flutter · auto-submit · Jun 9, 2025 · Jun 2, 2025 · Jun 2, 2025 · Jun 2, 2025
diff --git a/engine/src/flutter/ci/licenses_golden/licenses_flutter b/engine/src/flutter/ci/licenses_golden/licenses_flutter
@@ -51471,6 +51471,8 @@ ORIGIN: ../../../flutter/impeller/geometry/color.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/color.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/constants.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/constants.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/geometry/dashed_line_path_source.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/geometry/dashed_line_path_source.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/geometry_asserts.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/geometry_benchmarks.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/geometry/gradient.cc + ../../../flutter/LICENSE
@@ -54488,6 +54490,8 @@ FILE: ../../../flutter/impeller/geometry/color.cc
 FILE: ../../../flutter/impeller/geometry/color.h
 FILE: ../../../flutter/impeller/geometry/constants.cc
 FILE: ../../../flutter/impeller/geometry/constants.h
+FILE: ../../../flutter/impeller/geometry/dashed_line_path_source.cc
+FILE: ../../../flutter/impeller/geometry/dashed_line_path_source.h
 FILE: ../../../flutter/impeller/geometry/geometry_asserts.h
 FILE: ../../../flutter/impeller/geometry/geometry_benchmarks.cc
 FILE: ../../../flutter/impeller/geometry/gradient.cc

diff --git a/engine/src/flutter/impeller/display_list/canvas.cc b/engine/src/flutter/impeller/display_list/canvas.cc
@@ -603,6 +603,32 @@ void Canvas::DrawLine(const Point& p0,
   }
 }
 
+void Canvas::DrawDashedLine(const Point& p0,
+                            const Point& p1,
+                            Scalar on_length,
+                            Scalar off_length,
+                            const Paint& paint) {
+  // Reasons to defer to regular DrawLine:
+  // - performance for degenerate and "regular line" cases
+  // - length is non-positive - DrawLine will draw appropriate "dot"
+  // - off_length is non-positive - no gaps, DrawLine will draw it solid
+  // - on_length is negative - invalid dashing
+  //
+  // Note that a 0 length "on" dash will draw "dot"s every "off" distance
+  // apart so we proceed with the dashing process in that case.
+  Scalar length = p0.GetDistance(p1);
+  if (length > 0.0f && on_length >= 0.0f && off_length > 0.0f) {
+    Entity entity;
+    entity.SetTransform(GetCurrentTransform());
+    entity.SetBlendMode(paint.blend_mode);
+
+    StrokeDashedLineGeometry geom(p0, p1, on_length, off_length, paint.stroke);
+    AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
+  } else {
+    DrawLine(p0, p1, paint);
+  }
+}
+
 void Canvas::DrawRect(const Rect& rect, const Paint& paint) {
   if (AttemptDrawBlurredRRect(rect, {}, paint)) {
     return;

diff --git a/engine/src/flutter/impeller/display_list/canvas.h b/engine/src/flutter/impeller/display_list/canvas.h
@@ -199,6 +199,12 @@ class Canvas {
                 const Paint& paint,
                 bool reuse_depth = false);
 
+  void DrawDashedLine(const Point& p0,
+                      const Point& p1,
+                      Scalar on_length,
+                      Scalar off_length,
+                      const Paint& paint);
+
   void DrawRect(const Rect& rect, const Paint& paint);
 
   void DrawOval(const Rect& rect, const Paint& paint);

diff --git a/engine/src/flutter/impeller/display_list/dl_dispatcher.cc b/engine/src/flutter/impeller/display_list/dl_dispatcher.cc
@@ -12,7 +12,6 @@
 
 #include "display_list/dl_sampling_options.h"
 #include "display_list/effects/dl_image_filter.h"
-#include "display_list/geometry/dl_path_builder.h"
 #include "flutter/fml/logging.h"
 #include "fml/closure.h"
 #include "impeller/core/formats.h"
@@ -547,46 +546,14 @@ void DlDispatcherBase::drawLine(const DlPoint& p0, const DlPoint& p1) {
   GetCanvas().DrawLine(p0, p1, paint_);
 }
 
+// |flutter::DlOpReceiver|
 void DlDispatcherBase::drawDashedLine(const DlPoint& p0,
                                       const DlPoint& p1,
                                       DlScalar on_length,
                                       DlScalar off_length) {
   AUTO_DEPTH_WATCHER(1u);
 
