Revert Ballistic & Clamping simulation updates (#111201)

dev/tools/generate_android_spline_data.dart

@@ -1,61 +0,0 @@
-// Copyright 2014 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.
-
-const int _nbSamples = 100;
-final List<double> _splinePosition = List<double>.filled(_nbSamples + 1, 0.0);
-final List<double> _splineTime = List<double>.filled(_nbSamples + 1, 0.0);
-const double _startTension = 0.5;
-const double _endTension = 1.0;
-const double _inflexion = 0.35;
-
-// Generate the spline data used in ClampingScrollSimulation.
-//
-// This logic is a translation of the 2-dimensional logic found in
-// https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/widget/Scroller.java.
-//
-// The output of this program should be copied over to [_splinePosition] in
-// flutter/packages/flutter/lib/src/widgets/scroll_simulation.dart.
-void main() {
-  const double p1 = _startTension * _inflexion;
-  const double p2 = 1.0 - _endTension * (1.0 - _inflexion);
-  double xMin = 0.0;
-  double yMin = 0.0;
-  for (int i = 0; i < _nbSamples; i++) {
-    final double alpha = i / _nbSamples;
-    double xMax = 1.0;
-    double x, tx, coef;
-    while (true) {
-      x = xMin + (xMax - xMin) / 2.0;
-      coef = 3.0 * x * (1.0 - x);
-      tx = coef * ((1.0 - x) * p1 + x * p2) + x * x * x;
-      if ((tx - alpha).abs() < 1e-5) {
-        break;
-      }
-      if (tx > alpha) {
-        xMax = x;
-      } else {
-        xMin = x;
-      }
-    }
-    _splinePosition[i] = coef * ((1.0 - x) * _startTension + x) + x * x * x;
-    double yMax = 1.0;
-    double y, dy;
-    while (true) {
-      y = yMin + (yMax - yMin) / 2.0;
-      coef = 3.0 * y * (1.0 - y);
-      dy = coef * ((1.0 - y) * _startTension + y) + y * y * y;
-      if ((dy - alpha).abs() < 1e-5) {
-        break;
-      }
-      if (dy > alpha) {
-        yMax = y;
-      } else {
-        yMin = y;
-      }
-    }
-    _splineTime[i] = coef * ((1.0 - y) * p1 + y * p2) + y * y * y;
-  }
-  _splinePosition[_nbSamples] = _splineTime[_nbSamples] = 1.0;
-  print(_splinePosition);
-}

packages/flutter/lib/src/animation/animation_controller.dart

@@ -757,15 +757,6 @@ class AnimationController extends Animation<double>
     return result;
   }
 
-  /// Update the simulation without restarting the animation.
-  ///
-  /// The current simulation will be replaced with the provided [Simulation].
-  /// It is only valid to call this when an animation is currently underway.
-  void updateSimulation(Simulation simulation) {
-    assert(isAnimating);
-    _simulation = simulation;
-  }
-
   /// Stops running this animation.
   ///
   /// This does not trigger any notifications. The animation stops in its

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

@@ -686,12 +686,6 @@ class _NestedScrollCoordinator implements ScrollActivityDelegate, ScrollHoldCont
     );
   }
 
-  // TODO(Piinks): https://github.com/flutter/flutter/issues/100748
-  @override
-  Simulation? updateBallisticAnimation(double initVelocity, double initPosition) {
-    return null;
-  }
-
   ScrollActivity createOuterBallisticScrollActivity(double velocity) {
     // This function creates a ballistic scroll for the outer scrollable.
     //
@@ -1367,12 +1361,6 @@ class _NestedScrollPosition extends ScrollPosition implements ScrollActivityDele
     ));
   }
 
-  // TODO(Piinks): see https://github.com/flutter/flutter/issues/100748
-  @override
-  Simulation? updateBallisticAnimation(double initVelocity, double initPosition) {
-    return null;
-  }
-
   ScrollActivity createBallisticScrollActivity(
     Simulation? simulation, {
     required _NestedBallisticScrollActivityMode mode,

