Changed Material ease animations to fastOutSlowIn. (#5643)

Fixes #5393.

examples/flutter_gallery/lib/demo/animation_demo.dart

@@ -122,7 +122,7 @@ class _PointDemoState extends State<_PointDemo> {
   @override
   void initState() {
     super.initState();
-    _animation = new CurvedAnimation(parent: config.controller, curve: Curves.ease);
+    _animation = new CurvedAnimation(parent: config.controller, curve: Curves.fastOutSlowIn);
   }
 
   @override
@@ -287,7 +287,7 @@ class _RectangleDemoState extends State<_RectangleDemo> {
   @override
   void initState() {
     super.initState();
-    _animation = new CurvedAnimation(parent: config.controller, curve: Curves.ease);
+    _animation = new CurvedAnimation(parent: config.controller, curve: Curves.fastOutSlowIn);
   }
 
   @override

examples/flutter_gallery/lib/demo/progress_indicator_demo.dart

@@ -24,8 +24,8 @@ class _ProgressIndicatorDemoState extends State<ProgressIndicatorDemo> {
 
     _animation = new CurvedAnimation(
       parent: _controller,
-      curve: new Interval(0.0, 0.9, curve: Curves.ease),
-      reverseCurve: Curves.ease
+      curve: new Interval(0.0, 0.9, curve: Curves.fastOutSlowIn),
+      reverseCurve: Curves.fastOutSlowIn
     )..addStatusListener((AnimationStatus status) {
       if (status == AnimationStatus.dismissed)
         _controller.forward();

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

@@ -281,7 +281,7 @@ class AppBar extends StatelessWidget {
 
     final double toolBarOpacity = _toolBarOpacity(size.height, statusBarHeight);
     if (toolBarOpacity != 1.0) {
-      final double opacity = const Interval(0.25, 1.0, curve: Curves.ease).transform(toolBarOpacity);
+      final double opacity = const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn).transform(toolBarOpacity);
       if (centerStyle?.color != null)
         centerStyle = centerStyle.copyWith(color: centerStyle.color.withOpacity(opacity));
       if (sideStyle?.color != null)
@@ -357,7 +357,7 @@ class AppBar extends StatelessWidget {
           appBar,
           bottomOpacity == 1.0 ? bottom : new Opacity(
             child: bottom,
-            opacity: const Interval(0.25, 1.0, curve: Curves.ease).transform(bottomOpacity)
+            opacity: const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn).transform(bottomOpacity)
           )
         ]
       );

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

@@ -693,7 +693,7 @@ class _SortArrowState extends State<_SortArrow> {
       parent: _opacityController = new AnimationController(
         duration: config.duration
       ),
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     )
     ..addListener(_rebuild);
     _opacityController.value = config.visible ? 1.0 : 0.0;

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

@@ -94,7 +94,7 @@ class Input extends StatefulWidget {
 }
 
 const Duration _kTransitionDuration = const Duration(milliseconds: 200);
-const Curve _kTransitionCurve = Curves.ease;
+const Curve _kTransitionCurve = Curves.fastOutSlowIn;
 
 class _InputState extends State<Input> {
   GlobalKey<RawInputLineState> _rawInputLineKey = new GlobalKey<RawInputLineState>();

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

@@ -264,7 +264,7 @@ class _MaterialState extends State<Material> {
     }
     if (config.type != MaterialType.transparency) {
       contents = new AnimatedContainer(
-        curve: Curves.ease,
+        curve: Curves.fastOutSlowIn,
         duration: kThemeChangeDuration,
         decoration: new BoxDecoration(
           borderRadius: kMaterialEdges[config.type],

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

@@ -151,11 +151,11 @@ class _MergeableMaterialState extends State<MergeableMaterial> {
 
     final CurvedAnimation startAnimation = new CurvedAnimation(
       parent: controller,
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     );
     final CurvedAnimation endAnimation = new CurvedAnimation(
       parent: controller,
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     );
 
     startAnimation.addListener(_handleTick);
@@ -163,8 +163,7 @@ class _MergeableMaterialState extends State<MergeableMaterial> {
 
     final CurvedAnimation gapAnimation = new CurvedAnimation(
       parent: controller,
-      curve: Curves.ease,
-      reverseCurve: Curves.ease
+      curve: Curves.fastOutSlowIn
     );
 
     gapAnimation.addListener(_handleTick);

