[DisplayList] DlPath object provides auto-conversion from Skia to Impeller (#55055)

Switch from using the clumsy manual CacheablePath object to a more automatic DlPath object for holding paths in DisplayLists and dispatching them to either Skia or Impeller with auto-conversion.

For now DlPath is just a wrapper around SkPath with an auto-generating Impeller Path object which is very similar in design from what was done with the CacheablePath object except that it manages the caching of the Impeller path internally without extra burden on Impeller or Skia. There is also no need to communicate with the Dispatch method as to which type of path you prefer, they're all "auto-converting" DlPath objects now.

For now, ui.Path still generates an SkPath and so we wrap it when we record it into a DisplayList, just like the former CacheablePath mechanism. It will be a simple conversion to create the DlPath wrapper in ui.Path, though, so as to maintain the cached Impeller paths across frames even if the DisplayList itself is not preserved.

Eventually DlPath will take on more of a role of hiding the construction and internal representation of the paths so that we could be using SkPath, impeller::Path, or some other internal storage. For now, SkPath will likely remain primary storage for a while so that we can deal with PathOps.

Author: flar

ci/licenses_golden/excluded_files

@@ -41,6 +41,7 @@
 ../../../flutter/display_list/effects/dl_image_filter_unittests.cc
 ../../../flutter/display_list/effects/dl_mask_filter_unittests.cc
 ../../../flutter/display_list/geometry/dl_geometry_types_unittests.cc
+../../../flutter/display_list/geometry/dl_path_unittests.cc
 ../../../flutter/display_list/geometry/dl_region_unittests.cc
 ../../../flutter/display_list/geometry/dl_rtree_unittests.cc
 ../../../flutter/display_list/skia/dl_sk_conversions_unittests.cc

ci/licenses_golden/licenses_flutter

@@ -42345,6 +42345,8 @@ ORIGIN: ../../../flutter/display_list/effects/dl_mask_filter.h + ../../../flutte
 ORIGIN: ../../../flutter/display_list/effects/dl_runtime_effect.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/effects/dl_runtime_effect.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/geometry/dl_geometry_types.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/display_list/geometry/dl_path.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/display_list/geometry/dl_path.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/geometry/dl_region.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/geometry/dl_region.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/display_list/geometry/dl_rtree.cc + ../../../flutter/LICENSE
@@ -45240,6 +45242,8 @@ FILE: ../../../flutter/display_list/effects/dl_mask_filter.h
 FILE: ../../../flutter/display_list/effects/dl_runtime_effect.cc
 FILE: ../../../flutter/display_list/effects/dl_runtime_effect.h
 FILE: ../../../flutter/display_list/geometry/dl_geometry_types.h
+FILE: ../../../flutter/display_list/geometry/dl_path.cc
+FILE: ../../../flutter/display_list/geometry/dl_path.h
 FILE: ../../../flutter/display_list/geometry/dl_region.cc
 FILE: ../../../flutter/display_list/geometry/dl_region.h
 FILE: ../../../flutter/display_list/geometry/dl_rtree.cc

display_list/BUILD.gn

@@ -60,6 +60,8 @@ source_set("display_list") {
     "effects/dl_runtime_effect.cc",
     "effects/dl_runtime_effect.h",
     "geometry/dl_geometry_types.h",
+    "geometry/dl_path.cc",
+    "geometry/dl_path.h",
     "geometry/dl_region.cc",
     "geometry/dl_region.h",
     "geometry/dl_rtree.cc",
@@ -119,6 +121,7 @@ if (enable_unittests) {
       "effects/dl_image_filter_unittests.cc",
       "effects/dl_mask_filter_unittests.cc",
       "geometry/dl_geometry_types_unittests.cc",
+      "geometry/dl_path_unittests.cc",
       "geometry/dl_region_unittests.cc",
       "geometry/dl_rtree_unittests.cc",
       "skia/dl_sk_conversions_unittests.cc",

display_list/benchmarking/dl_complexity_gl.cc

@@ -332,7 +332,7 @@ void DisplayListGLComplexityCalculator::GLHelper::drawDRRect(
   AccumulateComplexity(complexity);
 }
 