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

@@ -47,16 +47,6 @@ abstract class ScrollActivityDelegate {
   /// Terminate the current activity and start a ballistic activity with the
   /// given velocity.
   void goBallistic(double velocity);
-
-  /// Update the ballistic animation instead of restarting it, for example as
-  /// the result of a layout change after a flinging gesture.
-  ///
-  /// The [initVelocity] and [initPosition] refer to the starting values of the
-  /// new ballistic animation.
-  ///
-  /// Can return null if the current [ScrollPhysics.createBallisticSimulation]
-  /// returns null, which will trigger an [IdleScrollActivity] instead.
-  Simulation? updateBallisticAnimation(double initVelocity, double initPosition);
 }
 
 /// Base class for scrolling activities like dragging and flinging.
@@ -534,17 +524,13 @@ class DragScrollActivity extends ScrollActivity {
 class BallisticScrollActivity extends ScrollActivity {
   /// Creates an activity that animates a scroll view based on a [simulation].
   ///
-  /// The [delegate], [simulation], and [vsync] arguments must not be null. The
+  /// The [delegate], [simulation], and [vsync] arguments must not be null.
-  /// [initVelocity] and [initPosition] arguments allow the ballistic activity
-  /// to update the simulation instead of restarting it.
   BallisticScrollActivity(
     super.delegate,
     Simulation simulation,
     TickerProvider vsync,
-    this.shouldIgnorePointer, {
+    this.shouldIgnorePointer,
-    double initVelocity = 0.0,
+  ) {
-    double initPosition = 0.0,
-  }) : _initVelocity = initVelocity, _initPosition = initPosition {
     _controller = AnimationController.unbounded(
       debugLabel: kDebugMode ? objectRuntimeType(this, 'BallisticScrollActivity') : null,
       vsync: vsync,
@@ -556,10 +542,6 @@ class BallisticScrollActivity extends ScrollActivity {
 
   late AnimationController _controller;
 
-  final double _initVelocity;
-
-  final double _initPosition;
-
   @override
   void resetActivity() {
     delegate.goBallistic(velocity);
@@ -567,13 +549,7 @@ class BallisticScrollActivity extends ScrollActivity {
 
   @override
   void applyNewDimensions() {
-    final Simulation? newSimulation = delegate.updateBallisticAnimation(
+    delegate.goBallistic(velocity);
-      _initVelocity,
-      _initPosition,
-    );
-    if (newSimulation != null) {
-      _controller.updateSimulation(newSimulation);
-    }
   }
 
   void _tick() {

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

@@ -12,7 +12,6 @@ import 'basic.dart';
 import 'framework.dart';
 import 'scroll_activity.dart';
 import 'scroll_context.dart';
-import 'scroll_metrics.dart';
 import 'scroll_notification.dart';
 import 'scroll_physics.dart';
 import 'scroll_position.dart';
@@ -147,35 +146,12 @@ class ScrollPositionWithSingleContext extends ScrollPosition implements ScrollAc
         simulation,
         context.vsync,
         activity?.shouldIgnorePointer ?? true,
-        initVelocity: velocity,
-        initPosition: pixels,
       ));
     } else {
       goIdle();
     }
   }
 
-  @override
-  Simulation? updateBallisticAnimation(double initVelocity, double initPosition) {
-    assert(hasPixels);
-    final FixedScrollMetrics initScrollMetrics = FixedScrollMetrics(
-      minScrollExtent: minScrollExtent,
-      maxScrollExtent: maxScrollExtent,
-      pixels: initPosition,
-      viewportDimension: viewportDimension,
-      axisDirection: axisDirection,
-    );
-    final Simulation? simulation = physics.createBallisticSimulation(
-      initScrollMetrics,
-      initVelocity,
-    );
-    if (simulation == null) {
-      goIdle();
-      return null;
-    }
-    return simulation;
-  }
-
   @override
   ScrollDirection get userScrollDirection => _userScrollDirection;
   ScrollDirection _userScrollDirection = ScrollDirection.idle;

