[framework] respect debugDisableShadows in slider thumbs (#105467)

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

@@ -2366,7 +2366,19 @@ class RoundSliderThumbShape extends SliderComponentShape {
     final double evaluatedElevation = elevationTween.evaluate(activationAnimation);
     final Path path = Path()
       ..addArc(Rect.fromCenter(center: center, width: 2 * radius, height: 2 * radius), 0, math.pi * 2);
+
+    bool paintShadows = true;
+    assert(() {
+      if (debugDisableShadows) {
+        _debugDrawShadow(canvas, path, evaluatedElevation);
+        paintShadows = false;
+      }
+      return true;
+    }());
+
+    if (paintShadows) {
       canvas.drawShadow(path, Colors.black, evaluatedElevation, true);
+    }
 
     canvas.drawCircle(
       center,
@@ -2475,7 +2487,19 @@ class RoundRangeSliderThumbShape extends RangeSliderThumbShape {
     final double evaluatedElevation = isPressed! ? elevationTween.evaluate(activationAnimation) : elevation;
     final Path shadowPath = Path()
       ..addArc(Rect.fromCenter(center: center, width: 2 * radius, height: 2 * radius), 0, math.pi * 2);
+
+    bool paintShadows = true;
+    assert(() {
+      if (debugDisableShadows) {
+        _debugDrawShadow(canvas, shadowPath, evaluatedElevation);
+        paintShadows = false;
+      }
+      return true;
+    }());
+
+    if (paintShadows) {
       canvas.drawShadow(shadowPath, Colors.black, evaluatedElevation, true);
+    }
 
     canvas.drawCircle(
       center,
@@ -3359,3 +3383,15 @@ class RangeLabels {
     return '${objectRuntimeType(this, 'RangeLabels')}($start, $end)';
   }
 }
+
+void _debugDrawShadow(Canvas canvas, Path path, double elevation) {
+  if (elevation > 0.0) {
+    canvas.drawPath(
+      path,
+      Paint()
+        ..color = Colors.black
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = elevation * 2.0,
+    );
+  }
+}

packages/flutter/test/material/range_slider_test.dart

@@ -1276,8 +1276,10 @@ void main() {
     expect(
       valueIndicatorBox,
       paints
+        ..path(color: Colors.black) // shadow
+        ..path(color: Colors.black) // shadow
         ..path(color: sliderTheme.valueIndicatorColor)
-        ..paragraph(),
+        ..paragraph()
     );
     await gesture.up();
     // Wait for value indicator animation to finish.
@@ -1360,7 +1362,7 @@ void main() {
     );
 
     // Represents the Raised Button and Range Slider.
-    expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 4));
+    expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 6));
     expect(valueIndicatorBox, paintsExactlyCountTimes(#drawParagraph, 3));
 
     await tester.tap(find.text('Next'));
@@ -1519,6 +1521,8 @@ void main() {
     expect(
       valueIndicatorBox,
       paints
+        ..path(color: Colors.black) // shadow
+        ..path(color: Colors.black) // shadow
         ..path(color: sliderTheme.valueIndicatorColor)
         ..paragraph(),
     );
@@ -1594,6 +1598,8 @@ void main() {
     expect(
       valueIndicatorBox,
       paints
+        ..path(color: Colors.black) // shadow
+        ..path(color: Colors.black) // shadow
         ..path(color: sliderTheme.valueIndicatorColor)
         ..paragraph(),
     );

packages/flutter/test/material/slider_test.dart

@@ -627,6 +627,8 @@ void main() {
   });
 
   testWidgets('Slider uses the right theme colors for the right components', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       const Color customColor1 = Color(0xcafefeed);
       const Color customColor2 = Color(0xdeadbeef);
       final ThemeData theme = ThemeData(
@@ -838,6 +840,9 @@ void main() {
           ..path(color: sliderTheme.valueIndicatorColor), // indicator
       );
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('Slider can tap in vertical scroller', (WidgetTester tester) async {
@@ -1033,6 +1038,8 @@ void main() {
   });
 
   testWidgets('Slider respects textScaleFactor', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       final Key sliderKey = UniqueKey();
       double value = 0.0;
 
@@ -1179,6 +1186,9 @@ void main() {
 
       await gesture.up();
       await tester.pumpAndSettle();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('Tick marks are skipped when they are too dense', (WidgetTester tester) async {
@@ -2552,7 +2562,7 @@ void main() {
         ..paragraph(),
     );
 
