packages/animations/lib/src/fade_through_transition.dart - mirrors/packages - Git at Google

 // Copyright 2013 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.

 import 'package:flutter/material.dart';

 /// Used by [PageTransitionsTheme] to define a page route transition animation
 /// in which the outgoing page fades out, then the incoming page fades in and
 /// scale up.
 ///
 /// This pattern is recommended for a transition between UI elements that do not
 /// have a strong relationship to one another.
 ///
 /// Scale is only applied to incoming elements to emphasize new content over
 /// old.
 ///
 /// The following example shows how the FadeThroughPageTransitionsBuilder can
 /// be used in a [PageTransitionsTheme] to change the default transitions
 /// of [MaterialPageRoute]s.
 ///
 /// ```dart
 /// MaterialApp(
 ///   theme: ThemeData(
 ///     pageTransitionsTheme: PageTransitionsTheme(
 ///       builders: {
 ///         TargetPlatform.android: FadeThroughPageTransitionsBuilder(),
 ///         TargetPlatform.iOS: FadeThroughPageTransitionsBuilder(),
 ///       },
 ///     ),
 ///   ),
 ///   routes: {
 ///     '/': (BuildContext context) {
 ///       return Container(
 ///         color: Colors.red,
 ///         child: Center(
 ///           child: TextButton(
 ///             child: Text('Push route'),
 ///             onPressed: () {
 ///               Navigator.of(context).pushNamed('/a');
 ///             },
 ///           ),
 ///         ),
 ///       );
 ///     },
 ///     '/a' : (BuildContext context) {
 ///       return Container(
 ///         color: Colors.blue,
 ///         child: Center(
 ///           child: TextButton(
 ///             child: Text('Pop route'),
 ///             onPressed: () {
 ///               Navigator.of(context).pop();
 ///             },
 ///           ),
 ///         ),
 ///       );
 ///     },
 ///   },
 /// );
 /// ```
 class FadeThroughPageTransitionsBuilder extends PageTransitionsBuilder {
   /// Creates a [FadeThroughPageTransitionsBuilder].
   const FadeThroughPageTransitionsBuilder({this.fillColor});

   /// The color to use for the background color during the transition.
   ///
   /// This defaults to the [Theme]'s [ThemeData.canvasColor].
   final Color? fillColor;

   @override
   Widget buildTransitions<T>(
     PageRoute<T>? route,
     BuildContext? context,
     Animation<double> animation,
     Animation<double> secondaryAnimation,
     Widget child,
   ) {
     return FadeThroughTransition(
       animation: animation,
       secondaryAnimation: secondaryAnimation,
       fillColor: fillColor,
       child: child,
     );
   }
 }