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

@@ -146,13 +146,11 @@ class ClampingScrollSimulation extends Simulation {
     required this.velocity,
     this.friction = 0.015,
     super.tolerance,
-  }) {
+  }) : assert(_flingVelocityPenetration(0.0) == _initialVelocityPenetration) {
-    _duration = _splineFlingDuration(velocity);
+    _duration = _flingDuration(velocity);
-    _distance = _splineFlingDistance(velocity);
+    _distance = (velocity * _duration / _initialVelocityPenetration).abs();
   }
 
-  final double _inflexion = 0.35;
-
   /// The position of the particle at the beginning of the simulation.
   final double position;
 
@@ -165,7 +163,7 @@ class ClampingScrollSimulation extends Simulation {
   /// The more friction the particle experiences, the sooner it stops.
   final double friction;
 
-  late int _duration;
+  late double _duration;
   late double _distance;
 
   // See DECELERATION_RATE.
@@ -173,186 +171,59 @@ class ClampingScrollSimulation extends Simulation {
 
   // See computeDeceleration().
   static double _decelerationForFriction(double friction) {
-    return 9.80665 *
+    return friction * 61774.04968;
-      39.37 *
-      friction *
-      1.0 * // Flutter operates on logical pixels so the DPI should be 1.0.
-      160.0;
   }
 
-  // See getSplineDeceleration().
+  // See getSplineFlingDuration(). Returns a value in seconds.
-  double _splineDeceleration(double velocity) {
+  double _flingDuration(double velocity) {
-    return math.log(_inflexion *
+    // See mPhysicalCoeff
-      velocity.abs() /
+    final double scaledFriction = friction * _decelerationForFriction(0.84);
-      (friction * _decelerationForFriction(0.84)));
+
+    // See getSplineDeceleration().
+    final double deceleration = math.log(0.35 * velocity.abs() / scaledFriction);
+
+    return math.exp(deceleration / (_kDecelerationRate - 1.0));
   }
 
-  // See getSplineFlingDuration().
+  // Based on a cubic curve fit to the Scroller.computeScrollOffset() values
-  int _splineFlingDuration(double velocity) {
+  // produced for an initial velocity of 4000. The value of Scroller.getDuration()
-    final double deceleration = _splineDeceleration(velocity);
+  // and Scroller.getFinalY() were 686ms and 961 pixels respectively.
-    return (1000 * math.exp(deceleration / (_kDecelerationRate - 1.0))).round();
+  //
+  // Algebra courtesy of Wolfram Alpha.
+  //
+  // f(x) = scrollOffset, x is time in milliseconds
+  // f(x) = 3.60882×10^-6 x^3 - 0.00668009 x^2 + 4.29427 x - 3.15307
+  // f(x) = 3.60882×10^-6 x^3 - 0.00668009 x^2 + 4.29427 x, so f(0) is 0
+  // f(686ms) = 961 pixels
+  // Scale to f(0 <= t <= 1.0), x = t * 686
+  // f(t) = 1165.03 t^3 - 3143.62 t^2 + 2945.87 t
+  // Scale f(t) so that 0.0 <= f(t) <= 1.0
+  // f(t) = (1165.03 t^3 - 3143.62 t^2 + 2945.87 t) / 961.0
+  //      = 1.2 t^3 - 3.27 t^2 + 3.065 t
+  static const double _initialVelocityPenetration = 3.065;
+  static double _flingDistancePenetration(double t) {
+    return (1.2 * t * t * t) - (3.27 * t * t) + (_initialVelocityPenetration * t);
   }
 
-  // See getSplineFlingDistance().
+  // The derivative of the _flingDistancePenetration() function.
-  double _splineFlingDistance(double velocity) {
+  static double _flingVelocityPenetration(double t) {
-    final double l = _splineDeceleration(velocity);
+    return (3.6 * t * t) - (6.54 * t) + _initialVelocityPenetration;
-    final double decelMinusOne = _kDecelerationRate - 1.0;
-    return friction *
-      _decelerationForFriction(0.84) *
-      math.exp(_kDecelerationRate / decelMinusOne * l);
   }
 
