| // 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. |
| |
| // Flutter code sample for [Curve2D]. |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| class MyApp extends StatelessWidget { |
| const MyApp({super.key}); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return const MaterialApp( |
| title: _title, |
| home: MyStatelessWidget(), |
| ); |
| } |
| } |
| |
| // This is the path that the child will follow. It's a CatmullRomSpline so |
| // that the coordinates can be specified that it must pass through. If the |
| // tension is set to 1.0, it will linearly interpolate between those points, |
| // instead of interpolating smoothly. |
| final CatmullRomSpline path = CatmullRomSpline( |
| const <Offset>[ |
| Offset(0.05, 0.75), |
| Offset(0.18, 0.23), |
| Offset(0.32, 0.04), |
| Offset(0.73, 0.5), |
| Offset(0.42, 0.74), |
| Offset(0.73, 0.01), |
| Offset(0.93, 0.93), |
| Offset(0.05, 0.75), |
| ], |
| startHandle: const Offset(0.93, 0.93), |
| endHandle: const Offset(0.18, 0.23), |
| ); |
| |
| class FollowCurve2D extends StatefulWidget { |
| const FollowCurve2D({ |
| super.key, |
| required this.path, |
| this.curve = Curves.easeInOut, |
| required this.child, |
| this.duration = const Duration(seconds: 1), |
| }); |
| |
| final Curve2D path; |
| final Curve curve; |
| final Duration duration; |
| final Widget child; |
| |
| @override |
| State<FollowCurve2D> createState() => _FollowCurve2DState(); |
| } |
| |
| class _FollowCurve2DState extends State<FollowCurve2D> |
| with TickerProviderStateMixin { |
| // The animation controller for this animation. |
| late AnimationController controller; |
| // The animation that will be used to apply the widget's animation curve. |
| late Animation<double> animation; |
| |
| @override |
| void initState() { |
| super.initState(); |
| controller = AnimationController(duration: widget.duration, vsync: this); |
| animation = CurvedAnimation(parent: controller, curve: widget.curve); |
| // Have the controller repeat indefinitely. If you want it to "bounce" back |
| // and forth, set the reverse parameter to true. |
| controller.repeat(); |
| controller.addListener(() => setState(() {})); |
| } |
| |
| @override |
| void dispose() { |
| // Always have to dispose of animation controllers when done. |
| controller.dispose(); |
| super.dispose(); |
| } |
| |
| @override |
| Widget build(BuildContext context) { |
| // Scale the path values to match the -1.0 to 1.0 domain of the Alignment widget. |
| final Offset position = |
| widget.path.transform(animation.value) * 2.0 - const Offset(1.0, 1.0); |
| return Align( |
| alignment: Alignment(position.dx, position.dy), |
| child: widget.child, |
| ); |
| } |
| } |
| |
| class MyStatelessWidget extends StatelessWidget { |
| const MyStatelessWidget({super.key}); |
| |
| @override |
| Widget build(BuildContext context) { |
| return Container( |
| color: Colors.white, |
| alignment: Alignment.center, |
| child: FollowCurve2D( |
| path: path, |
| duration: const Duration(seconds: 3), |
| child: CircleAvatar( |
| backgroundColor: Colors.yellow, |
| child: DefaultTextStyle( |
| style: Theme.of(context).textTheme.titleLarge!, |
| child: const Text('B'), // Buzz, buzz! |
| ), |
| ), |
| ), |
| ); |
| } |
| } |