Layer state stack

ci/licenses_golden/licenses_flutter

@@ -171,6 +171,8 @@ FILE: ../../../flutter/flow/layers/layer.cc
 FILE: ../../../flutter/flow/layers/layer.h
 FILE: ../../../flutter/flow/layers/layer_raster_cache_item.cc
 FILE: ../../../flutter/flow/layers/layer_raster_cache_item.h
+FILE: ../../../flutter/flow/layers/layer_state_stack.cc
+FILE: ../../../flutter/flow/layers/layer_state_stack.h
 FILE: ../../../flutter/flow/layers/layer_tree.cc
 FILE: ../../../flutter/flow/layers/layer_tree.h
 FILE: ../../../flutter/flow/layers/layer_tree_unittests.cc

display_list/display_list_color_filter.h

@@ -57,6 +57,11 @@ class DlColorFilter
   // pixels non-transparent and therefore expand the bounds.
   virtual bool modifies_transparent_black() const = 0;
 
+  // Return a boolean indicating whether the color filtering operation can
+  // be applied either before or after modulating the pixels with an opacity
+  // value without changing the operation.
+  virtual bool can_commute_with_alpha() const { return false; }
+
   // Return a DlBlendColorFilter pointer to this object iff it is a Blend
   // type of ColorFilter, otherwise return nullptr.
   virtual const DlBlendColorFilter* asBlend() const { return nullptr; }
@@ -150,6 +155,12 @@ class DlMatrixColorFilter final : public DlColorFilter {
            sk_filter->filterColor(SK_ColorTRANSPARENT) != SK_ColorTRANSPARENT;
   }
 
+  bool can_commute_with_alpha() const override {
+    return matrix_[3] == 0 && matrix_[8] == 0 && matrix_[13] == 0 &&
+           matrix_[15] == 0 && matrix_[16] == 0 && matrix_[17] == 0 &&
+           (matrix_[18] >= 0.0 && matrix_[18] <= 1.0) && matrix_[19] == 0;
+  }
+
   std::shared_ptr<DlColorFilter> shared() const override {
     return std::make_shared<DlMatrixColorFilter>(this);
   }

display_list/display_list_paint.h

@@ -104,6 +104,10 @@ class DlPaint {
     color_.argb = alpha << 24 | (color_.argb & 0x00FFFFFF);
     return *this;
   }
+  DlPaint& setOpacity(SkScalar opacity) {
+    setAlpha(SkScalarRoundToInt(opacity * 0xff));
+    return *this;
+  }
 
   DlBlendMode getBlendMode() const {
     return static_cast<DlBlendMode>(blendMode_);
@@ -166,7 +170,7 @@ class DlPaint {
     return colorFilter_;
   }
   const DlColorFilter* getColorFilterPtr() const { return colorFilter_.get(); }
-  DlPaint& setColorFilter(std::shared_ptr<DlColorFilter> filter) {
+  DlPaint& setColorFilter(const std::shared_ptr<const DlColorFilter> filter) {
     colorFilter_ = filter ? filter->shared() : nullptr;
     return *this;
   }
@@ -179,7 +183,7 @@ class DlPaint {
     return imageFilter_;
   }
   const DlImageFilter* getImageFilterPtr() const { return imageFilter_.get(); }
-  DlPaint& setImageFilter(std::shared_ptr<DlImageFilter> filter) {
+  DlPaint& setImageFilter(const std::shared_ptr<const DlImageFilter> filter) {
     imageFilter_ = filter;
     return *this;
   }

display_list/display_list_utils.cc

@@ -19,15 +19,6 @@
 
 namespace flutter {
 
-// clang-format off
-constexpr float kInvertColorMatrix[20] = {
-  -1.0,    0,    0, 1.0, 0,
-     0, -1.0,    0, 1.0, 0,
-     0,    0, -1.0, 1.0, 0,
-   1.0,  1.0,  1.0, 1.0, 0
-};
-// clang-format on
-
 void SkPaintDispatchHelper::save_opacity(SkScalar child_opacity) {
   save_stack_.emplace_back(opacity_);
   set_opacity(child_opacity);
@@ -96,13 +87,19 @@ void SkPaintDispatchHelper::setMaskFilter(const DlMaskFilter* filter) {
 }
 
 sk_sp<SkColorFilter> SkPaintDispatchHelper::makeColorFilter() const {
-  if (!invert_colors_) {
-    return color_filter_ ? color_filter_->skia_object() : nullptr;
+  return MakeColorFilter(invert_colors_, color_filter_.get());
+}
+
+sk_sp<SkColorFilter> SkPaintDispatchHelper::MakeColorFilter(
+    bool isInvertColors,
+    const DlColorFilter* color_filter) {
+  if (!isInvertColors) {
+    return color_filter ? color_filter->skia_object() : nullptr;
   }
   sk_sp<SkColorFilter> invert_filter =
       SkColorFilters::Matrix(kInvertColorMatrix);
-  if (color_filter_) {
-    invert_filter = invert_filter->makeComposed(color_filter_->skia_object());
+  if (color_filter) {
+    invert_filter = invert_filter->makeComposed(color_filter->skia_object());
   }
   return invert_filter;
 }

display_list/display_list_utils.h

@@ -174,6 +174,18 @@ class SkPaintDispatchHelper : public virtual Dispatcher {
     }
   }
 
