatingChanged(bool is_animating) override;
bool IsActive() const override;
// If this layer has a scroll parent, it removes |this| from its list of
// scroll children.
void RemoveFromScrollTree();
// If this layer has a clip parent, it removes |this| from its list of clip
// children.
void RemoveFromClipTree();
// When we detach or attach layer to new LayerTreeHost, all property trees'
// indices becomes invalid.
void InvalidatePropertyTreesIndices();
void UpdateNumCopyRequestsForSubtree(bool add);
LayerList children_;
Layer* parent_;
// Layer instances have a weak pointer to their LayerTreeHost.
// This pointer value is nil when a Layer is not in a tree and is
// updated via SetLayerTreeHost() if a layer moves between trees.
LayerTreeHost* layer_tree_host_;
scoped_refptr<LayerAnimationController> layer_animation_controller_;
// Layer properties.
gfx::Size bounds_;
gfx::ScrollOffset scroll_offset_;
gfx::Vector2dF scroll_compensation_adjustment_;
// This variable indicates which ancestor layer (if any) whose size,
// transformed relative to this layer, defines the maximum scroll offset for
// this layer.
int scroll_clip_layer_id_;
int num_descendants_that_draw_content_;
int transform_tree_index_;
int effect_tree_index_;
int clip_tree_index_;
int property_tree_sequence_number_;
int num_layer_or_descendants_with_copy_request_;
gfx::Vector2dF offset_to_transform_parent_;
bool should_flatten_transform_from_property_tree_ : 1;
bool is_clipped_ : 1;
bool should_scroll_on_main_thread_ : 1;
bool have_wheel_event_handlers_ : 1;
bool have_scroll_event_handlers_ : 1;
bool user_scrollable_horizontal_ : 1;
bool user_scrollable_vertical_ : 1;
bool is_root_for_isolated_group_ : 1;
bool is_container_for_fixed_position_layers_ : 1;
bool is_drawable_ : 1;
bool draws_content_ : 1;
bool hide_layer_and_subtree_ : 1;
bool masks_to_bounds_ : 1;
bool contents_opaque_ : 1;
bool double_sided_ : 1;
bool should_flatten_transform_ : 1;
bool use_parent_backface_visibility_ : 1;
bool force_render_surface_ : 1;
bool transform_is_invertible_ : 1;
bool has_render_surface_ : 1;
ScrollBlocksOn scroll_blocks_on_ : 3;
Region non_fast_scrollable_region_;
Region touch_event_handler_region_;
gfx::PointF position_;
SkColor background_color_;
float opacity_;
SkXfermode::Mode blend_mode_;
// draw_blend_mode may be different than blend_mode_,
// when a RenderSurface re-parents the layer's blend_mode.
SkXfermode::Mode draw_blend_mode_;
FilterOperations filters_;
FilterOperations background_filters_;
LayerPositionConstraint position_constraint_;
Layer* scroll_parent_;
scoped_ptr<std::set<Layer*>> scroll_children_;
// The following three variables are tracker variables. They are bools
// wrapped inside an integer variable. If true, their value equals the
// LayerTreeHost's meta_information_sequence_number. This wrapping of bools
// inside ints is done to avoid a layer tree treewalk to reset their values.
int layer_or_descendant_is_drawn_tracker_;
int sorted_for_recursion_tracker_;
int visited_tracker_;
Layer* clip_parent_;
scoped_ptr<std::set<Layer*>> clip_children_;
gfx::Transform transform_;
gfx::Point3F transform_origin_;
// Replica layer used for reflections.
scoped_refptr<Layer> replica_layer_;
LayerClient* client_;
ScopedPtrVector<CopyOutputRequest> copy_requests_;
base::Closure did_scroll_callback_;
PaintProperties paint_properties_;
// These all act like draw properties, so don't need push properties.
gfx::Rect visible_layer_rect_;
gfx::Rect clip_rect_;
size_t num_unclipped_descendants_;
std::vector<FrameTimingRequest> frame_timing_requests_;
bool frame_timing_requests_dirty_;
} // namespace cc
#endif // CC_LAYERS_LAYER_H_