-  Scalar length = p0.GetDistance(p1);
-  // Reasons to defer to regular DrawLine:
-  //   length is non-positive - drawLine will draw appropriate "dot"
-  //   off_length is non-positive - no gaps, drawLine will draw it solid
-  //   on_length is negative - invalid dashing
-  // Note that a 0 length "on" dash will draw "dot"s every "off" distance
-  // apart
-  if (length > 0.0f && on_length >= 0.0f && off_length > 0.0f) {
-    Point delta = (p1 - p0) / length;  // length > 0 already tested
-    flutter::DlPathBuilder builder;
-
-    Scalar consumed = 0.0f;
-    while (consumed < length) {
-      builder.MoveTo(p0 + delta * consumed);
-
-      Scalar dash_end = consumed + on_length;
-      if (dash_end < length) {
-        builder.LineTo(p0 + delta * dash_end);
-      } else {
-        builder.LineTo(p1);
-        // Should happen anyway due to the math, but let's make it explicit
-        // in case of bit errors. We're done with this line.
-        break;
-      }
-
-      consumed = dash_end + off_length;
-    }
-
-    Paint stroke_paint = paint_;
-    stroke_paint.style = Paint::Style::kStroke;
-    GetCanvas().DrawPath(builder.TakePath(), stroke_paint);
-  } else {
-    drawLine(p0, p1);
-  }
+  GetCanvas().DrawDashedLine(p0, p1, on_length, off_length, paint_);
 }
 
 // |flutter::DlOpReceiver|

diff --git a/engine/src/flutter/impeller/entity/geometry/stroke_path_geometry.cc b/engine/src/flutter/impeller/entity/geometry/stroke_path_geometry.cc
@@ -846,4 +846,17 @@ const PathSource& StrokeDiffRoundRectGeometry::GetSource() const {
   return source_;
 }
 
+StrokeDashedLineGeometry::StrokeDashedLineGeometry(
+    Point p0,
+    Point p1,
+    Scalar on_length,
+    Scalar off_length,
+    const StrokeParameters& parameters)
+    : StrokePathSourceGeometry(parameters),
+      source_(p0, p1, on_length, off_length) {}
+
+const PathSource& StrokeDashedLineGeometry::GetSource() const {
+  return source_;
+}
+
 }  // namespace impeller
diff --git a/engine/src/flutter/impeller/entity/geometry/stroke_path_geometry.h b/engine/src/flutter/impeller/entity/geometry/stroke_path_geometry.h
@@ -6,6 +6,7 @@
 #define FLUTTER_IMPELLER_ENTITY_GEOMETRY_STROKE_PATH_GEOMETRY_H_
 
 #include "impeller/entity/geometry/geometry.h"
+#include "impeller/geometry/dashed_line_path_source.h"
 #include "impeller/geometry/matrix.h"
 #include "impeller/geometry/path_source.h"
 #include "impeller/geometry/stroke_parameters.h"
@@ -126,6 +127,25 @@ class StrokeDiffRoundRectGeometry final : public StrokePathSourceGeometry {
   const DiffRoundRectPathSource source_;
 };
 
+/// @brief A Geometry that produces fillable vertices representing the
+///        stroked outline of a |DlPath| object using the
+///        |StrokePathSourceGeometry| base class and a |DlPath| object
+///        to perform path iteration.
+class StrokeDashedLineGeometry final : public StrokePathSourceGeometry {
+ public:
+  StrokeDashedLineGeometry(Point p0,
+                           Point p1,
+                           Scalar on_length,
+                           Scalar off_length,
+                           const StrokeParameters& parameters);
+
+ protected:
+  const PathSource& GetSource() const override;
+
+ private:
+  const DashedLinePathSource source_;
+};
+
 }  // namespace impeller
 
