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toly
301
packages/idraw/lib/p19/s01.dart
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301
packages/idraw/lib/p19/s01.dart
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import 'dart:math';
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import 'dart:ui' as ui;
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import 'package:flutter/material.dart';
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import 'package:flutter/services.dart';
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/// create by 张风捷特烈 on 2020/11/5
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/// contact me by email 1981462002@qq.com
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/// 说明:
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class Paper extends StatelessWidget {
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const Paper({super.key});
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@override
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Widget build(BuildContext context) {
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return Container(
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color: Colors.white,
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alignment: Alignment.center,
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child: LayoutBuilder(
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builder: (ctx, constraints) => World(size: constraints.biggest),
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),
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);
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}
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}
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class World extends StatefulWidget {
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final Size size;
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const World({Key? key, required this.size}) : super(key: key);
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@override
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_WorldState createState() => _WorldState();
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}
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class _WorldState extends State<World> with SingleTickerProviderStateMixin {
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late AnimationController _controller;
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ParticleManage pm = ParticleManage();
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Random random = Random();
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@override
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void initState() {
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super.initState();
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loadImageFromAssets("assets/images/sword.png");
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pm.size = widget.size;
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initParticles();
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_controller = AnimationController(
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duration: const Duration(seconds: 1),
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vsync: this,
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)
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..addListener(pm.tick)
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..repeat();
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}
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@override
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void dispose() {
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_controller.dispose();
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super.dispose();
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}
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theWorld() {
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if (_controller.isAnimating) {
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_controller.stop();
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} else {
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_controller.repeat();
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}
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}
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@override
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Widget build(BuildContext context) {
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return Stack(
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children: [
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Container(
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width: widget.size.width,
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height: widget.size.height,
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child: Image.asset(
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'assets/images/bg.jpeg',
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fit: BoxFit.cover,
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)),
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GestureDetector(
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onTap: theWorld,
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child: CustomPaint(
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size: pm.size,
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painter: WorldRender(
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manage: pm,
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),
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),
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),
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],
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);
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}
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//读取 assets 中的图片
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void loadImageFromAssets(String path) async {
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ByteData data = await rootBundle.load(path);
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pm.setImage(await decodeImageFromList(data.buffer.asUint8List()));
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}
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void initParticles() {
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for (int i = 0; i < 60; i++) {
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Particle particle = Particle(
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x: pm.size.width / 60 * i,
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y: 0,
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vx: 1 * random.nextDouble() * pow(-1, random.nextInt(20)),
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vy: 4 * random.nextDouble() + 1);
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pm.particles.add(particle);
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}
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}
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}
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class WorldRender extends CustomPainter {
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final ParticleManage manage;
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Paint fillPaint = Paint()
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..colorFilter = ColorFilter.matrix(<double>[
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1,
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0,
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0,
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0,
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0,
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0,
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1,
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0,
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0,
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0,
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0,
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0,
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1,
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0,
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0,
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0,
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0,
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0,
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0.4,
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0,
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]);
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Paint stokePaint = Paint()
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..strokeWidth = 0.5
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..style = PaintingStyle.stroke;
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WorldRender({required this.manage}) : super(repaint: manage);
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@override
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void paint(Canvas canvas, Size size) {
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if (manage.image == null) return;
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// canvas.drawRect(Offset.zero&size, stokePaint);
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manage.particles.forEach((particle) {
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drawParticle(canvas, particle);
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});
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}
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void drawParticle(Canvas canvas, Particle particle) {
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fillPaint.color = particle.color;
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if (manage.image == null) return;
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canvas.save();
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canvas.translate(particle.x, particle.y);
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var dis = sqrt(particle.vy * particle.vy + particle.vx * particle.vx);
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canvas.rotate(acos(particle.vx / dis) + pi + pi / 2);
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canvas.drawImageRect(
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manage.image!,
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Rect.fromLTWH(
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0, 0, manage.image!.width * 1.0, manage.image!.height * 1.0),
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Rect.fromLTWH(
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0, 0, manage.image!.width * 0.18, manage.image!.height * 0.18),
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fillPaint);
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canvas.restore();
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}
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@override
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bool shouldRepaint(covariant WorldRender oldDelegate) =>
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oldDelegate.manage != manage;
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}
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class ParticleManage with ChangeNotifier {
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List<Particle> particles = [];
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Random random = Random();
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ui.Image? image;
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void setImage(ui.Image image) {
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this.image = image;
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notifyListeners();
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}
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Size size;
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ParticleManage({this.size = Size.zero});
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void setParticles(List<Particle> particles) {
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this.particles = particles;
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}
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void addParticle(Particle particle) {
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particles.add(particle);
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notifyListeners();
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}
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void tick() {
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for (int i = 0; i < particles.length; i++) {
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doUpdate(particles[i]);
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}
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notifyListeners();
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}
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void doUpdate(Particle p) {
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p.vy += p.ay; // y加速度变化
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p.vx += p.ax; // x加速度变化
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p.x += p.vx;
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p.y += p.vy;
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if (p.x > size.width) {
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p.x = size.width;
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p.vx = -p.vx;
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}
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if (p.x < 0) {
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p.x = 0;
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p.vx = -p.vx;
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}
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if (p.y > size.height) {
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p.y = 0;
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}
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}
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void reset() {
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particles.forEach((p) {
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p.x = 0;
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});
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notifyListeners();
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}
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Color randomRGB({
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int limitR = 0,
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int limitG = 0,
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int limitB = 0,
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}) {
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var r = limitR + random.nextInt(256 - limitR); //红值
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var g = limitG + random.nextInt(256 - limitG); //绿值
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var b = limitB + random.nextInt(256 - limitB); //蓝值
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return Color.fromARGB(255, r, g, b); //生成argb模式的颜色
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}
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}
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class Particle {
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/// x 位移.
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double x;
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/// y 位移.
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double y;
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/// 粒子水平速度.
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double vx;
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// 粒子水平加速度
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double ax;
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// 粒子竖直加速度
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double ay;
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///粒子竖直速度.
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double vy;
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/// 粒子大小.
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double size;
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/// 粒子颜色.
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Color color;
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Particle({
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this.x = 0,
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this.y = 0,
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this.ax = 0,
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this.ay = 0,
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this.vx = 0,
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this.vy = 0,
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this.size = 0,
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this.color = Colors.black,
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});
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Particle copyWith(
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{double? x,
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double? y,
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double? ax,
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double? ay,
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double? vx,
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double? vy,
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double? size,
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Color? color}) =>
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Particle(
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x: x ?? this.x,
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y: y ?? this.y,
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ax: ax ?? this.ax,
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ay: ay ?? this.ay,
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vx: vx ?? this.vx,
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vy: vy ?? this.vy,
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size: size ?? this.size,
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color: color ?? this.color);
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}
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