+  // clang-format off
+  static constexpr float kInvertColorMatrix[20] = {
+    -1.0,    0,    0, 1.0, 0,
+       0, -1.0,    0, 1.0, 0,
+       0,    0, -1.0, 1.0, 0,
+     1.0,  1.0,  1.0, 1.0, 0
+  };
+  // clang-format on
+  static sk_sp<SkColorFilter> MakeColorFilter(
+      bool isInvertColors,
+      const DlColorFilter* color_filter);
+
   void setAntiAlias(bool aa) override;
   void setDither(bool dither) override;
   void setStyle(DlDrawStyle style) override;

flow/BUILD.gn

@@ -45,6 +45,8 @@ source_set("flow") {
     "layers/layer.h",
     "layers/layer_raster_cache_item.cc",
     "layers/layer_raster_cache_item.h",
+    "layers/layer_state_stack.cc",
+    "layers/layer_state_stack.h",
     "layers/layer_tree.cc",
     "layers/layer_tree.h",
     "layers/offscreen_surface.cc",

flow/layers/backdrop_filter_layer.cc

@@ -47,38 +47,17 @@ void BackdropFilterLayer::Preroll(PrerollContext* context,
   PrerollChildren(context, matrix, &child_paint_bounds);
   child_paint_bounds.join(context->cull_rect);
   set_paint_bounds(child_paint_bounds);
-  context->subtree_can_inherit_opacity = true;
+  context->renderable_state_flags = SAVE_LAYER_RENDER_FLAGS;
 }
 
 void BackdropFilterLayer::Paint(PaintContext& context) const {
   TRACE_EVENT0("flutter", "BackdropFilterLayer::Paint");
   FML_DCHECK(needs_painting(context));
 
-  AutoCachePaint save_paint(context);
-  save_paint.setBlendMode(blend_mode_);
-  if (context.leaf_nodes_builder) {
-    // Note that we perform a saveLayer directly on the
-    // leaf_nodes_builder here similar to how the SkCanvas
-    // path specifies the kLeafNodesCanvas below.
-    // See https:://flutter.dev/go/backdrop-filter-with-overlay-canvas
-    context.leaf_nodes_builder->saveLayer(&paint_bounds(),
-                                          save_paint.dl_paint(), filter_.get());
+  auto mutator = context.state_stack.save();
+  mutator.applyBackdropFilter(paint_bounds(), filter_, blend_mode_);
 
-    PaintChildren(context);
-
-    context.leaf_nodes_builder->restore();
-  } else {
-    auto sk_filter = filter_ ? filter_->skia_object() : nullptr;
-    Layer::AutoSaveLayer save = Layer::AutoSaveLayer::Create(
-        context,
-        SkCanvas::SaveLayerRec{&paint_bounds(), save_paint.sk_paint(),
-                               sk_filter.get(), 0},
-        // BackdropFilter should only happen on the leaf nodes canvas.
-        // See https:://flutter.dev/go/backdrop-filter-with-overlay-canvas
-        AutoSaveLayer::SaveMode::kLeafNodesCanvas);
-
-    PaintChildren(context);
-  }
+  PaintChildren(context);
 }
 
 }  // namespace flutter

flow/layers/backdrop_filter_layer_unittests.cc

@@ -292,7 +292,7 @@ TEST_F(BackdropFilterLayerTest, OpacityInheritance) {
   parent->Add(layer);
   clip->Add(parent);
 
-  clip->Preroll(preroll_context(), SkMatrix::I());
+  clip->Preroll(display_list_preroll_context(), SkMatrix::I());
 
   clip->Paint(display_list_paint_context());
 

flow/layers/checkerboard_layertree_unittests.cc

@@ -18,7 +18,7 @@ namespace testing {
 using CheckerBoardLayerTest = LayerTest;
 
 #ifndef NDEBUG
-TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerNotCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerNotCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect cull_bounds = SkRect::MakeXYWH(0.0, 0.0, 2.0, 4.0);
   const SkRect child_bounds = SkRect::MakeXYWH(2.5, 5.0, 4.5, 4.0);
@@ -68,7 +68,7 @@ TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerNotCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect cull_bounds = SkRect::MakeXYWH(0.0, 0.0, 2.0, 4.0);
   const SkRect child_bounds = SkRect::MakeXYWH(2.5, 5.0, 4.5, 4.0);
@@ -100,7 +100,7 @@ TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerCheckBoard) {
   EXPECT_EQ(mock_layer->parent_mutators(),
             std::vector({Mutator(layer_bounds)}));
 
-  layer->Paint(check_board_context());
+  layer->Paint(checkerboard_context());
 