   @override
   double x(double time) {
-    if (time == 0) {
+    final double t = clampDouble(time / _duration, 0.0, 1.0);
-      return position;
+    return position + _distance * _flingDistancePenetration(t) * velocity.sign;
-    }
-    final _NBSample sample = _NBSample(time, _duration);
-    return position + (sample.distanceCoef * _distance) * velocity.sign;
   }
 
   @override
   double dx(double time) {
-    if (time == 0) {
+    final double t = clampDouble(time / _duration, 0.0, 1.0);
-      return velocity;
+    return _distance * _flingVelocityPenetration(t) * velocity.sign / _duration;
-    }
-    final _NBSample sample = _NBSample(time, _duration);
-    return sample.velocityCoef * _distance / _duration * velocity.sign * 1000.0;
   }
 
   @override
   bool isDone(double time) {
-    return time * 1000.0 >= _duration;
+    return time >= _duration;
   }
 }
-
-class _NBSample {
-  _NBSample(double time, int duration) {
-    // See computeScrollOffset().
-    final double t = time * 1000.0 / duration;
-    final int index = (_nbSamples * t).clamp(0, _nbSamples).round(); // ignore_clamp_double_lint
-    _distanceCoef = 1.0;
-    _velocityCoef = 0.0;
-    if (index < _nbSamples) {
-      final double tInf = index / _nbSamples;
-      final double tSup = (index + 1) / _nbSamples;
-      final double dInf = _splinePosition[index];
-      final double dSup = _splinePosition[index + 1];
-      _velocityCoef = (dSup - dInf) / (tSup - tInf);
-      _distanceCoef = dInf + (t - tInf) * _velocityCoef;
-    }
-  }
-
-  late double _velocityCoef;
-  double get velocityCoef => _velocityCoef;
-
-  late double _distanceCoef;
-  double get distanceCoef => _distanceCoef;
-
-  static const int _nbSamples = 100;
-
-  // Generated from dev/tools/generate_android_spline_data.dart.
-  static const List<double> _splinePosition = <double>[
-    0.000022888183591973643,
-    0.028561000304762274,
-    0.05705195792956655,
-    0.08538917797618413,
-    0.11349556286812107,
-    0.14129881694635613,
-    0.16877157254923383,
-    0.19581093511175632,
-    0.22239649722992452,
-    0.24843841866631658,
-    0.2740024733220569,
-    0.298967680744136,
-    0.32333234658228116,
-    0.34709556909569184,
-    0.3702249257894571,
-    0.39272483400399893,
-    0.41456988647721615,
-    0.43582889025419114,
-    0.4564192786416,
-    0.476410299013587,
-    0.4957560715637827,
-    0.5145493169954743,
-    0.5327205670880077,
-    0.5502846891191615,
-    0.5673274324802855,
-    0.583810881323224,
-    0.5997478744397482,
-    0.615194045299478,
-    0.6301165005270208,
-    0.6445484042257972,
-    0.6585198219185201,
-    0.6720397744233084,
-    0.6850997688076114,
-    0.6977281404741683,
-    0.7099506591298411,
-    0.7217749311525871,
-    0.7331784038850426,
-    0.7442308394229518,
-    0.7549087205105974,
-    0.7652471277371271,
-    0.7752251637549381,
-    0.7848768260203478,
-    0.7942056937103814,
-    0.8032299679689082,
-    0.8119428702388629,
-    0.8203713516576219,
-    0.8285187880808974,
-    0.8363794492831295,
-    0.8439768562813565,
-    0.851322799855549,
-    0.8584111051351724,
-    0.8652534074722162,
-    0.8718525580962131,
-    0.8782333271742155,
-    0.8843892099362031,
-    0.8903155590440985,
-    0.8960465359221951,
-    0.9015574505919048,
-    0.9068736766459904,
-    0.9119951682409297,
-    0.9169321898723632,
-    0.9216747065581234,
-    0.9262420604674766,
-    0.9306331858366086,
-    0.9348476990715433,
-    0.9389007110754832,
-    0.9427903495057521,
-    0.9465220679845756,
-    0.9500943036519721,
-    0.9535176728088761,
-    0.9567898524767604,
-    0.959924306623116,
-    0.9629127700159108,
-    0.9657622101750765,
-    0.9684818726275105,
-    0.9710676079044347,
-    0.9735231939498,
-    0.9758514437576309,
-    0.9780599066560445,
-    0.9801485715370128,
-    0.9821149805689633,
-    0.9839677526782791,
-    0.9857085499421516,
-    0.9873347811966005,
-    0.9888547171706613,
-    0.9902689443512227,
-    0.9915771042095881,
-    0.9927840651641069,
-    0.9938913963715834,
-    0.9948987305580712,
-    0.9958114963810524,
-    0.9966274782266875,
-    0.997352148697352,
-    0.9979848677523623,
-    0.9985285021374979,
-    0.9989844084453229,
-    0.9993537595844986,
-    0.999638729860106,
-    0.9998403888004533,
-    0.9999602810470701,
-    1.0
-  ];
-}