 /// Defines a transition in which outgoing elements fade out, then incoming
 /// elements fade in and scale up.
 ///
 /// The fade through pattern provides a transition animation between UI elements
 /// that do not have a strong relationship to one another. As an example, the
 /// [BottomNavigationBar] may use this animation to transition the currently
 /// displayed content when a new [BottomNavigationBarItem] is selected.
 ///
 /// Scale is only applied to incoming elements to emphasize new content over
 /// old.
 ///
 /// Consider using [FadeThroughPageTransitionsBuilder] within a
 /// [PageTransitionsTheme] if you want to apply this kind of transition to
 /// [MaterialPageRoute] transitions within a Navigator (see
 /// [FadeThroughPageTransitionsBuilder] for some example code). Or use this transition
 /// directly in a [PageTransitionSwitcher.transitionBuilder] to transition
 /// from one widget to another as seen in the following example:
 ///
 /// ```dart
 ///  int _selectedIndex = 0;
 ///
 ///  final List<Color> _colors = [Colors.blue, Colors.red, Colors.yellow];
 ///
 ///  @override
 ///  Widget build(BuildContext context) {
 ///    return Scaffold(
 ///      appBar: AppBar(
 ///        title: const Text('Switcher Sample'),
 ///      ),
 ///      body: PageTransitionSwitcher(
 ///        transitionBuilder: (
 ///          Widget child,
 ///          Animation<double> primaryAnimation,
 ///          Animation<double> secondaryAnimation,
 ///        ) {
 ///          return FadeThroughTransition(
 ///            child: child,
 ///            animation: primaryAnimation,
 ///            secondaryAnimation: secondaryAnimation,
 ///          );
 ///        },
 ///        child: Container(
 ///          key: ValueKey<int>(_selectedIndex),
 ///          color: _colors[_selectedIndex],
 ///        ),
 ///      ),
 ///      bottomNavigationBar: BottomNavigationBar(
 ///        items: const <BottomNavigationBarItem>[
 ///          BottomNavigationBarItem(
 ///            icon: Icon(Icons.home),
 ///            title: Text('Blue'),
 ///          ),
 ///          BottomNavigationBarItem(
 ///            icon: Icon(Icons.business),
 ///            title: Text('Red'),
 ///          ),
 ///          BottomNavigationBarItem(
 ///            icon: Icon(Icons.school),
 ///            title: Text('Yellow'),
 ///          ),
 ///        ],
 ///        currentIndex: _selectedIndex,
 ///        selectedItemColor: Colors.amber[800],
 ///        onTap: (int index) {
 ///          setState(() {
 ///            _selectedIndex = index;
 ///          });
 ///        },
 ///      ),
 ///    );
 ///  }
 /// ```
 class FadeThroughTransition extends StatelessWidget {
   /// Creates a [FadeThroughTransition].
   ///
   /// The [animation] and [secondaryAnimation] argument are required and must
   /// not be null.
   const FadeThroughTransition({
     Key? key,
     required this.animation,
     required this.secondaryAnimation,
     this.fillColor,
     this.child,
   }) : super(key: key);

   /// The animation that drives the [child]'s entrance and exit.
   ///
   /// See also:
   ///
   ///  * [TransitionRoute.animate], which is the value given to this property
   ///    when the [FadeThroughTransition] is used as a page transition.
   final Animation<double> animation;

   /// The animation that transitions [child] when new content is pushed on top
   /// of it.
   ///
   /// See also:
   ///
   ///  * [TransitionRoute.secondaryAnimation], which is the value given to this
   //     property when the [FadeThroughTransition] is used as a page transition.
   final Animation<double> secondaryAnimation;

   /// The color to use for the background color during the transition.
   ///
   /// This defaults to the [Theme]'s [ThemeData.canvasColor].
   final Color? fillColor;

   /// The widget below this widget in the tree.
   ///
   /// This widget will transition in and out as driven by [animation] and
   /// [secondaryAnimation].
   final Widget? child;

   @override
   Widget build(BuildContext context) {
     return _ZoomedFadeInFadeOut(
       animation: animation,
       child: Container(
         color: fillColor ?? Theme.of(context).canvasColor,
         child: _ZoomedFadeInFadeOut(
           animation: ReverseAnimation(secondaryAnimation),
           child: child,
         ),
       ),
     );
   }
 }

 class _ZoomedFadeInFadeOut extends StatelessWidget {
   const _ZoomedFadeInFadeOut({Key? key, required this.animation, this.child})
       : super(key: key);

   final Animation<double> animation;
   final Widget? child;

   @override
   Widget build(BuildContext context) {
     return DualTransitionBuilder(
       animation: animation,
       forwardBuilder: (
         BuildContext context,
         Animation<double> animation,
         Widget? child,
       ) {
         return _ZoomedFadeIn(
           animation: animation,
           child: child,
         );
       },
       reverseBuilder: (
         BuildContext context,
         Animation<double> animation,
         Widget? child,
       ) {
         return _FadeOut(
           child: child,
           animation: animation,
         );
       },
       child: child,
     );
   }
 }

 class _ZoomedFadeIn extends StatelessWidget {
   const _ZoomedFadeIn({
     this.child,
     required this.animation,
   });

   final Widget? child;
   final Animation<double> animation;