-void DisplayListGLComplexityCalculator::GLHelper::drawPath(const SkPath& path) {
+void DisplayListGLComplexityCalculator::GLHelper::drawPath(const DlPath& path) {
   if (IsComplex()) {
     return;
   }
@@ -655,7 +655,7 @@ void DisplayListGLComplexityCalculator::GLHelper::drawTextFrame(
     DlScalar y) {}
 
 void DisplayListGLComplexityCalculator::GLHelper::drawShadow(
-    const SkPath& path,
+    const DlPath& path,
     const DlColor color,
     const DlScalar elevation,
     bool transparent_occluder,

display_list/benchmarking/dl_complexity_gl.h

@@ -49,7 +49,7 @@ class DisplayListGLComplexityCalculator
     void drawCircle(const DlPoint& center, DlScalar radius) override;
     void drawRRect(const SkRRect& rrect) override;
     void drawDRRect(const SkRRect& outer, const SkRRect& inner) override;
-    void drawPath(const SkPath& path) override;
+    void drawPath(const DlPath& path) override;
     void drawArc(const DlRect& oval_bounds,
                  DlScalar start_degrees,
                  DlScalar sweep_degrees,
@@ -76,7 +76,7 @@ class DisplayListGLComplexityCalculator
     void drawTextFrame(const std::shared_ptr<impeller::TextFrame>& text_frame,
                        DlScalar x,
                        DlScalar y) override;
-    void drawShadow(const SkPath& path,
+    void drawShadow(const DlPath& path,
                     const DlColor color,
                     const DlScalar elevation,
                     bool transparent_occluder,

display_list/benchmarking/dl_complexity_helper.h

@@ -214,11 +214,12 @@ class ComplexityCalculatorHelper
   inline unsigned int Ceiling() { return ceiling_; }
   inline unsigned int CurrentComplexityScore() { return complexity_score_; }
 
-  unsigned int CalculatePathComplexity(const SkPath& path,
+  unsigned int CalculatePathComplexity(const DlPath& dl_path,
                                        unsigned int line_verb_cost,
                                        unsigned int quad_verb_cost,
                                        unsigned int conic_verb_cost,
                                        unsigned int cubic_verb_cost) {
+    const SkPath& path = dl_path.GetSkPath();
     int verb_count = path.countVerbs();
     std::vector<uint8_t> verbs(verb_count);
     path.getVerbs(verbs.data(), verbs.size());

display_list/benchmarking/dl_complexity_metal.cc

@@ -329,7 +329,7 @@ void DisplayListMetalComplexityCalculator::MetalHelper::drawDRRect(
 }
 
 void DisplayListMetalComplexityCalculator::MetalHelper::drawPath(
-    const SkPath& path) {
+    const DlPath& path) {
   if (IsComplex()) {
     return;
   }
@@ -599,7 +599,7 @@ void DisplayListMetalComplexityCalculator::MetalHelper::drawTextFrame(
     DlScalar y) {}
 
 void DisplayListMetalComplexityCalculator::MetalHelper::drawShadow(
-    const SkPath& path,
+    const DlPath& path,
     const DlColor color,
     const DlScalar elevation,
     bool transparent_occluder,

display_list/benchmarking/dl_complexity_metal.h

@@ -49,7 +49,7 @@ class DisplayListMetalComplexityCalculator
     void drawCircle(const DlPoint& center, DlScalar radius) override;
     void drawRRect(const SkRRect& rrect) override;
     void drawDRRect(const SkRRect& outer, const SkRRect& inner) override;
-    void drawPath(const SkPath& path) override;
+    void drawPath(const DlPath& path) override;
     void drawArc(const DlRect& oval_bounds,
                  DlScalar start_degrees,
                  DlScalar sweep_degrees,
@@ -76,7 +76,7 @@ class DisplayListMetalComplexityCalculator
     void drawTextFrame(const std::shared_ptr<impeller::TextFrame>& text_frame,
                        DlScalar x,
                        DlScalar y) override;
-    void drawShadow(const SkPath& path,
+    void drawShadow(const DlPath& path,
                     const DlColor color,
                     const DlScalar elevation,
                     bool transparent_occluder,