packages/flutter/test/widgets/scroll_activity_test.dart

@@ -129,64 +129,6 @@ void main() {
     expect(find.text('Page 9'), findsOneWidget);
   });
 
-  List<Widget> childrenSizeIncrease(int n) {
-    return List<Widget>.generate(n, (int i) {
-      return SizedBox(height: 40.0 + i * 3, child: Text('$i'));
-    });
-  }
-
-  testWidgets('Check for duplicate pixels with ClampingScrollPhysics', (WidgetTester tester) async {
-    final List<double> scrollSimulationXList = <double>[];
-    final TestScrollPhysics testScrollPhysics = TestScrollPhysics(
-      scrollSimulationXList,
-      parent: const ClampingScrollPhysics(),
-    );
-    await tester.pumpWidget(
-      MaterialApp(
-        home: ListView(
-          physics: testScrollPhysics,
-          children: childrenSizeIncrease(100),
-        ),
-      ),
-    );
-    await tester.fling(find.byType(ListView), const Offset(0.0, -4000.0), 4000.0);
-    await tester.pumpAndSettle();
-    final Set<double> checkSet = <double>{};
-    checkSet.addAll(scrollSimulationXList);
-    /// checkSet.length + 1 is because:
-    /// simulation.x(0.0) will be called in _startSimulation.
-    /// The first frame of the animation will also call simulation.x(0.0).
-    /// It can be tolerated that it has at most one duplicate value.
-    final bool hasOnlyOneDuplicate = scrollSimulationXList.length == checkSet.length + 1;
-    expect(true, hasOnlyOneDuplicate); // and ends up at the end
-  });
-
-  testWidgets('Check for duplicate pixels with BouncingScrollPhysics', (WidgetTester tester) async {
-    final List<double> scrollSimulationXList = <double>[];
-    final TestScrollPhysics testScrollPhysics = TestScrollPhysics(
-      scrollSimulationXList,
-      parent: const BouncingScrollPhysics(),
-    );
-    await tester.pumpWidget(
-      MaterialApp(
-        home: ListView(
-          physics: testScrollPhysics,
-          children: childrenSizeIncrease(100),
-        ),
-      ),
-    );
-    await tester.fling(find.byType(ListView), const Offset(0.0, -4000.0), 4000.0);
-    await tester.pumpAndSettle();
-    final Set<double> checkSet = <double>{};
-    checkSet.addAll(scrollSimulationXList);
-    /// checkSet.length + 1 is because:
-    /// simulation.x(0.0) will be call in _startSimulation.
-    /// The first frame of the animation will also call simulation.x(0.0).
-    /// It can be tolerated that it has at most one duplicate value.
-    final bool noDuplicate = scrollSimulationXList.length == checkSet.length + 1;
-    expect(true, noDuplicate); // and ends up at the end
-  });
-
   testWidgets('Pointer is not ignored during trackpad scrolling.', (WidgetTester tester) async {
     final ScrollController controller = ScrollController();
     int? lastTapped;
@@ -268,62 +210,6 @@ void main() {
   });
 }
 
