mix-blend-mode implementation for accelerated layers

cc/layers/layer_impl.cc

 // Copyright 2012 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 "cc/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/strings/stringprintf.h"
 #include "cc/animation/animation_registrar.h"
 #include "cc/animation/scrollbar_animation_controller.h"
@@ skipping 35 matching lines @@
       have_wheel_event_handlers_(false),
       user_scrollable_horizontal_(true),
       user_scrollable_vertical_(true),
       background_color_(0),
       stacking_order_changed_(false),
       double_sided_(true),
       layer_property_changed_(false),
       masks_to_bounds_(false),
       contents_opaque_(false),
       opacity_(1.0),
+      blend_mode_(SkXfermode::kSrcOver_Mode),
+      is_root_for_isolated_group_(false),
       preserves_3d_(false),
       use_parent_backface_visibility_(false),
       draw_checkerboard_for_missing_tiles_(false),
       draws_content_(false),
       hide_layer_and_subtree_(false),
       force_render_surface_(false),
       is_container_for_fixed_position_layers_(false),
       draw_depth_(0.f),
       compositing_reasons_(kCompositingReasonUnknown),
       current_draw_mode_(DRAW_MODE_NONE),
@@ skipping 173 matching lines @@
   draw_properties_.render_surface.reset();
 }
 
 scoped_ptr<SharedQuadState> LayerImpl::CreateSharedQuadState() const {
   scoped_ptr<SharedQuadState> state = SharedQuadState::Create();
   state->SetAll(draw_properties_.target_space_transform,
                 draw_properties_.content_bounds,
                 draw_properties_.visible_content_rect,
                 draw_properties_.clip_rect,
                 draw_properties_.is_clipped,
-                draw_properties_.opacity);
+                draw_properties_.opacity,
+                blend_mode_);
   return state.Pass();
 }
 
 bool LayerImpl::WillDraw(DrawMode draw_mode,
                          ResourceProvider* resource_provider) {
   // WillDraw/DidDraw must be matched.
   DCHECK_NE(DRAW_MODE_NONE, draw_mode);
   DCHECK_EQ(DRAW_MODE_NONE, current_draw_mode_);
   current_draw_mode_ = draw_mode;
   return true;
@@ skipping 257 matching lines @@
   layer->SetHideLayerAndSubtree(hide_layer_and_subtree_);
   layer->SetFilters(filters());
   layer->SetBackgroundFilters(background_filters());
   layer->SetMasksToBounds(masks_to_bounds_);
   layer->SetShouldScrollOnMainThread(should_scroll_on_main_thread_);
   layer->SetHaveWheelEventHandlers(have_wheel_event_handlers_);
   layer->SetNonFastScrollableRegion(non_fast_scrollable_region_);
   layer->SetTouchEventHandlerRegion(touch_event_handler_region_);
   layer->SetContentsOpaque(contents_opaque_);
   layer->SetOpacity(opacity_);
+  layer->SetBlendMode(blend_mode_);
+  layer->SetIsRootForIsolatedGroup(is_root_for_isolated_group_);
   layer->SetPosition(position_);
   layer->SetIsContainerForFixedPositionLayers(
       is_container_for_fixed_position_layers_);
   layer->SetFixedContainerSizeDelta(fixed_container_size_delta_);
   layer->SetPositionConstraint(position_constraint_);
   layer->SetPreserves3d(preserves_3d());
   layer->SetUseParentBackfaceVisibility(use_parent_backface_visibility_);
   layer->SetSublayerTransform(sublayer_transform_);
   layer->SetTransform(transform_);
 
@@ skipping 336 matching lines @@
 bool LayerImpl::OpacityIsAnimating() const {
   return layer_animation_controller_->IsAnimatingProperty(Animation::Opacity);
 }
 
 bool LayerImpl::OpacityIsAnimatingOnImplOnly() const {
   Animation* opacity_animation =
       layer_animation_controller_->GetAnimation(Animation::Opacity);
   return opacity_animation && opacity_animation->is_impl_only();
 }
 
+void LayerImpl::SetBlendMode(SkXfermode::Mode blend_mode) {
+  if (blend_mode_ == blend_mode)
+    return;
+
+  blend_mode_ = blend_mode;
+  NoteLayerPropertyChangedForSubtree();
+}
+
+void LayerImpl::SetIsRootForIsolatedGroup(bool root) {
+  if (is_root_for_isolated_group_ == root)
+    return;
+
+  is_root_for_isolated_group_ = root;
+  // Specifying the root for an isolated group does not affect the current
+  // layer; it affects only children.
+  NoteLayerPropertyChangedForDescendants();

[rosca, 2013/11/21 13:04:46]

enne: could you please take another look at this change? Do you think I should
change it to NoteLayerPropertyChangedForSubtree()? When a layer gets isolated it
doesn't change the way it looks. Only descendants having a blend mode can look
different, because they use the backdrop limited to this root.

[enne (OOO), 2013/11/21 18:15:59]

Hmm, on second thought this should be removed.  Making something an isolated
group promotes it to be a render surface, but that shouldn't change the way it
is being rendered.  We don't mark something as changed when we put a copy
request on it.

+}
+
 void LayerImpl::SetPosition(gfx::PointF position) {
   if (position_ == position)
     return;
 
   position_ = position;
   NoteLayerPropertyChangedForSubtree();
 }
 
 void LayerImpl::SetPreserves3d(bool preserves3_d) {
   if (preserves_3d_ == preserves3_d)
@@ skipping 381 matching lines @@
 
   if (reasons & kCompositingReasonLayerForMask)
     reason_list->AppendString("Is a mask layer");
 
   if (reasons & kCompositingReasonOverflowScrollingParent)
     reason_list->AppendString("Scroll parent is not an ancestor");
 
   if (reasons & kCompositingReasonOutOfFlowClipping)
     reason_list->AppendString("Has clipping ancestor");
 
+  if (reasons & kCompositingReasonIsolateCompositedDescendants)
+    reason_list->AppendString("Should isolate composited descendants");
+
   return reason_list.PassAs<base::Value>();
 }
 
 void LayerImpl::AsValueInto(base::DictionaryValue* state) const {
   TracedValue::MakeDictIntoImplicitSnapshot(state, LayerTypeAsString(), this);
   state->SetInteger("layer_id", id());
   state->SetString("layer_name", debug_name());
   state->Set("bounds", MathUtil::AsValue(bounds()).release());
   state->SetInteger("draws_content", DrawsContent());
   state->SetInteger("gpu_memory_usage", GPUMemoryUsageInBytes());
@@ skipping 55 matching lines @@
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   AsValueInto(state.get());
   return state.PassAs<base::Value>();
 }
 
 void LayerImpl::RunMicroBenchmark(MicroBenchmarkImpl* benchmark) {
   benchmark->RunOnLayer(this);
 }
 
 }  // namespace cc