display_list/display_list_unittests.cc

@@ -3618,98 +3618,6 @@ TEST_F(DisplayListTest, NopOperationsOmittedFromRecords) {
             });
 }
 
-TEST_F(DisplayListTest, ImpellerPathPreferenceIsHonored) {
-  class Tester : public virtual DlOpReceiver,
-                 public IgnoreClipDispatchHelper,
-                 public IgnoreDrawDispatchHelper,
-                 public IgnoreAttributeDispatchHelper,
-                 public IgnoreTransformDispatchHelper {
-   public:
-    explicit Tester(bool prefer_impeller_paths)
-        : prefer_impeller_paths_(prefer_impeller_paths) {}
-
-    bool PrefersImpellerPaths() const override {
-      return prefer_impeller_paths_;
-    }
-
-    void drawPath(const SkPath& path) override { skia_draw_path_calls_++; }
-
-    void drawPath(const CacheablePath& cache) override {
-      impeller_draw_path_calls_++;
-    }
-
-    void clipPath(const SkPath& path, ClipOp op, bool is_aa) override {
-      skia_clip_path_calls_++;
-    }
-
-    void clipPath(const CacheablePath& cache, ClipOp op, bool is_aa) override {
-      impeller_clip_path_calls_++;
-    }
-
-    virtual void drawShadow(const SkPath& sk_path,
-                            const DlColor color,
-                            const SkScalar elevation,
-                            bool transparent_occluder,
-                            SkScalar dpr) override {
-      skia_draw_shadow_calls_++;
-    }
-
-    virtual void drawShadow(const CacheablePath& cache,
-                            const DlColor color,
-                            const SkScalar elevation,
-                            bool transparent_occluder,
-                            SkScalar dpr) override {
-      impeller_draw_shadow_calls_++;
-    }
-
-    int skia_draw_path_calls() const { return skia_draw_path_calls_; }
-    int skia_clip_path_calls() const { return skia_draw_path_calls_; }
-    int skia_draw_shadow_calls() const { return skia_draw_path_calls_; }
-    int impeller_draw_path_calls() const { return impeller_draw_path_calls_; }
-    int impeller_clip_path_calls() const { return impeller_draw_path_calls_; }
-    int impeller_draw_shadow_calls() const { return impeller_draw_path_calls_; }
-
-   private:
-    const bool prefer_impeller_paths_;
-    int skia_draw_path_calls_ = 0;
-    int skia_clip_path_calls_ = 0;
-    int skia_draw_shadow_calls_ = 0;
-    int impeller_draw_path_calls_ = 0;
-    int impeller_clip_path_calls_ = 0;
-    int impeller_draw_shadow_calls_ = 0;
-  };
-
-  DisplayListBuilder builder;
-  builder.DrawPath(SkPath::Rect(SkRect::MakeLTRB(0, 0, 100, 100)), DlPaint());
-  builder.ClipPath(SkPath::Rect(SkRect::MakeLTRB(0, 0, 100, 100)),
-                   ClipOp::kIntersect, true);
-  builder.DrawShadow(SkPath::Rect(SkRect::MakeLTRB(20, 20, 80, 80)),
-                     DlColor::kBlue(), 1.0f, true, 1.0f);
-  auto display_list = builder.Build();
-
-  {
-    Tester skia_tester(false);
-    display_list->Dispatch(skia_tester);
-    EXPECT_EQ(skia_tester.skia_draw_path_calls(), 1);
-    EXPECT_EQ(skia_tester.skia_clip_path_calls(), 1);
-    EXPECT_EQ(skia_tester.skia_draw_shadow_calls(), 1);
-    EXPECT_EQ(skia_tester.impeller_draw_path_calls(), 0);
-    EXPECT_EQ(skia_tester.impeller_clip_path_calls(), 0);
-    EXPECT_EQ(skia_tester.impeller_draw_shadow_calls(), 0);
-  }
-
-  {
-    Tester impeller_tester(true);
-    display_list->Dispatch(impeller_tester);
-    EXPECT_EQ(impeller_tester.skia_draw_path_calls(), 0);
-    EXPECT_EQ(impeller_tester.skia_clip_path_calls(), 0);
-    EXPECT_EQ(impeller_tester.skia_draw_shadow_calls(), 0);
-    EXPECT_EQ(impeller_tester.impeller_draw_path_calls(), 1);
-    EXPECT_EQ(impeller_tester.impeller_clip_path_calls(), 1);
-    EXPECT_EQ(impeller_tester.impeller_draw_shadow_calls(), 1);
-  }
-}
-
 class SaveLayerBoundsExpector : public virtual DlOpReceiver,
                                 public IgnoreAttributeDispatchHelper,
                                 public IgnoreClipDispatchHelper,
@@ -4616,7 +4524,7 @@ TEST_F(DisplayListTest, DrawDisplayListForwardsBackdropFlag) {
 #define CLIP_EXPECTOR(name) ClipExpector name(__FILE__, __LINE__)
 