   static final CurveTween _inCurve = CurveTween(
     curve: const Cubic(0.0, 0.0, 0.2, 1.0),
   );
   static final TweenSequence<double> _scaleIn = TweenSequence<double>(
     <TweenSequenceItem<double>>[
       TweenSequenceItem<double>(
         tween: ConstantTween<double>(0.92),
         weight: 6 / 20,
       ),
       TweenSequenceItem<double>(
         tween: Tween<double>(begin: 0.92, end: 1.0).chain(_inCurve),
         weight: 14 / 20,
       ),
     ],
   );
   static final TweenSequence<double> _fadeInOpacity = TweenSequence<double>(
     <TweenSequenceItem<double>>[
       TweenSequenceItem<double>(
         tween: ConstantTween<double>(0.0),
         weight: 6 / 20,
       ),
       TweenSequenceItem<double>(
         tween: Tween<double>(begin: 0.0, end: 1.0).chain(_inCurve),
         weight: 14 / 20,
       ),
     ],
   );

   @override
   Widget build(BuildContext context) {
     return FadeTransition(
       opacity: _fadeInOpacity.animate(animation),
       child: ScaleTransition(
         scale: _scaleIn.animate(animation),
         child: child,
       ),
     );
   }
 }

 class _FadeOut extends StatelessWidget {
   const _FadeOut({
     this.child,
     required this.animation,
   });

   final Widget? child;
   final Animation<double> animation;

   static final CurveTween _outCurve = CurveTween(
     curve: const Cubic(0.4, 0.0, 1.0, 1.0),
   );
   static final TweenSequence<double> _fadeOutOpacity = TweenSequence<double>(
     <TweenSequenceItem<double>>[
       TweenSequenceItem<double>(
         tween: Tween<double>(begin: 1.0, end: 0.0).chain(_outCurve),
         weight: 6 / 20,
       ),
       TweenSequenceItem<double>(
         tween: ConstantTween<double>(0.0),
         weight: 14 / 20,
       ),
     ],
   );

   @override
   Widget build(BuildContext context) {
     return FadeTransition(
       opacity: _fadeOutOpacity.animate(animation),
       child: child,
     );
   }
 }
	// Copyright 2013 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.

	import 'package:flutter/material.dart';

	/// Used by [PageTransitionsTheme] to define a page route transition animation
	/// in which the outgoing page fades out, then the incoming page fades in and
	/// scale up.
	///
	/// This pattern is recommended for a transition between UI elements that do not
	/// have a strong relationship to one another.
	///
	/// Scale is only applied to incoming elements to emphasize new content over
	/// old.
	///
	/// The following example shows how the FadeThroughPageTransitionsBuilder can
	/// be used in a [PageTransitionsTheme] to change the default transitions
	/// of [MaterialPageRoute]s.
	///
	/// ```dart
	/// MaterialApp(
	/// theme: ThemeData(
	/// pageTransitionsTheme: PageTransitionsTheme(
	/// builders: {
	/// TargetPlatform.android: FadeThroughPageTransitionsBuilder(),
	/// TargetPlatform.iOS: FadeThroughPageTransitionsBuilder(),
	/// },
	/// ),
	/// ),
	/// routes: {
	/// '/': (BuildContext context) {
	/// return Container(
	/// color: Colors.red,
	/// child: Center(
	/// child: TextButton(
	/// child: Text('Push route'),
	/// onPressed: () {
	/// Navigator.of(context).pushNamed('/a');
	/// },
	/// ),
	/// ),
	/// );
	/// },
	/// '/a' : (BuildContext context) {
	/// return Container(
	/// color: Colors.blue,
	/// child: Center(
	/// child: TextButton(
	/// child: Text('Pop route'),
	/// onPressed: () {
	/// Navigator.of(context).pop();
	/// },
	/// ),
	/// ),
	/// );
	/// },
	/// },
	/// );
	/// ```
	class FadeThroughPageTransitionsBuilder extends PageTransitionsBuilder {
	/// Creates a [FadeThroughPageTransitionsBuilder].
	const FadeThroughPageTransitionsBuilder({this.fillColor});

