Add `splashRadius` property to `IconTheme` (#93478)

packages/flutter/lib/src/cupertino/icon_theme_data.dart

@@ -29,7 +29,7 @@ class CupertinoIconThemeData extends IconThemeData with Diagnosticable {
   /// Creates a copy of this icon theme but with the given fields replaced with
   /// the new values.
   @override
-  CupertinoIconThemeData copyWith({ Color? color, double? opacity, double? size }) {
+  CupertinoIconThemeData copyWith({ Color? color, double? opacity, double? size, double? splashRadius }) {
     return CupertinoIconThemeData(
       color: color ?? this.color,
       opacity: opacity ?? this.opacity,

packages/flutter/lib/src/material/icon_button.dart

@@ -306,6 +306,7 @@ class IconButton extends StatelessWidget {
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterial(context));
     final ThemeData theme = Theme.of(context);
+    final IconThemeData iconTheme = IconTheme.of(context);
     Color? currentColor;
     if (onPressed != null)
       currentColor = color;
@@ -319,7 +320,7 @@ class IconButton extends StatelessWidget {
       minHeight: _kMinButtonSize,
     );
     final BoxConstraints adjustedConstraints = effectiveVisualDensity.effectiveConstraints(unadjustedConstraints);
-    final double effectiveIconSize = iconSize ?? IconTheme.of(context).size ?? 24.0;
+    final double effectiveIconSize = iconSize ?? iconTheme.size ?? 24.0;
 
     Widget result = ConstrainedBox(
       constraints: adjustedConstraints,
@@ -363,11 +364,12 @@ class IconButton extends StatelessWidget {
         hoverColor: hoverColor ?? theme.hoverColor,
         highlightColor: highlightColor ?? theme.highlightColor,
         splashColor: splashColor ?? theme.splashColor,
-        radius: splashRadius ?? math.max(
-          Material.defaultSplashRadius,
-          (effectiveIconSize + math.min(padding.horizontal, padding.vertical)) * 0.7,
-          // x 0.5 for diameter -> radius and + 40% overflow derived from other Material apps.
-        ),
+        radius: splashRadius ?? iconTheme.splashRadius ??
+          math.max(
+            Material.defaultSplashRadius,
+            (effectiveIconSize + math.min(padding.horizontal, padding.vertical)) * 0.7,
+            // x 0.5 for diameter -> radius and + 40% overflow derived from other Material apps.
+          ),
         child: result,
       ),
     );

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

@@ -23,7 +23,7 @@ class IconThemeData with Diagnosticable {
   ///
   /// The opacity applies to both explicit and default icon colors. The value
   /// is clamped between 0.0 and 1.0.
-  const IconThemeData({this.color, double? opacity, this.size}) : _opacity = opacity;
+  const IconThemeData({this.color, double? opacity, this.size, this.splashRadius}) : _opacity = opacity;
 
   /// Creates an icon theme with some reasonable default values.
   ///
@@ -31,15 +31,17 @@ class IconThemeData with Diagnosticable {
   const IconThemeData.fallback()
     : color = const Color(0xFF000000),
       _opacity = 1.0,
-      size = 24.0;
+      size = 24.0,
+      splashRadius = null;
 
   /// Creates a copy of this icon theme but with the given fields replaced with
   /// the new values.
-  IconThemeData copyWith({ Color? color, double? opacity, double? size }) {
+  IconThemeData copyWith({ Color? color, double? opacity, double? size, double? splashRadius }) {
     return IconThemeData(
       color: color ?? this.color,
       opacity: opacity ?? this.opacity,
       size: size ?? this.size,
+      splashRadius: splashRadius ?? this.splashRadius,
     );
   }
 
@@ -53,6 +55,7 @@ class IconThemeData with Diagnosticable {
       color: other.color,
       opacity: other.opacity,
       size: other.size,
+      splashRadius: other.splashRadius,
     );
   }
 
@@ -87,6 +90,9 @@ class IconThemeData with Diagnosticable {
   /// The default size for icons.
   final double? size;
 
+  /// The default splash radius for [IconButton]s.
+  final double? splashRadius;
+
   /// Linearly interpolate between two icon theme data objects.
   ///
   /// {@macro dart.ui.shadow.lerp}
@@ -96,6 +102,7 @@ class IconThemeData with Diagnosticable {
       color: Color.lerp(a?.color, b?.color, t),
       opacity: ui.lerpDouble(a?.opacity, b?.opacity, t),
       size: ui.lerpDouble(a?.size, b?.size, t),
+      splashRadius: ui.lerpDouble(a?.splashRadius, b?.splashRadius, t),
     );
   }
 