 #endif  // FLUTTER_IMPELLER_ENTITY_GEOMETRY_STROKE_PATH_GEOMETRY_H_
diff --git a/engine/src/flutter/impeller/geometry/BUILD.gn b/engine/src/flutter/impeller/geometry/BUILD.gn
@@ -10,6 +10,8 @@ impeller_component("geometry") {
     "color.h",
     "constants.cc",
     "constants.h",
+    "dashed_line_path_source.cc",
+    "dashed_line_path_source.h",
     "gradient.cc",
     "gradient.h",
     "half.h",

diff --git a/engine/src/flutter/impeller/geometry/dashed_line_path_source.cc b/engine/src/flutter/impeller/geometry/dashed_line_path_source.cc
@@ -0,0 +1,68 @@
+// Copyright 2013 The Flutter 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 "impeller/geometry/dashed_line_path_source.h"
+
+namespace impeller {
+
+DashedLinePathSource::DashedLinePathSource(Point p0,
+                                           Point p1,
+                                           Scalar on_length,
+                                           Scalar off_length)
+    : p0_(p0), p1_(p1), on_length_(on_length), off_length_(off_length) {}
+
+DashedLinePathSource::~DashedLinePathSource() = default;
+
+FillType DashedLinePathSource::GetFillType() const {
+  return FillType::kNonZero;
+}
+
+Rect DashedLinePathSource::GetBounds() const {
+  return Rect::MakeLTRB(p0_.x, p0_.y, p1_.x, p1_.y).GetPositive();
+}
+
+bool DashedLinePathSource::IsConvex() const {
+  return false;
+}
+
+void DashedLinePathSource::Dispatch(PathReceiver& receiver) const {
+  // Exceptional conditions:
+  // - length is non-positive - result will draw only a "dot"
+  // - off_length is non-positive - no gaps, result is a solid line
+  // - on_length is negative - invalid dashing
+  // Note that a 0 length "on" dash will draw "dot"s every "off" distance
+  // apart so we still generate the dashing for that case.
+  //
+  // Note that Canvas will detect these conditions and use its own DrawLine
+  // method directly for performance reasons for a single line, but in case
+  // someone uses this PathSource with these exceptional cases, we degenerate
+  // gracefully into a single line segment path description below.
+  Scalar length = p0_.GetDistance(p1_);
+  if (length > 0.0f && on_length_ >= 0.0f && off_length_ > 0.0f) {
+    Point delta = (p1_ - p0_) / length;  // length > 0 already verified
+
+    Scalar consumed = 0.0f;
+    while (consumed < length) {
+      receiver.MoveTo(p0_ + delta * consumed, false);
+
+      Scalar dash_end = consumed + on_length_;
+      if (dash_end < length) {
+        receiver.LineTo(p0_ + delta * dash_end);
+      } else {
+        receiver.LineTo(p1_);
+        // Should happen anyway due to the math, but let's make it explicit
+        // in case of bit errors. We're done with this line.
+        break;
+      }
+
+      consumed = dash_end + off_length_;
+    }
+  } else {
+    receiver.MoveTo(p0_, false);
+    receiver.LineTo(p1_);
+  }
+  receiver.PathEnd();
+}
+
+}  // namespace impeller
diff --git a/engine/src/flutter/impeller/geometry/dashed_line_path_source.h b/engine/src/flutter/impeller/geometry/dashed_line_path_source.h
@@ -0,0 +1,42 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_IMPELLER_GEOMETRY_DASHED_LINE_PATH_SOURCE_H_
+#define FLUTTER_IMPELLER_GEOMETRY_DASHED_LINE_PATH_SOURCE_H_
+
+#include "flutter/impeller/geometry/path_source.h"
+#include "flutter/impeller/geometry/point.h"
+#include "flutter/impeller/geometry/scalar.h"
+
+namespace impeller {
+
+/// @brief A PathSource that generates the various segments of a dashed line.
+class DashedLinePathSource : public PathSource {
+ public:
+  DashedLinePathSource(Point p0, Point p1, Scalar on_length, Scalar off_length);
+
+  ~DashedLinePathSource();
+
+  // |PathSource|
+  FillType GetFillType() const override;
+
+  // |PathSource|
+  Rect GetBounds() const override;
+
+  // |PathSource|
+  bool IsConvex() const override;
+
+  // |PathSource|
+  void Dispatch(PathReceiver& receiver) const override;
+
+ private:
+  const Point p0_;
+  const Point p1_;
+  const Scalar on_length_;
+  const Scalar off_length_;
+};
+
+}  // namespace impeller
+
+#endif  // FLUTTER_IMPELLER_GEOMETRY_DASHED_LINE_PATH_SOURCE_H_