// 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. import 'package:flutter/material.dart'; /// Flutter code sample for [Curve2D]. void main() => runApp(const Curve2DExampleApp()); class Curve2DExampleApp extends StatelessWidget { const Curve2DExampleApp({super.key}); @override Widget build(BuildContext context) { return const MaterialApp( home: Curve2DExample(), ); } } // 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 Curve2DExample extends StatelessWidget { const Curve2DExample({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! ), ), ), ); } }