-class TestScrollPhysics extends ScrollPhysics {
-  const TestScrollPhysics(this.scrollSimulationXList, { super.parent });
-
-  final List<double> scrollSimulationXList;
-
-  @override
-  Simulation? createBallisticSimulation(
-    ScrollMetrics position,
-    double velocity,
-  ) {
-    final Simulation? scrollSimulation = super.createBallisticSimulation(
-      position,
-      velocity,
-    );
-    if (scrollSimulation != null && scrollSimulationXList != null) {
-      return TestScrollScrollSimulation(
-        scrollSimulation,
-        scrollSimulationXList,
-      );
-    }
-    return scrollSimulation;
-  }
-
-  @override
-  TestScrollPhysics applyTo(ScrollPhysics? ancestor) {
-    return TestScrollPhysics(
-      scrollSimulationXList,
-      parent: buildParent(ancestor),
-    );
-  }
-}
-
-class TestScrollScrollSimulation extends Simulation {
-  TestScrollScrollSimulation(this.innerScrollSimulation,
-      this.scrollSimulationXList,);
-
-  final Simulation innerScrollSimulation;
-
-  final List<double> scrollSimulationXList;
-
-  @override
-  double dx(double time) => innerScrollSimulation.dx(time);
-
-  @override
-  bool isDone(double time) => innerScrollSimulation.isDone(time);
-
-  @override
-  double x(double time) {
-    final double simulationX = innerScrollSimulation.x(time);
-    if (scrollSimulationXList != null) {
-      scrollSimulationXList.add(simulationX);
-    }
-    return simulationX;
-  }
-}
-
 class PageView62209 extends StatefulWidget {
   const PageView62209({super.key});
 

packages/flutter/test/widgets/scroll_simulation_test.dart

@@ -23,21 +23,4 @@ void main() {
     checkInitialConditions(75.0, 614.2093);
     checkInitialConditions(5469.0, 182.114534);
   });
-
-  test('ClampingScrollSimulation velocity eventually reaches zero', () {
-    void checkFinalConditions(double position, double velocity) {
-      final ClampingScrollSimulation simulation = ClampingScrollSimulation(position: position, velocity: velocity);
-      expect(simulation.dx(10.0), equals(0.0));
-    }
-
-    checkFinalConditions(51.0, 2000.0);
-    checkFinalConditions(584.0, 2617.294734);
-    checkFinalConditions(345.0, 1982.785934);
-    checkFinalConditions(0.0, 1831.366634);
-    checkFinalConditions(-156.2, 1541.57665);
-    checkFinalConditions(4.0, 1139.250439);
-    checkFinalConditions(4534.0, 1073.553798);
-    checkFinalConditions(75.0, 614.2093);
-    checkFinalConditions(5469.0, 182.114534);
-  });
 }

packages/flutter/test/widgets/scrollable_fling_test.dart

@@ -48,7 +48,7 @@ void main() {
     // Before changing these values, ensure the fling results in a distance that
     // makes sense. See issue for more context.
     expect(androidResult, greaterThan(394.0));
-    expect(androidResult, lessThan(408.2));
+    expect(androidResult, lessThan(395.0));
 
     await pumpTest(tester, TargetPlatform.linux);
     await tester.fling(find.byType(ListView), const Offset(0.0, -dragOffset), 1000.0);
@@ -152,6 +152,6 @@ void main() {
     expect(log, equals(<String>['tap 21']));
     await tester.tap(find.byType(Scrollable));
     await tester.pump(const Duration(milliseconds: 50));
-    expect(log, equals(<String>['tap 21', 'tap 49']));
+    expect(log, equals(<String>['tap 21', 'tap 48']));
   });
 }

