97 lines
2.4 KiB
Dart
97 lines
2.4 KiB
Dart
import 'package:flutter/cupertino.dart';
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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 2020-03-19
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/// contact me by email 1981462002@qq.com
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/// 说明: 纸
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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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child: CustomPaint(
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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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late Paint _gridPint; // 画笔
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final double step = 20; // 小格边长
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final double strokeWidth = .5; // 线宽
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final Color color = Colors.grey; // 线颜色
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PaperPainter() {
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_gridPint = Paint()
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..style = PaintingStyle.stroke
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..strokeWidth = strokeWidth
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..color = color;
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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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_drawGrid(canvas, size);
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_drawPart(canvas);
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}
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void _drawPart(Canvas canvas) {
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var paint = Paint()
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..style = PaintingStyle.fill
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..color = Colors.blue;
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canvas.drawCircle(Offset(0, 0), 50, paint);
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canvas.drawLine(
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Offset(20, 20),
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Offset(50, 50),
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paint
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..color = Colors.red
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..strokeWidth = 5
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..strokeCap = StrokeCap.round
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..style = PaintingStyle.stroke);
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}
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void _drawGrid(Canvas canvas, Size size) {
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_drawBottomRight(canvas, size);
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canvas.save();
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canvas.scale(1, -1); //沿x轴镜像
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_drawBottomRight(canvas, size);
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canvas.restore();
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canvas.save();
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canvas.scale(-1, 1); //沿y轴镜像
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_drawBottomRight(canvas, size);
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canvas.restore();
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canvas.save();
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canvas.scale(-1, -1); //沿原点镜像
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_drawBottomRight(canvas, size);
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canvas.restore();
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}
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void _drawBottomRight(Canvas canvas, Size size) {
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canvas.save();
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for (int i = 0; i < size.height / 2 / step; i++) {
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canvas.drawLine(Offset(0, 0), Offset(size.width / 2, 0), _gridPint);
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canvas.translate(0, step);
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}
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canvas.restore();
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canvas.save();
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for (int i = 0; i < size.width / 2 / step; i++) {
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canvas.drawLine(Offset(0, 0), Offset(0, size.height / 2), _gridPint);
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canvas.translate(step , 0);
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}
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canvas.restore();
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}
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@override
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bool shouldRepaint(CustomPainter oldDelegate) => true;
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}
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