   EXPECT_NE(
       mock_canvas().draw_calls(),
@@ -118,7 +118,7 @@ TEST_F(CheckerBoardLayerTest, ClipRectSaveLayerCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerNotCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerNotCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect child_bounds = SkRect::MakeXYWH(1.0, 2.0, 2.0, 2.0);
   const SkRect layer_bounds = SkRect::MakeXYWH(0.5, 1.0, 5.0, 6.0);
@@ -159,7 +159,7 @@ TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerNotCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect child_bounds = SkRect::MakeXYWH(1.0, 2.0, 2.0, 2.0);
   const SkRect layer_bounds = SkRect::MakeXYWH(0.5, 1.0, 5.0, 6.0);
@@ -183,7 +183,7 @@ TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerCheckBoard) {
   EXPECT_EQ(mock_layer->parent_matrix(), initial_matrix);
   EXPECT_EQ(mock_layer->parent_mutators(), std::vector({Mutator(layer_path)}));
 
-  layer->Paint(check_board_context());
+  layer->Paint(checkerboard_context());
   EXPECT_NE(
       mock_canvas().draw_calls(),
       std::vector(
@@ -200,7 +200,7 @@ TEST_F(CheckerBoardLayerTest, ClipPathSaveLayerCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerNotCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerNotCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect child_bounds = SkRect::MakeXYWH(1.0, 2.0, 2.0, 2.0);
   const SkRect layer_bounds = SkRect::MakeXYWH(0.5, 1.0, 5.0, 6.0);
@@ -241,7 +241,7 @@ TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerNotCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerCheckBoard) {
+TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerCheckerBoard) {
   const SkMatrix initial_matrix = SkMatrix::Translate(0.5f, 1.0f);
   const SkRect child_bounds = SkRect::MakeXYWH(1.0, 2.0, 2.0, 2.0);
   const SkRect layer_bounds = SkRect::MakeXYWH(0.5, 1.0, 5.0, 6.0);
@@ -265,7 +265,7 @@ TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerCheckBoard) {
   EXPECT_EQ(mock_layer->parent_matrix(), initial_matrix);
   EXPECT_EQ(mock_layer->parent_mutators(), std::vector({Mutator(layer_rrect)}));
 
-  layer->Paint(check_board_context());
+  layer->Paint(checkerboard_context());
   EXPECT_NE(
       mock_canvas().draw_calls(),
       std::vector(
@@ -282,7 +282,7 @@ TEST_F(CheckerBoardLayerTest, ClipRRectSaveLayerCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerNotCheckBoard) {
+TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerNotCheckerBoard) {
   constexpr float initial_elevation = 20.0f;
   SkPath layer_path;
   layer_path.addRect(0, 0, 8, 8).close();
@@ -303,7 +303,6 @@ TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerNotCheckBoard) {
   const SkPaint clip_paint;
   SkPaint layer_paint;
   layer_paint.setColor(SK_ColorGREEN);
-  layer_paint.setAntiAlias(true);
   layer->Paint(paint_context());
   EXPECT_EQ(
       mock_canvas().draw_calls(),
@@ -321,7 +320,7 @@ TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerNotCheckBoard) {
            MockCanvas::DrawCall{1, MockCanvas::RestoreData{0}}}));
 }
 
-TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerCheckBoard) {
+TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerCheckerBoard) {
   constexpr float initial_elevation = 20.0f;
   SkPath layer_path;
   layer_path.addRect(0, 0, 8, 8).close();
@@ -342,8 +341,7 @@ TEST_F(CheckerBoardLayerTest, PhysicalSaveLayerCheckBoard) {
   const SkPaint clip_paint;
   SkPaint layer_paint;
   layer_paint.setColor(SK_ColorGREEN);
-  layer_paint.setAntiAlias(true);
-  layer->Paint(check_board_context());
+  layer->Paint(checkerboard_context());
   EXPECT_NE(
       mock_canvas().draw_calls(),
       std::vector(

flow/layers/clip_path_layer.cc

@@ -28,8 +28,9 @@ void ClipPathLayer::OnMutatorsStackPushClipShape(
   mutators_stack.PushClipPath(clip_shape());
 }
 
-void ClipPathLayer::OnCanvasClipShape(SkCanvas* canvas) const {
-  canvas->clipPath(clip_shape(), clip_behavior() != Clip::hardEdge);
+void ClipPathLayer::OnStackClipShape(
+    LayerStateStack::MutatorContext& mutator) const {
+  mutator.clipPath(clip_shape(), clip_behavior() != Clip::hardEdge);
 }
 
 }  // namespace flutter

flow/layers/clip_path_layer.h

@@ -23,7 +23,8 @@ class ClipPathLayer : public ClipShapeLayer<SkPath> {
 
   void OnMutatorsStackPushClipShape(MutatorsStack& mutators_stack) override;
 
-  void OnCanvasClipShape(SkCanvas* canvas) const override;
+  void OnStackClipShape(
+      LayerStateStack::MutatorContext& mutator) const override;
 
  private:
   FML_DISALLOW_COPY_AND_ASSIGN(ClipPathLayer);