Adjust remaining Cupertino route animations to match native (#28597)

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

@@ -417,9 +417,13 @@ class CupertinoFullscreenDialogTransition extends StatelessWidget {
     Key key,
     @required Animation<double> animation,
     @required this.child,
-  }) : _positionAnimation = animation
-         .drive(CurveTween(curve: Curves.easeInOut))
-         .drive(_kBottomUpTween),
+  }) : _positionAnimation = CurvedAnimation(
+         parent: animation,
+         curve: Curves.linearToEaseOut,
+         // The curve must be flipped so that the reverse animation doesn't play
+         // an ease-in curve, which iOS does not use.
+         reverseCurve: Curves.linearToEaseOut.flipped,
+       ).drive(_kBottomUpTween),
        super(key: key);
 
   final Animation<Offset> _positionAnimation;
@@ -816,8 +820,11 @@ class _CupertinoModalPopupRoute<T> extends PopupRoute<T> {
     assert(_animation == null);
     _animation = CurvedAnimation(
       parent: super.createAnimation(),
-      curve: Curves.ease,
-      reverseCurve: Curves.ease.flipped,
+
+      // These curves were initially measured from native iOS horizontal page
+      // route animations and seemed to be a good match here as well.
+      curve: Curves.linearToEaseOut,
+      reverseCurve: Curves.linearToEaseOut.flipped,
     );
     _offsetTween = Tween<Offset>(
       begin: const Offset(0.0, 1.0),
@@ -879,8 +886,11 @@ Future<T> showCupertinoModalPopup<T>({
   );
 }
 
-final Animatable<double> _dialogTween = Tween<double>(begin: 1.2, end: 1.0)
-  .chain(CurveTween(curve: Curves.fastOutSlowIn));
+// The curve and initial scale values were mostly eyeballed from iOS, however
+// they reuse the same animation curve that was modelled after native page
+// transitions.
+final Animatable<double> _dialogScaleTween = Tween<double>(begin: 1.3, end: 1.0)
+  .chain(CurveTween(curve: Curves.linearToEaseOut));
 
 Widget _buildCupertinoDialogTransitions(BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation, Widget child) {
   final CurvedAnimation fadeAnimation = CurvedAnimation(
@@ -897,7 +907,7 @@ Widget _buildCupertinoDialogTransitions(BuildContext context, Animation<double>
     opacity: fadeAnimation,
     child: ScaleTransition(
       child: child,
-      scale: animation.drive(_dialogTween),
+      scale: animation.drive(_dialogScaleTween),
     ),
   );
 }
@@ -941,7 +951,8 @@ Future<T> showCupertinoDialog<T>({
     context: context,
     barrierDismissible: false,
     barrierColor: _kModalBarrierColor,
-    transitionDuration: const Duration(milliseconds: 300),
+    // This transition duration was eyeballed comparing with iOS
+    transitionDuration: const Duration(milliseconds: 250),
     pageBuilder: (BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation) {
       return builder(context);
     },

packages/flutter/test/cupertino/action_sheet_test.dart

@@ -718,19 +718,19 @@ void main() {
     expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, 600.0);
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(530.9, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(470.0, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(426.7, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(374.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(365.0, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(337.1, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(334.0, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(325.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(321.0, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(320.8, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
     expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(319.3, 0.1));
@@ -745,19 +745,19 @@ void main() {
     expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(319.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(388.4, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(449.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(492.6, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(544.9, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(554.2, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(582.1, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(585.2, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(593.9, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(598.2, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(598.5, 0.1));
 
     // Action sheet has disappeared
     await tester.pump(const Duration(milliseconds: 60));
@@ -795,23 +795,23 @@ void main() {
     expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, 600.0);
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(530.9, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(470.0, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(426.7, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(374.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(365.0, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(337.1, 0.1));
 
