forked from lxm_flutter/FlutterUnit
97 lines
2.4 KiB
Dart
97 lines
2.4 KiB
Dart
import 'dart:math';
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import 'package:flutter/material.dart';
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import 'dart:ui' as ui;
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// import '../coordinate_pro.dart';
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/// create by 张风捷特烈 on 2020/5/1
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/// contact me by email 1981462002@qq.com
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/// 说明:
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class DrawPathFun extends StatelessWidget {
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const DrawPathFun({Key? key}) : super(key: key);
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@override
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Widget build(BuildContext context) {
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double size = MediaQuery.of(context).size.shortestSide;
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return Container(
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color: Colors.white,
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child: CustomPaint(
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size: Size(size, size),
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// 使用CustomPaint
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painter: PaperPainter(),
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),
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);
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}
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}
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class PaperPainter extends CustomPainter {
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// final Coordinate coordinate = Coordinate();
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final List<Offset> points = [];
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final double step = 6;
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final double min = -240;
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final double max = 240;
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final List<Color> colors = const[
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Color(0xFFF60C0C),
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Color(0xFFF3B913),
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Color(0xFFE7F716),
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Color(0xFF3DF30B),
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Color(0xFF0DF6EF),
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Color(0xFF0829FB),
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Color(0xFFB709F4),
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];
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void initPoints() {
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for (double x = min; x < max; x += step) {
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points.add(Offset(x, f(x)));
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}
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points.add(Offset(max, f(max)));
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points.add(Offset(max, f(max)));
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}
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void initPointsWithPolar() {
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for (double x = min; x < max; x += step) {
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double thta = (pi / 180 * x); // 角度转化为弧度
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var p = f(thta);
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points.add(Offset(p * cos(thta), p * sin(thta)));
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}
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}
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double f(double thta) {
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double p =
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40 * (pow(e, cos(thta)) - 2 * cos(4 * thta) + pow(sin(thta / 12), 5));
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return p;
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}
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@override
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void paint(Canvas canvas, Size size) {
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canvas.translate(size.width / 2, size.height / 2);
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initPointsWithPolar();
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Paint paint = Paint()
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..color = Colors.red
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..strokeWidth = 1.5
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..style = PaintingStyle.stroke;
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var pos = [1.0 / 7, 2.0 / 7, 3.0 / 7, 4.0 / 7, 5.0 / 7, 6.0 / 7, 1.0];
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paint.shader = ui.Gradient.linear(
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const Offset(0, 0), const Offset(100, 0), colors, pos, TileMode.mirror);
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Offset p1 = points[0];
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Path path = Path()..moveTo(p1.dx, p1.dy);
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for (var i = 1; i < points.length - 1; i++) {
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double xc = (points[i].dx + points[i + 1].dx) / 2;
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double yc = (points[i].dy + points[i + 1].dy) / 2;
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Offset p2 = points[i];
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path.quadraticBezierTo(p2.dx, p2.dy, xc, yc);
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}
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canvas.drawPath(path, paint);
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}
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@override
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bool shouldRepaint(CustomPainter oldDelegate) => false;
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}
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