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July 24, 2024 18:11
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Circular List - by Simon Lightfoot - Humpday Q&A :: 26th June 2024 #Flutter #Dart https://www.youtube.com/watch?v=mMv9wRcKZrw
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| // MIT License | |
| // | |
| // Copyright (c) 2024 Simon Lightfoot | |
| // | |
| // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| // of this software and associated documentation files (the "Software"), to deal | |
| // in the Software without restriction, including without limitation the rights | |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| // copies of the Software, and to permit persons to whom the Software is | |
| // furnished to do so, subject to the following conditions: | |
| // | |
| // The above copyright notice and this permission notice shall be included in all | |
| // copies or substantial portions of the Software. | |
| // | |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| // SOFTWARE. | |
| // | |
| import 'dart:async'; | |
| import 'dart:math' as math; | |
| import 'package:flutter/material.dart'; | |
| import 'package:flutter/rendering.dart'; | |
| void main() { | |
| runApp(const App()); | |
| } | |
| class App extends StatelessWidget { | |
| const App({super.key}); | |
| @override | |
| Widget build(BuildContext context) { | |
| return const MaterialApp( | |
| debugShowCheckedModeBanner: false, | |
| home: Home(), | |
| ); | |
| } | |
| } | |
| class Home extends StatefulWidget { | |
| const Home({super.key}); | |
| @override | |
| State<Home> createState() => _HomeState(); | |
| } | |
| class _HomeState extends State<Home> { | |
| @override | |
| Widget build(BuildContext context) { | |
| return const Material( | |
| child: SafeArea( | |
| child: CircularList(), | |
| ), | |
| ); | |
| } | |
| } | |
| class CircularList extends StatelessWidget { | |
| const CircularList({ | |
| super.key, | |
| }); | |
| @override | |
| Widget build(BuildContext context) { | |
| return Scrollable( | |
| controller: PrimaryScrollController.maybeOf(context), | |
| axisDirection: AxisDirection.right, | |
| physics: const BouncingScrollPhysics(), | |
| viewportBuilder: (BuildContext context, ViewportOffset position) { | |
| return Flow( | |
| delegate: CircularScrollDelegate( | |
| position: position, | |
| size: const Size.square(80.0), | |
| ), | |
| children: [ | |
| for (int i = 0; i < Colors.accents.length; i++) // | |
| ColoredBox( | |
| color: Colors.accents[i], | |
| child: Center(child: Text('Item #$i')), | |
| ), | |
| ], | |
| ); | |
| }, | |
| ); | |
| } | |
| } | |
| class CircularScrollDelegate extends FlowDelegate { | |
| CircularScrollDelegate({ | |
| required this.position, | |
| required this.size, | |
| }) : super(repaint: position); | |
| final ViewportOffset position; | |
| final Size size; | |
| @override | |
| bool shouldRepaint(covariant CircularScrollDelegate oldDelegate) { | |
| return position != oldDelegate.position; | |
| } | |
| @override | |
| BoxConstraints getConstraintsForChild(int i, BoxConstraints constraints) { | |
| return BoxConstraints.tight(size); | |
| } | |
| @override | |
| void paintChildren(FlowPaintingContext context) { | |
| scheduleMicrotask(() { | |
| position.applyViewportDimension(context.size.width); | |
| position.applyContentDimensions( | |
| 0.0, | |
| (size.width * context.childCount) - context.size.width, | |
| ); | |
| }); | |
| final centerX = (context.size.width - size.width) / 2; | |
| final centerY = (context.size.height - size.height) / 2; | |
| final phase = position.pixels / size.width; | |
| final rx = (context.size.width - size.width) / 2; | |
| final ry = (context.size.height - size.height) / 2; | |
| for (int i = 0; i < context.childCount; i++) { | |
| final e = i / context.childCount; | |
| final x = math.sin(e * math.pi * 2 - phase) * rx; | |
| final y = math.cos(e * math.pi * 2 - phase) * ry; | |
| // if (y < 0) { | |
| // continue; | |
| // } | |
| context.paintChild( | |
| i, | |
| transform: Matrix4.translationValues( | |
| centerX + x, | |
| centerY + y, | |
| 0.0, | |
| ), | |
| ); | |
| } | |
| } | |
| } |
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