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

@@ -106,7 +106,7 @@ class _ScrollbarState extends State<Scrollbar> {
   @override
   void initState() {
     super.initState();
-    _opacity = new CurvedAnimation(parent: _fade, curve: Curves.ease);
+    _opacity = new CurvedAnimation(parent: _fade, curve: Curves.fastOutSlowIn);
   }
 
   @override

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

@@ -213,7 +213,7 @@ class _RenderSlider extends RenderConstrainedBox implements SemanticActionHandle
     _reactionController = new AnimationController(duration: kRadialReactionDuration);
     _reaction = new CurvedAnimation(
       parent: _reactionController,
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     )..addListener(markNeedsPaint);
     _position = new AnimationController(
       value: value,
@@ -229,7 +229,7 @@ class _RenderSlider extends RenderConstrainedBox implements SemanticActionHandle
       return;
     _value = newValue;
     if (divisions != null)
-      _position.animateTo(newValue, curve: Curves.ease);
+      _position.animateTo(newValue, curve: Curves.fastOutSlowIn);
     else
       _position.value = newValue;
   }

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

@@ -1188,10 +1188,10 @@ class _TabBarViewState<T> extends PageableListState<TabBarView<T>> implements Ta
 
     if (selectedIndex < previousSelectedIndex) {
       _updateItemsFromChildren(selectedIndex, previousSelectedIndex);
-      scrollTo(new CurveTween(curve: Curves.ease.flipped).evaluate(new ReverseAnimation(animation)));
+      scrollTo(new CurveTween(curve: Curves.fastOutSlowIn.flipped).evaluate(new ReverseAnimation(animation)));
     } else {
       _updateItemsFromChildren(previousSelectedIndex, selectedIndex);
-      scrollTo(new CurveTween(curve: Curves.ease).evaluate(animation));
+      scrollTo(new CurveTween(curve: Curves.fastOutSlowIn).evaluate(animation));
     }
   }
 
@@ -1296,7 +1296,7 @@ class TabPageSelector<T> extends StatelessWidget {
     final Color color = Theme.of(context).accentColor;
     final ColorTween selectedColor = new ColorTween(begin: Colors.transparent, end: color);
     final ColorTween previousColor = new ColorTween(begin: color, end: Colors.transparent);
-    Animation<double> animation = new CurvedAnimation(parent: selection.animation, curve: Curves.ease);
+    Animation<double> animation = new CurvedAnimation(parent: selection.animation, curve: Curves.fastOutSlowIn);
     return new AnimatedBuilder(
       animation: animation,
       builder: (BuildContext context, Widget child) {

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

@@ -416,7 +416,7 @@ class _DialState extends State<_Dial> {
     _thetaTween = new Tween<double>(begin: _getThetaForTime(config.selectedTime));
     _theta = _thetaTween.animate(new CurvedAnimation(
       parent: _thetaController,
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     ))..addListener(() => setState(() { }));
   }
 

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

@@ -54,7 +54,7 @@ abstract class RenderToggleable extends RenderConstrainedBox implements Semantic
     _reactionController = new AnimationController(duration: kRadialReactionDuration);
     _reaction = new CurvedAnimation(
       parent: _reactionController,
-      curve: Curves.ease
+      curve: Curves.fastOutSlowIn
     )..addListener(markNeedsPaint);
   }
 

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

@@ -138,7 +138,7 @@ class _TooltipState extends State<Tooltip> {
         padding: config.padding,
         animation: new CurvedAnimation(
           parent: _controller,
-          curve: Curves.ease
+          curve: Curves.fastOutSlowIn
         ),
         target: target,
         verticalOffset: config.verticalOffset,