     // Exit animation
     await tester.tapAt(const Offset(20.0, 20.0));
     await tester.pump(const Duration(milliseconds: 60));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(426.7, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(374.3, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
-    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(530.9, 0.1));
+    expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, closeTo(470.0, 0.1));
 
     await tester.pump(const Duration(milliseconds: 60));
     expect(tester.getTopLeft(find.byType(CupertinoActionSheet)).dy, 600.0);

packages/flutter/test/cupertino/dialog_test.dart

@@ -847,27 +847,27 @@ void main() {
     // Enter animation.
     await tester.pump();
     Transform transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.2, 0.01));
+    expect(transform.transform[0], closeTo(1.3, 0.01));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.182, 0.001));
+    expect(transform.transform[0], closeTo(1.145, 0.001));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.108, 0.001));
+    expect(transform.transform[0], closeTo(1.044, 0.001));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.044, 0.001));
+    expect(transform.transform[0], closeTo(1.013, 0.001));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.015, 0.001));
+    expect(transform.transform[0], closeTo(1.003, 0.001));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
-    expect(transform.transform[0], closeTo(1.003, 0.001));
+    expect(transform.transform[0], closeTo(1.000, 0.001));
 
     await tester.pump(const Duration(milliseconds: 50));
     transform = tester.widget(find.byType(Transform));
@@ -951,23 +951,23 @@ void main() {
     // Exit animation, look at reverse FadeTransition.
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);
-    expect(transition.opacity.value, closeTo(0.358, 0.001));
+    expect(transition.opacity.value, closeTo(0.500, 0.001));
 
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);
-    expect(transition.opacity.value, closeTo(0.231, 0.001));
+    expect(transition.opacity.value, closeTo(0.332, 0.001));
 
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);
-    expect(transition.opacity.value, closeTo(0.128, 0.001));
+    expect(transition.opacity.value, closeTo(0.188, 0.001));
 
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);
-    expect(transition.opacity.value, closeTo(0.056, 0.001));
+    expect(transition.opacity.value, closeTo(0.081, 0.001));
 
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);
-    expect(transition.opacity.value, closeTo(0.013, 0.001));
+    expect(transition.opacity.value, closeTo(0.019, 0.001));
 
     await tester.pump(const Duration(milliseconds: 25));
     transition = tester.widgetList(find.byType(FadeTransition)).elementAt(1);

packages/flutter/test/cupertino/route_test.dart

@@ -328,4 +328,107 @@ void main() {
     expect(find.text('route'), findsOneWidget);
     expect(find.text('push'), findsNothing);
   });
+
+  testWidgets('Fullscreen route animates correct transform values over time', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Builder(
+          builder: (BuildContext context) {
+            return CupertinoButton(
+              child: const Text('Button'),
+              onPressed: () {
+                Navigator.push<void>(context, CupertinoPageRoute<void>(
+                  fullscreenDialog: true,
+                  builder: (BuildContext context) {
+                    return Column(
+                      children: <Widget>[
+                        const Placeholder(),
+                        CupertinoButton(
+                          child: const Text('Close'),
+                          onPressed: () {
+                            Navigator.pop<void>(context);
+                          },
+                        )
+                      ],
+                    );
+                  },
+                ));
+              },
+            );
+          }
+        ),
+      ),
+    );
+
+    // Enter animation.
+    await tester.tap(find.text('Button'));
+    await tester.pump();
+
+    // We use a higher number of intervals since the animation has to scale the
+    // entire screen.
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(443.7, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(291.9, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(168.2, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(89.5, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(48.1, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(26.1, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(14.3, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(7.41, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(3.0, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(0.0, 0.1));
+
+    // Exit animation
+    await tester.tap(find.text('Close'));
+    await tester.pump();
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(156.3, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(308.1, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(431.7, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(510.4, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(551.8, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(573.8, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(585.6, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(592.6, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(596.9, 0.1));
+
+    await tester.pump(const Duration(milliseconds: 40));
+    expect(tester.getTopLeft(find.byType(Placeholder)).dy, closeTo(600.0, 0.1));
+  });
 }