	/// The color to use for the background color during the transition.
	///
	/// This defaults to the [Theme]'s [ThemeData.canvasColor].
	final Color? fillColor;

	@override
	Widget buildTransitions<T>(
	PageRoute<T>? route,
	BuildContext? context,
	Animation<double> animation,
	Animation<double> secondaryAnimation,
	Widget child,
	) {
	return FadeThroughTransition(
	animation: animation,
	secondaryAnimation: secondaryAnimation,
	fillColor: fillColor,
	child: child,
	);
	}
	}

	/// Defines a transition in which outgoing elements fade out, then incoming
	/// elements fade in and scale up.
	///
	/// The fade through pattern provides a transition animation between UI elements
	/// that do not have a strong relationship to one another. As an example, the
	/// [BottomNavigationBar] may use this animation to transition the currently
	/// displayed content when a new [BottomNavigationBarItem] is selected.
	///
	/// Scale is only applied to incoming elements to emphasize new content over
	/// old.
	///
	/// Consider using [FadeThroughPageTransitionsBuilder] within a
	/// [PageTransitionsTheme] if you want to apply this kind of transition to
	/// [MaterialPageRoute] transitions within a Navigator (see
	/// [FadeThroughPageTransitionsBuilder] for some example code). Or use this transition
	/// directly in a [PageTransitionSwitcher.transitionBuilder] to transition
	/// from one widget to another as seen in the following example:
	///
	/// ```dart
	/// int _selectedIndex = 0;
	///
	/// final List<Color> _colors = [Colors.blue, Colors.red, Colors.yellow];
	///
	/// @override
	/// Widget build(BuildContext context) {
	/// return Scaffold(
	/// appBar: AppBar(
	/// title: const Text('Switcher Sample'),
	/// ),
	/// body: PageTransitionSwitcher(
	/// transitionBuilder: (
	/// Widget child,
	/// Animation<double> primaryAnimation,
	/// Animation<double> secondaryAnimation,
	/// ) {
	/// return FadeThroughTransition(
	/// child: child,
	/// animation: primaryAnimation,
	/// secondaryAnimation: secondaryAnimation,
	/// );
	/// },
	/// child: Container(
	/// key: ValueKey<int>(_selectedIndex),
	/// color: _colors[_selectedIndex],
	/// ),
	/// ),
	/// bottomNavigationBar: BottomNavigationBar(
	/// items: const <BottomNavigationBarItem>[
	/// BottomNavigationBarItem(
	/// icon: Icon(Icons.home),
	/// title: Text('Blue'),
	/// ),
	/// BottomNavigationBarItem(
	/// icon: Icon(Icons.business),
	/// title: Text('Red'),
	/// ),
	/// BottomNavigationBarItem(
	/// icon: Icon(Icons.school),
	/// title: Text('Yellow'),
	/// ),
	/// ],
	/// currentIndex: _selectedIndex,
	/// selectedItemColor: Colors.amber[800],
	/// onTap: (int index) {
	/// setState(() {
	/// _selectedIndex = index;
	/// });
	/// },
	/// ),
	/// );
	/// }
	/// ```
	class FadeThroughTransition extends StatelessWidget {
	/// Creates a [FadeThroughTransition].
	///
	/// The [animation] and [secondaryAnimation] argument are required and must
	/// not be null.
	const FadeThroughTransition({
	Key? key,
	required this.animation,
	required this.secondaryAnimation,
	this.fillColor,
	this.child,
	}) : super(key: key);

	/// The animation that drives the [child]'s entrance and exit.
	///
	/// See also:
	///
	/// * [TransitionRoute.animate], which is the value given to this property
	/// when the [FadeThroughTransition] is used as a page transition.
	final Animation<double> animation;

