Convert RRect.scaleRadii to public method (#9452)

* convert RRect.scaleRadii to public method

* Add scaleRadii tests

lib/stub_ui/lib/src/ui/geometry.dart

@@ -1412,12 +1412,16 @@ class RRect {
     return min;
   }
 
-  // Scales all radii so that on each side their sum will not pass the size of
-  // the width/height.
-  //
-  // Inspired from:
-  //   https://github.com/google/skia/blob/master/src/core/SkRRect.cpp#L164
-  RRect _scaleRadii() {
+  /// Scales all radii so that on each side their sum will not exceed the size
+  /// of the width/height.
+  ///
+  /// Skia already handles RRects with radii that are too large in this way.
+  /// Therefore, this method is only needed for RRect use cases that require
+  /// the appropriately scaled radii values.
+  ///
+  /// See the [Skia scaling implementation](https://github.com/google/skia/blob/master/src/core/SkRRect.cpp)
+  /// for more details.
+  RRect scaleRadii() {
     double scale = 1.0;
     scale = _getMin(scale, blRadiusY, tlRadiusY, height);
     scale = _getMin(scale, tlRadiusX, trRadiusX, width);
@@ -1470,7 +1474,7 @@ class RRect {
         point.dy < top ||
         point.dy >= bottom) return false; // outside bounding box
 
-    final RRect scaled = _scaleRadii();
+    final RRect scaled = scaleRadii();
 
     double x;
     double y;

lib/ui/geometry.dart

@@ -1416,12 +1416,16 @@ class RRect {
     return min;
   }
 
-  // Scales all radii so that on each side their sum will not pass the size of
-  // the width/height.
-  //
-  // Inspired from:
-  //   https://github.com/google/skia/blob/master/src/core/SkRRect.cpp#L164
-  RRect _scaleRadii() {
+  /// Scales all radii so that on each side their sum will not exceed the size
+  /// of the width/height.
+  ///
+  /// Skia already handles RRects with radii that are too large in this way.
+  /// Therefore, this method is only needed for RRect use cases that require
+  /// the appropriately scaled radii values.
+  ///
+  /// See the [Skia scaling implementation](https://github.com/google/skia/blob/master/src/core/SkRRect.cpp)
+  /// for more details.
+  RRect scaleRadii() {
     double scale = 1.0;
     scale = _getMin(scale, blRadiusY, tlRadiusY, height);
     scale = _getMin(scale, tlRadiusX, trRadiusX, width);
@@ -1472,7 +1476,7 @@ class RRect {
     if (point.dx < left || point.dx >= right || point.dy < top || point.dy >= bottom)
       return false; // outside bounding box
 
-    final RRect scaled = _scaleRadii();
+    final RRect scaled = scaleRadii();
 
     double x;
     double y;

testing/dart/rrect_test.dart

@@ -44,4 +44,56 @@ void main() {
     expect(rrect.contains(const Offset(1.7, 1.97)), isTrue);
     expect(rrect.contains(const Offset(1.0, 1.99)), isTrue);
   });
+
+  test('RRect.scaleRadii() properly constrained radii should remain unchanged', () {
+    final RRect rrect = RRect.fromRectAndCorners(
+      const Rect.fromLTRB(1.0, 1.0, 2.0, 2.0),
+      topLeft: const Radius.circular(0.5),
+      topRight: const Radius.circular(0.25),
+      bottomRight: const Radius.elliptical(0.25, 0.75),
+      bottomLeft: Radius.zero,
+    ).scaleRadii();
+
+    // check sides
+    expect(rrect.left, 1.0);
+    expect(rrect.top, 1.0);
+    expect(rrect.right, 2.0);
+    expect(rrect.bottom, 2.0);
+
+    // check corner radii
+    expect(rrect.tlRadiusX, 0.5);
+    expect(rrect.tlRadiusY, 0.5);
+    expect(rrect.trRadiusX, 0.25);
+    expect(rrect.trRadiusY, 0.25);
+    expect(rrect.blRadiusX, 0.0);
+    expect(rrect.blRadiusY, 0.0);
+    expect(rrect.brRadiusX, 0.25);
+    expect(rrect.brRadiusY, 0.75);
+  });
+
+  test('RRect.scaleRadii() sum of radii that exceed side length should properly scale', () {
+    final RRect rrect = RRect.fromRectAndCorners(
+      const Rect.fromLTRB(1.0, 1.0, 2.0, 2.0),
+      topLeft: const Radius.circular(5000.0),
+      topRight: const Radius.circular(2500.0),
+      bottomRight: const Radius.elliptical(2500.0, 7500.0),
+      bottomLeft: Radius.zero,
+    ).scaleRadii();
+
+    // check sides
+    expect(rrect.left, 1.0);
+    expect(rrect.top, 1.0);
+    expect(rrect.right, 2.0);
+    expect(rrect.bottom, 2.0);
+
+    // check corner radii
+    expect(rrect.tlRadiusX, 0.5);
+    expect(rrect.tlRadiusY, 0.5);
+    expect(rrect.trRadiusX, 0.25);
+    expect(rrect.trRadiusY, 0.25);
+    expect(rrect.blRadiusX, 0.0);
+    expect(rrect.blRadiusY, 0.0);
+    expect(rrect.brRadiusX, 0.25);
+    expect(rrect.brRadiusY, 0.75);
+  });
 }