@@ -106,11 +113,12 @@ class IconThemeData with Diagnosticable {
     return other is IconThemeData
         && other.color == color
         && other.opacity == opacity
-        && other.size == size;
+        && other.size == size
+        && other.splashRadius == splashRadius;
   }
 
   @override
-  int get hashCode => hashValues(color, opacity, size);
+  int get hashCode => hashValues(color, opacity, size, splashRadius);
 
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
@@ -118,5 +126,6 @@ class IconThemeData with Diagnosticable {
     properties.add(ColorProperty('color', color, defaultValue: null));
     properties.add(DoubleProperty('opacity', opacity, defaultValue: null));
     properties.add(DoubleProperty('size', size, defaultValue: null));
+    properties.add(DoubleProperty('splashRadius', splashRadius, defaultValue: null));
   }
 }

packages/flutter/test/material/icon_button_test.dart

@@ -480,6 +480,40 @@ void main() {
     await gesture.up();
   });
 
+  testWidgets('IconButton can inherit splashRadius from IconTheme', (WidgetTester tester) async {
+    const double splashRadius = 30.0;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: IconTheme(
+              data: const IconThemeData(
+                splashRadius: splashRadius,
+              ),
+              child: IconButton(
+                icon: const Icon(Icons.android),
+                onPressed: () { /* enable the button */ },
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final Offset center = tester.getCenter(find.byType(IconButton));
+    final TestGesture gesture = await tester.startGesture(center);
+    await tester.pump(); // Start gesture.
+    await tester.pump(const Duration(milliseconds: 1000)); // Wait for splash to be well under way.
+
+    expect(
+      Material.of(tester.element(find.byType(IconButton))),
+      paints
+        ..circle(radius: splashRadius),
+    );
+
+    await gesture.up();
+  });
+
   testWidgets('IconButton Semantics (enabled)', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
 

packages/flutter/test/widgets/icon_theme_data_test.dart

@@ -7,7 +7,7 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   test('IconThemeData control test', () {
-    const IconThemeData data = IconThemeData(color: Color(0xAAAAAAAA), opacity: 0.5, size: 16.0);
+    const IconThemeData data = IconThemeData(color: Color(0xAAAAAAAA), opacity: 0.5, size: 16.0, splashRadius: 30.0);
 
     expect(data, hasOneLineDescription);
     expect(data, equals(data.copyWith()));
@@ -17,24 +17,27 @@ void main() {
     expect(lerped.color, const Color(0xBF7F7F7F));
     expect(lerped.opacity, 0.625);
     expect(lerped.size, 18.0);
+    expect(lerped.splashRadius, 22.5);
   });
 
   test('IconThemeData lerp with first null', () {
-    const IconThemeData data = IconThemeData(color: Color(0xFFFFFFFF), opacity: 1.0, size: 16.0);
+    const IconThemeData data = IconThemeData(color: Color(0xFFFFFFFF), opacity: 1.0, size: 16.0, splashRadius: 30.0);
 
     final IconThemeData lerped = IconThemeData.lerp(null, data, 0.25);
     expect(lerped.color, const Color(0x40FFFFFF));
     expect(lerped.opacity, 0.25);
     expect(lerped.size, 4.0);
+    expect(lerped.splashRadius, 7.5);
   });
 
   test('IconThemeData lerp with second null', () {
-    const IconThemeData data = IconThemeData(color: Color(0xFFFFFFFF), opacity: 1.0, size: 16.0);
+    const IconThemeData data = IconThemeData(color: Color(0xFFFFFFFF), opacity: 1.0, size: 16.0, splashRadius: 30.0);
 
     final IconThemeData lerped = IconThemeData.lerp(data, null, 0.25);
     expect(lerped.color, const Color(0xBFFFFFFF));
     expect(lerped.opacity, 0.75);
     expect(lerped.size, 12.0);
+    expect(lerped.splashRadius, 22.5);
   });
 
   test('IconThemeData lerp with both null', () {
@@ -42,5 +45,6 @@ void main() {
     expect(lerped.color, null);
     expect(lerped.opacity, null);
     expect(lerped.size, null);
+    expect(lerped.splashRadius, null);
   });
 }