books

packages/idraw/lib/p14/s04.dart

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+import 'dart:math';
+import 'dart:ui';
+
+import 'package:flutter/material.dart';
+import 'dart:ui' as ui;
+
+import '../components/coordinate_pro.dart';
+import 'touch_info.dart';
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+class Paper extends StatefulWidget {
+  const Paper({super.key});
+
+  @override
+  _PaperState createState() => _PaperState();
+}
+
+class _PaperState extends State<Paper> {
+  final TouchInfo touchInfo = TouchInfo();
+
+  //单位圆(即半径为1)控制线长
+  final rate = 0.551915024494;
+  double _radius = 150;
+
+  @override
+  void initState() {
+    super.initState();
+    touchInfo.setPoints(_initPoints());
+  }
+
+  @override
+  void dispose() {
+    touchInfo.dispose();
+    super.dispose();
+  }
+
+  List<Offset> _initPoints() {
+    final List<Offset> pos = [];
+    //第一段线
+    pos.add(Offset(0, rate) * _radius);
+    pos.add(Offset(1 - rate, 1) * _radius);
+    pos.add(Offset(1, 1) * _radius);
+    //第二段线
+    pos.add(Offset(1 + rate, 1) * _radius);
+    pos.add(Offset(2, rate) * _radius);
+    pos.add(Offset(2, 0) * _radius);
+    //第三段线
+    pos.add(Offset(2, -rate) * _radius);
+    pos.add(Offset(1 + rate, -1) * _radius);
+    pos.add(Offset(1, -1) * _radius);
+    //第四段线
+    pos.add(Offset(1 - rate, -1) * _radius);
+    pos.add(Offset(0, -rate) * _radius);
+    pos.add(Offset(0, 0));
+    return pos;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return LayoutBuilder(
+      builder:(_,cts)=> GestureDetector(
+        onPanDown: (details)=>_onPanDown(details,cts.biggest),
+        onPanUpdate: (details)=>_onPanUpdate(details,cts.biggest),
+        child: Container(
+          color: Colors.white,
+          child: CustomPaint(
+            painter: PaperPainter(repaint: touchInfo),
+          ),
+        ),
+      ),
+    );
+  }
+
+  void _onPanDown(DragDownDetails details,Size size) {
+    print("=====${details}===========${touchInfo.points.length}}");
+    if (touchInfo.points.length < 4) {
+      touchInfo.addPoint(details.localPosition);
+    } else {
+      judgeZone(details.localPosition,size);
+    }
+  }
+
+  void _onPanUpdate(DragUpdateDetails details,Size size) {
+    judgeZone(details.localPosition,size, update: true);
+  }
+
+  ///判断出是否在某点的半径为r圆范围内
+  bool judgeCircleArea(Offset src, Offset dst, double r) =>
+      (src - dst).distance <= r;
+
+  //判断哪个点被选中
+  void judgeZone(Offset src, Size size,{bool update = false}) {
+    src= src.translate(-size.width/2, -size.height/2);
+    for (int i = 0; i < touchInfo.points.length; i++) {
+      if (judgeCircleArea(src, touchInfo.points[i], 15)) {
+        touchInfo.selectIndex = i;
+        if (update) {
+          touchInfo.updatePoint(i, src);
+        }
+      }
+    }
+  }
+}
+
+class PaperPainter extends CustomPainter {
+  final Coordinate coordinate = Coordinate();
+
+  Paint _helpPaint = Paint()
+    ..color = Colors.purple
+    ..style = PaintingStyle.stroke
+    ..strokeCap = StrokeCap.round;
+
+  final TouchInfo repaint;
+
+  PaperPainter({required this.repaint}) : super(repaint: repaint);
+  List<Offset> pos = [];
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    pos = repaint.points;
+
+    Path path = Path();
+    Paint paint = Paint()
+      ..color = Colors.orange
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 2;
+    path.moveTo(0, 0);
+    for (int i = 0; i < pos.length / 3; i++) {
+      path.cubicTo(pos[3 * i + 0].dx, pos[3 * i + 0].dy, pos[3 * i + 1].dx,
+          pos[3 * i + 1].dy, pos[3 * i + 2].dx, pos[3 * i + 2].dy);
+    }
+
+    canvas.drawPath(path, paint);
+    _drawHelp(canvas);
+    _drawSelectPos(canvas, size);
+  }
+
+  void _drawHelp(Canvas canvas) {
+
+    _helpPaint..strokeWidth = 1..color=Colors.purple;
+    canvas.drawLine(pos[0], pos[11], _helpPaint);
+    canvas.drawLine(pos[1], pos[2], _helpPaint);
+    canvas.drawLine(pos[2], pos[3], _helpPaint);
+    canvas.drawLine(pos[4], pos[5], _helpPaint);
+    canvas.drawLine(pos[5], pos[6], _helpPaint);
+    canvas.drawLine(pos[7], pos[8], _helpPaint);
+    canvas.drawLine(pos[8], pos[9], _helpPaint);
+    canvas.drawLine(pos[10], pos[11], _helpPaint);
+    canvas.drawLine(pos[11], pos[0], _helpPaint);
+    canvas.drawPoints(PointMode.points, pos, _helpPaint..strokeWidth = 8);
+  }
+
+  void _drawSelectPos(Canvas canvas, Size size) {
+    Offset? selectPos = repaint.selectPoint;
+    if (selectPos == null) return;
+
+    canvas.drawCircle(selectPos, 10,
+        _helpPaint..color = Colors.green..strokeWidth = 2);
+  }
+
+  @override
+  bool shouldRepaint(PaperPainter oldDelegate) =>
+      oldDelegate.repaint != repaint;
+}