| // 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 'dart:typed_data'; |
| import 'dart:ui'; |
| |
| import 'package:flutter/material.dart'; |
| |
| class DrawPointsPage extends StatefulWidget { |
| const DrawPointsPage({super.key}); |
| |
| @override |
| State<DrawPointsPage> createState() => _DrawPointsPageState(); |
| } |
| |
| class _DrawPointsPageState extends State<DrawPointsPage> with SingleTickerProviderStateMixin { |
| late final AnimationController controller; |
| double tick = 0.0; |
| |
| @override |
| void initState() { |
| super.initState(); |
| controller = AnimationController(vsync: this, duration: const Duration(hours: 1)); |
| controller.addListener(() { |
| setState(() { |
| tick += 1; |
| }); |
| }); |
| controller.forward(from: 0); |
| } |
| |
| @override |
| void dispose() { |
| controller.dispose(); |
| super.dispose(); |
| } |
| |
| |
| @override |
| Widget build(BuildContext context) { |
| return CustomPaint( |
| size: const Size(500, 500), |
| painter: PointsPainter(tick), |
| child: Container(), |
| ); |
| } |
| } |
| |
| class PointsPainter extends CustomPainter { |
| PointsPainter(this.tick); |
| |
| final double tick; |
| |
| final Float32List data = Float32List(8000); |
| |
| static const List<Color> kColors = <Color>[ |
| Colors.red, |
| Colors.blue, |
| Colors.green, |
| Colors.yellow, |
| Colors.orange, |
| Colors.purple, |
| Colors.pink, |
| Colors.deepPurple, |
| ]; |
| |
| @override |
| void paint(Canvas canvas, Size size) { |
| if (size.width == 0) { |
| return; |
| } |
| canvas.drawPaint(Paint()..color = Colors.white); |
| for (int i = 0; i < 8; i++) { |
| final double x = ((size.width / (i + 1)) + tick) % size.width; |
| for (int j = 0; j < data.length; j += 2) { |
| data[j] = x; |
| data[j + 1] = (size.height / (j + 1)) + 200; |
| } |
| final Paint paint = Paint() |
| ..color = kColors[i] |
| ..strokeWidth = 5 |
| ..strokeCap = StrokeCap.round |
| ..style = PaintingStyle.stroke; |
| canvas.drawRawPoints(PointMode.points, data, paint); |
| } |
| } |
| |
| @override |
| bool shouldRepaint(covariant CustomPainter oldDelegate) { |
| return true; |
| } |
| } |