packages/flutter/test/widgets/scrollable_semantics_test.dart

@@ -231,7 +231,7 @@ void main() {
 
     expect(semantics, includesNodeWith(
       scrollExtentMin: 0.0,
-      scrollPosition: 394.3,
+      scrollPosition: 380.2,
       scrollExtentMax: 520.0,
       actions: <SemanticsAction>[
         SemanticsAction.scrollUp,
@@ -280,7 +280,7 @@ void main() {
 
     expect(semantics, includesNodeWith(
       scrollExtentMin: 0.0,
-      scrollPosition: 394.3,
+      scrollPosition: 380.2,
       scrollExtentMax: double.infinity,
       actions: <SemanticsAction>[
         SemanticsAction.scrollUp,
@@ -292,7 +292,7 @@ void main() {
 
     expect(semantics, includesNodeWith(
       scrollExtentMin: 0.0,
-      scrollPosition: 788.6,
+      scrollPosition: 760.4,
       scrollExtentMax: double.infinity,
       actions: <SemanticsAction>[
         SemanticsAction.scrollUp,

packages/flutter/test/widgets/scrollable_test.dart

@@ -946,8 +946,8 @@ void main() {
     expect(find.byKey(const ValueKey<String>('Box 0')), findsNothing);
     expect(find.byKey(const ValueKey<String>('Box 52')), findsOneWidget);
 
-    expect(expensiveWidgets, 40);
+    expect(expensiveWidgets, 38);
-    expect(cheapWidgets, 21);
+    expect(cheapWidgets, 20);
   });
 
   testWidgets('Can recommendDeferredLoadingForContext - override heuristic', (WidgetTester tester) async {
@@ -989,9 +989,9 @@ void main() {
     expect(find.byKey(const ValueKey<String>('Box 0')), findsNothing);
     expect(find.byKey(const ValueKey<String>('Cheap box 52')), findsOneWidget);
 
-    expect(expensiveWidgets, 17);
+    expect(expensiveWidgets, 18);
-    expect(cheapWidgets, 44);
+    expect(cheapWidgets, 40);
-    expect(physics.count, 44 + 17);
+    expect(physics.count, 40 + 18);
   });
 
   testWidgets('Can recommendDeferredLoadingForContext - override heuristic and always return true', (WidgetTester tester) async {
@@ -1032,7 +1032,7 @@ void main() {
     expect(find.byKey(const ValueKey<String>('Cheap box 52')), findsOneWidget);
 
     expect(expensiveWidgets, 0);
-    expect(cheapWidgets, 61);
+    expect(cheapWidgets, 58);
   });
 
   testWidgets('ensureVisible does not move PageViews', (WidgetTester tester) async {
@@ -1439,9 +1439,9 @@ void main() {
     await tester.sendEventToBinding(testPointer.hover(tester.getCenter(find.byType(Scrollable))));
     await tester.sendEventToBinding(testPointer.scrollInertiaCancel()); // Cancel partway through.
     await tester.pump();
-    expect(getScrollOffset(tester), closeTo(342.5439, 0.0001));
+    expect(getScrollOffset(tester), closeTo(333.2944, 0.0001));
     await tester.pump(const Duration(milliseconds: 4800));
-    expect(getScrollOffset(tester), closeTo(342.5439, 0.0001));
+    expect(getScrollOffset(tester), closeTo(333.2944, 0.0001));
   });
 }
 

packages/flutter/test/widgets/slivers_appbar_floating_pinned_test.dart

@@ -151,7 +151,7 @@ void main() {
     );
     expect(semantics, hasSemantics(expectedSemantics, ignoreTransform: true, ignoreId: true, ignoreRect: true));
 
-    await tester.fling(find.text('Tile 2'), const Offset(0, -600), 1950);
+    await tester.fling(find.text('Tile 2'), const Offset(0, -600), 2000);
     await tester.pumpAndSettle();
 
     expectedSemantics = TestSemantics.root(