 struct ClipExpectation {
-  std::variant<DlRect, SkRRect, SkPath> shape;
+  std::variant<DlRect, SkRRect, DlPath> shape;
   bool is_oval;
   ClipOp clip_op;
   bool is_aa;
@@ -4628,7 +4536,7 @@ struct ClipExpectation {
       case 1:
         return "SkRRect";
       case 2:
-        return "SkPath";
+        return "DlPath";
       default:
         return "Unknown";
     }
@@ -4648,7 +4556,7 @@ ::std::ostream& operator<<(::std::ostream& os, const ClipExpectation& expect) {
       os << std::get<SkRRect>(expect.shape);
       break;
     case 2:
-      os << std::get<SkPath>(expect.shape);
+      os << std::get<DlPath>(expect.shape).GetSkPath();
       break;
     case 3:
       os << "Unknown";
@@ -4713,7 +4621,7 @@ class ClipExpector : public virtual DlOpReceiver,
     return *this;
   }
 
-  ClipExpector& addExpectation(const SkPath& path,
+  ClipExpector& addExpectation(const DlPath& path,
                                ClipOp clip_op = ClipOp::kIntersect,
                                bool is_aa = false) {
     clip_expectations_.push_back({
@@ -4725,6 +4633,12 @@ class ClipExpector : public virtual DlOpReceiver,
     return *this;
   }
 
+  ClipExpector& addExpectation(const SkPath& path,
+                               ClipOp clip_op = ClipOp::kIntersect,
+                               bool is_aa = false) {
+    return addExpectation(DlPath(path), clip_op, is_aa);
+  }
+
   void clipRect(const DlRect& rect,
                 DlCanvas::ClipOp clip_op,
                 bool is_aa) override {
@@ -4740,7 +4654,7 @@ class ClipExpector : public virtual DlOpReceiver,
                  bool is_aa) override {
     check(rrect, clip_op, is_aa);
   }
-  void clipPath(const SkPath& path,
+  void clipPath(const DlPath& path,
                 DlCanvas::ClipOp clip_op,
                 bool is_aa) override {
     check(path, clip_op, is_aa);