	/// The animation that transitions [child] when new content is pushed on top
	/// of it.
	///
	/// See also:
	///
	/// * [TransitionRoute.secondaryAnimation], which is the value given to this
	// property when the [FadeThroughTransition] is used as a page transition.
	final Animation<double> secondaryAnimation;

	/// The color to use for the background color during the transition.
	///
	/// This defaults to the [Theme]'s [ThemeData.canvasColor].
	final Color? fillColor;

	/// The widget below this widget in the tree.
	///
	/// This widget will transition in and out as driven by [animation] and
	/// [secondaryAnimation].
	final Widget? child;

	@override
	Widget build(BuildContext context) {
	return _ZoomedFadeInFadeOut(
	animation: animation,
	child: Container(
	color: fillColor ?? Theme.of(context).canvasColor,
	child: _ZoomedFadeInFadeOut(
	animation: ReverseAnimation(secondaryAnimation),
	child: child,
	),
	),
	);
	}
	}

	class _ZoomedFadeInFadeOut extends StatelessWidget {
	const _ZoomedFadeInFadeOut({Key? key, required this.animation, this.child})
	: super(key: key);

	final Animation<double> animation;
	final Widget? child;

	@override
	Widget build(BuildContext context) {
	return DualTransitionBuilder(
	animation: animation,
	forwardBuilder: (
	BuildContext context,
	Animation<double> animation,
	Widget? child,
	) {
	return _ZoomedFadeIn(
	animation: animation,
	child: child,
	);
	},
	reverseBuilder: (
	BuildContext context,
	Animation<double> animation,
	Widget? child,
	) {
	return _FadeOut(
	child: child,
	animation: animation,
	);
	},
	child: child,
	);
	}
	}

	class _ZoomedFadeIn extends StatelessWidget {
	const _ZoomedFadeIn({
	this.child,
	required this.animation,
	});

	final Widget? child;
	final Animation<double> animation;

	static final CurveTween _inCurve = CurveTween(
	curve: const Cubic(0.0, 0.0, 0.2, 1.0),
	);
	static final TweenSequence<double> _scaleIn = TweenSequence<double>(
	<TweenSequenceItem<double>>[
	TweenSequenceItem<double>(
	tween: ConstantTween<double>(0.92),
	weight: 6 / 20,
	),
	TweenSequenceItem<double>(
	tween: Tween<double>(begin: 0.92, end: 1.0).chain(_inCurve),
	weight: 14 / 20,
	),
	],
	);
	static final TweenSequence<double> _fadeInOpacity = TweenSequence<double>(
	<TweenSequenceItem<double>>[
	TweenSequenceItem<double>(
	tween: ConstantTween<double>(0.0),
	weight: 6 / 20,
	),
	TweenSequenceItem<double>(
	tween: Tween<double>(begin: 0.0, end: 1.0).chain(_inCurve),
	weight: 14 / 20,
	),
	],
	);

	@override
	Widget build(BuildContext context) {
	return FadeTransition(
	opacity: _fadeInOpacity.animate(animation),
	child: ScaleTransition(
	scale: _scaleIn.animate(animation),
	child: child,
	),
	);
	}
	}

	class _FadeOut extends StatelessWidget {
	const _FadeOut({
	this.child,
	required this.animation,
	});

	final Widget? child;
	final Animation<double> animation;

	static final CurveTween _outCurve = CurveTween(
	curve: const Cubic(0.4, 0.0, 1.0, 1.0),
	);
	static final TweenSequence<double> _fadeOutOpacity = TweenSequence<double>(
	<TweenSequenceItem<double>>[
	TweenSequenceItem<double>(
	tween: Tween<double>(begin: 1.0, end: 0.0).chain(_outCurve),
	weight: 6 / 20,
	),
	TweenSequenceItem<double>(
	tween: ConstantTween<double>(0.0),
	weight: 14 / 20,
	),
	],
	);

	@override
	Widget build(BuildContext context) {
	return FadeTransition(
	opacity: _fadeOutOpacity.animate(animation),
	child: child,
	);
	}
	}