-    expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 3));
+    expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 4));
     expect(valueIndicatorBox, paintsExactlyCountTimes(#drawParagraph, 2));
 
     await tester.tap(find.text('Next'));

packages/flutter/test/material/slider_theme_test.dart

@@ -362,6 +362,8 @@ void main() {
   });
 
   testWidgets('Default paddle slider value indicator shape draws correctly', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       final ThemeData theme = ThemeData(
         platform: TargetPlatform.android,
         primarySwatch: Colors.blue,
@@ -536,9 +538,14 @@ void main() {
           ),
       );
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('Default paddle slider value indicator shape draws correctly', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       final ThemeData theme = ThemeData(
         platform: TargetPlatform.android,
         primarySwatch: Colors.blue,
@@ -713,6 +720,9 @@ void main() {
           ),
       );
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('The slider track height can be overridden', (WidgetTester tester) async {
@@ -967,6 +977,8 @@ void main() {
   });
 
   testWidgets('The slider can skip all component painting except the thumb', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       // Pump a slider with just a thumb.
       await tester.pumpWidget(_buildApp(
         ThemeData().sliderTheme.copyWith(
@@ -985,6 +997,9 @@ void main() {
       expect(material, paintsExactlyCountTimes(#drawRect, 0));
       expect(material, paintsExactlyCountTimes(#drawCircle, 1));
       expect(material, paintsExactlyCountTimes(#drawPath, 0));
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('The slider can skip all component painting except the overlay', (WidgetTester tester) async {
@@ -1113,6 +1128,8 @@ void main() {
 
 
   testWidgets('Default paddle range slider value indicator shape draws correctly', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       final ThemeData theme = ThemeData(
         platform: TargetPlatform.android,
         primarySwatch: Colors.blue,
@@ -1155,10 +1172,60 @@ void main() {
       );
 
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
+  });
+
+  testWidgets('Default paddle range slider value indicator shape draws correctly with debugDisableShadows', (WidgetTester tester) async {
+    debugDisableShadows = true;
+    final ThemeData theme = ThemeData(
+      platform: TargetPlatform.android,
+      primarySwatch: Colors.blue,
+    );
+    final SliderThemeData sliderTheme = theme.sliderTheme.copyWith(
+      thumbColor: Colors.red.shade500,
+      showValueIndicator: ShowValueIndicator.always,
+      rangeValueIndicatorShape: const PaddleRangeSliderValueIndicatorShape(),
+    );
+
+    await tester.pumpWidget(_buildRangeApp(sliderTheme));
+
+    final RenderBox valueIndicatorBox = tester.renderObject(find.byType(Overlay));
 
+    final Offset center = tester.getCenter(find.byType(RangeSlider));
+    final TestGesture gesture = await tester.startGesture(center);
+    // Wait for value indicator animation to finish.
+    await tester.pumpAndSettle();
+    expect(
+      valueIndicatorBox,
+      paints
+        // physical model
+        ..rrect()
+        ..rrect(rrect: RRect.fromLTRBAndCorners(
+          24.0, 298.0, 24.0, 302.0,
+          topLeft: const Radius.circular(2.0),
+          bottomLeft: const Radius.circular(2.0),
+        ))
+        ..rect(rect: const Rect.fromLTRB(24.0, 297.0, 24.0, 303.0))
+        ..rrect(rrect: RRect.fromLTRBAndCorners(
+          24.0, 298.0, 776.0, 302.0,
+          topRight: const Radius.circular(2.0),
+          bottomRight: const Radius.circular(2.0),
+        ))
+        ..circle(x: 24.0, y: 300.0)
+        ..path(strokeWidth: 1.0 * 2.0, color: Colors.black)
+        ..circle(x: 24.0, y: 300.0)
+        ..path(strokeWidth: 6.0 * 2.0, color: Colors.black)
+        ..circle(x: 24.0, y: 300.0),
+    );
+
+    await gesture.up();
   });
 
   testWidgets('PaddleRangeSliderValueIndicatorShape skips all painting at zero scale', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       // Pump a slider with just a value indicator.
       await tester.pumpWidget(_buildRangeApp(
         ThemeData().sliderTheme.copyWith(
@@ -1169,7 +1236,7 @@ void main() {
         divisions: 4,
       ));
 
-//    final RenderBox sliderBox = tester.firstRenderObject<RenderBox>(find.byType(RangeSlider));
+      //  final RenderBox sliderBox = tester.firstRenderObject<RenderBox>(find.byType(RangeSlider));
       final RenderBox valueIndicatorBox = tester.renderObject(find.byType(Overlay));
 
       // Tap the center of the track to kick off the animation of the value indicator.
@@ -1185,9 +1252,14 @@ void main() {
       expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 2));
 
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('Default range indicator shape skips all painting at zero scale', (WidgetTester tester) async {
+    debugDisableShadows = false;
+    try {
       // Pump a slider with just a value indicator.
       await tester.pumpWidget(_buildRangeApp(
         ThemeData().sliderTheme.copyWith(
@@ -1216,6 +1288,9 @@ void main() {
       expect(valueIndicatorBox, paintsExactlyCountTimes(#drawPath, 2));
 
       await gesture.up();
+    } finally {
+      debugDisableShadows = true;
+    }
   });
 
   testWidgets('activeTrackRadius is taken into account when painting the border of the active track', (WidgetTester tester) async {