display_list/dl_builder.cc

@@ -1044,30 +1044,30 @@ void DisplayListBuilder::ClipRRect(const SkRRect& rrect,
       break;
   }
 }
-void DisplayListBuilder::ClipPath(const SkPath& path,
+void DisplayListBuilder::ClipPath(const DlPath& path,
                                   ClipOp clip_op,
                                   bool is_aa) {
   if (current_info().is_nop) {
     return;
   }
-  if (!path.isInverseFillType()) {
+  if (!path.IsInverseFillType()) {
     SkRect rect;
-    if (path.isRect(&rect)) {
+    if (path.IsSkRect(&rect)) {
       ClipRect(rect, clip_op, is_aa);
       return;
     }
-    if (path.isOval(&rect)) {
+    if (path.IsSkOval(&rect)) {
       ClipOval(rect, clip_op, is_aa);
       return;
     }
     SkRRect rrect;
-    if (path.isRRect(&rrect)) {
+    if (path.IsSkRRect(&rrect)) {
       ClipRRect(rrect, clip_op, is_aa);
       return;
     }
   }
-  global_state().clipPath(path, clip_op, is_aa);
-  layer_local_state().clipPath(path, clip_op, is_aa);
+  global_state().clipPath(path.GetSkPath(), clip_op, is_aa);
+  layer_local_state().clipPath(path.GetSkPath(), clip_op, is_aa);
   if (global_state().is_cull_rect_empty() ||
       layer_local_state().is_cull_rect_empty()) {
     current_info().is_nop = true;
@@ -1234,13 +1234,14 @@ void DisplayListBuilder::DrawDRRect(const SkRRect& outer,
   SetAttributesFromPaint(paint, DisplayListOpFlags::kDrawDRRectFlags);
   drawDRRect(outer, inner);
 }
-void DisplayListBuilder::drawPath(const SkPath& path) {
+void DisplayListBuilder::drawPath(const DlPath& path) {
   DisplayListAttributeFlags flags = kDrawPathFlags;
   OpResult result = PaintResult(current_, flags);
   if (result != OpResult::kNoEffect) {
-    bool is_visible = path.isInverseFillType()
-                          ? AccumulateUnbounded()
-                          : AccumulateOpBounds(path.getBounds(), flags);
+    bool is_visible =
+        path.IsInverseFillType()
+            ? AccumulateUnbounded()
+            : AccumulateOpBounds(ToSkRect(path.GetBounds()), flags);
     if (is_visible) {
       Push<DrawPathOp>(0, path);
       CheckLayerOpacityHairlineCompatibility();
@@ -1249,6 +1250,11 @@ void DisplayListBuilder::drawPath(const SkPath& path) {
   }
 }
 void DisplayListBuilder::DrawPath(const SkPath& path, const DlPaint& paint) {
+  SetAttributesFromPaint(paint, DisplayListOpFlags::kDrawPathFlags);
+  DlPath dl_path(path);
+  drawPath(dl_path);
+}
+void DisplayListBuilder::DrawPath(const DlPath& path, const DlPaint& paint) {
   SetAttributesFromPaint(paint, DisplayListOpFlags::kDrawPathFlags);
   drawPath(path);
 }
@@ -1731,15 +1737,15 @@ void DisplayListBuilder::DrawTextFrame(
   drawTextFrame(text_frame, x, y);
 }
 
-void DisplayListBuilder::DrawShadow(const SkPath& path,
+void DisplayListBuilder::DrawShadow(const DlPath& path,
                                     const DlColor color,
                                     const DlScalar elevation,
                                     bool transparent_occluder,
                                     DlScalar dpr) {
   OpResult result = PaintResult(DlPaint(color));
   if (result != OpResult::kNoEffect) {
-    SkRect shadow_bounds =
-        DlCanvas::ComputeShadowBounds(path, elevation, dpr, GetTransform());
+    SkRect shadow_bounds = DlCanvas::ComputeShadowBounds(
+        path.GetSkPath(), elevation, dpr, GetTransform());
     if (AccumulateOpBounds(shadow_bounds, kDrawShadowFlags)) {
       transparent_occluder  //
           ? Push<DrawShadowTransparentOccluderOp>(0, path, color, elevation,