Add scaleX and scaleY Parameters in Transform.Scale. (#92343)

packages/flutter/lib/src/widgets/basic.dart

@@ -1262,10 +1262,13 @@ class Transform extends SingleChildRenderObjectWidget {
        alignment = null,
        super(key: key, child: child);
 
-  /// Creates a widget that scales its child uniformly.
+  /// Creates a widget that scales its child along the 2D plane.
   ///
-  /// The `scale` argument must not be null. It gives the scalar by which
-  /// to multiply the `x` and `y` axes.
+  /// The `scaleX` argument provides the scalar by which to multiply the `x` axis, and the `scaleY` argument provides the scalar by which to multiply the `y` axis. Either may be omitted, in which case that axis defaults to 1.0.
+  ///
+  /// For convenience, to scale the child uniformly, instead of providing `scaleX` and `scaleY`, the `scale` parameter may be used.
+  ///
+  /// At least one of `scale`, `scaleX`, and `scaleY` must be non-null. If `scale` is provided, the other two must be null; similarly, if it is not provided, one of the other two must be provided.
   ///
   /// The [alignment] controls the origin of the scale; by default, this is
   /// the center of the box.
@@ -1293,14 +1296,18 @@ class Transform extends SingleChildRenderObjectWidget {
   ///    over a given duration.
   Transform.scale({
     Key? key,
-    required double scale,
+    double? scale,
+    double? scaleX,
+    double? scaleY,
     this.origin,
     this.alignment = Alignment.center,
     this.transformHitTests = true,
     this.filterQuality,
     Widget? child,
-  }) : transform = Matrix4.diagonal3Values(scale, scale, 1.0),
-       super(key: key, child: child);
+  })  : assert(!(scale == null && scaleX == null && scaleY == null), "At least one of 'scale', 'scaleX' and 'scaleY' is required to be non-null"),
+        assert(scale == null || (scaleX == null && scaleY == null), "If 'scale' is non-null then 'scaleX' and 'scaleY' must be left null"),
+        transform = Matrix4.diagonal3Values(scale ?? scaleX ?? 1.0, scale ?? scaleY ?? 1.0, 1.0),
+        super(key: key, child: child);
 
   /// The matrix to transform the child by during painting.
   final Matrix4 transform;

packages/flutter/test/widgets/transform_test.dart

@@ -505,6 +505,93 @@ void main() {
       matchesGoldenFile('transform_golden.BitmapRotate.png'),
     );
   });
+
+  testWidgets("Transform.scale() does not accept all three 'scale', 'scaleX' and 'scaleY' parameters to be non-null", (WidgetTester tester) async {
+    await expectLater(() {
+      tester.pumpWidget(Directionality(
+          textDirection: TextDirection.ltr,
+          child: Center(
+            child: Transform.scale(
+              scale: 1.0,
+              scaleX: 1.0,
+              scaleY: 1.0,
+              child: const SizedBox(
+                height: 100,
+                width: 100,
+              ),
+            ),
+          )));
+    }, throwsAssertionError);
+  });
+
+  testWidgets("Transform.scale() needs at least one of 'scale', 'scaleX' and 'scaleY' to be non-null, otherwise throws AssertionError", (WidgetTester tester) async {
+    await expectLater(() {
+      tester.pumpWidget(Directionality(
+          textDirection: TextDirection.ltr,
+          child: Center(
+            child: Transform.scale(
+              child: const SizedBox(
+                height: 100,
+                width: 100,
+              ),
+            ),
+          )));
+    }, throwsAssertionError);
+  });
+
+  testWidgets("Transform.scale() scales widget uniformly with 'scale' parameter", (WidgetTester tester) async {
+    const double _scale = 1.5;
+    const double _height = 100;
+    const double _width = 150;
+    await tester.pumpWidget(Directionality(
+        textDirection: TextDirection.ltr,
+        child: SizedBox(
+          height: 400,
+          width: 400,
+          child: Center(
+            child: Transform.scale(
+              scale: _scale,
+              child: Container(
+                height: _height,
+                width: _width,
+                decoration: const BoxDecoration(),
+              ),
+            ),
+          ),
+        )));
+
+    const Size _target = Size(_width * _scale, _height * _scale);
+
+    expect(tester.getBottomRight(find.byType(Container)), _target.bottomRight(tester.getTopLeft(find.byType(Container))));
+  });
+
+  testWidgets("Transform.scale() scales widget according to 'scaleX' and 'scaleY'", (WidgetTester tester) async {
+    const double _scaleX = 1.5;
+    const double _scaleY = 1.2;
+    const double _height = 100;
+    const double _width = 150;
+    await tester.pumpWidget(Directionality(
+        textDirection: TextDirection.ltr,
+        child: SizedBox(
+          height: 400,
+          width: 400,
+          child: Center(
+            child: Transform.scale(
+              scaleX: _scaleX,
+              scaleY: _scaleY,
+              child: Container(
+                height: _height,
+                width: _width,
+                decoration: const BoxDecoration(),
+              ),
+            ),
+          ),
+        )));
+
+    const Size _target = Size(_width * _scaleX, _height * _scaleY);
+
+    expect(tester.getBottomRight(find.byType(Container)), _target.bottomRight(tester.getTopLeft(find.byType(Container))));
+  });
 }
 
 class TestRectPainter extends CustomPainter {