books

assets/draw/p06/p06.dart

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+export 'p06_page.dart';

assets/draw/p06/p06_page.dart

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+import 'package:flutter/material.dart';
+
+import 'package:idraw/components/demo_shower.dart';
+import 's01.dart' as s1;
+import 's02.dart' as s2;
+import 's03.dart' as s3;
+import 's04.dart' as s4;
+import 's05.dart' as s5;
+import 's06.dart' as s6;
+
+class P06Page extends StatelessWidget {
+  const P06Page({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const DemoShower(
+      srcCodeDir: 'draw/p06',
+      demos:  [
+        s1.Paper(),
+        s2.Paper(),
+        s3.Paper(),
+        s4.Paper(),
+        s5.Paper(),
+        s6.Paper(),
+      ],
+    );
+  }
+}

assets/draw/p06/s01.dart

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+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate.dart';
+
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+class Paper extends StatelessWidget {
+  const Paper({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(),
+      ),
+    );
+  }
+}
+
+class PaperPainter extends CustomPainter {
+
+
+  final Coordinate coordinate = Coordinate();
+  PaperPainter();
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+
+    Paint paint = Paint()
+      ..color = Colors.purpleAccent
+      ..strokeWidth = 2
+      ..style = PaintingStyle.stroke;
+
+    path
+      ..lineTo(100, 100)
+      ..relativeLineTo(0, -50)
+      ..close();
+
+    canvas.drawPath(path, paint);
+    canvas.drawPath(path.shift(Offset(100, 0)), paint);
+    canvas.drawPath(path.shift(Offset(200, 0)), paint);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p06/s02.dart

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+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+class Paper extends StatelessWidget {
+  const Paper({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(),
+      ),
+    );
+  }
+}
+
+class PaperPainter extends CustomPainter {
+  final Coordinate coordinate = Coordinate();
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+    Paint paint = Paint()
+      ..color = Colors.purple
+      ..style = PaintingStyle.fill;
+
+    path
+      ..relativeMoveTo(0, 0)
+      ..relativeLineTo(-30, 120)
+      ..relativeLineTo(30, -30)
+      ..relativeLineTo(30, 30)
+      ..close();
+
+    canvas.drawPath(path, paint);
+
+    print(path.contains(Offset(20, 20)));
+    print(path.contains(Offset(0, 20)));
+
+    Rect bounds = path.getBounds();
+    canvas.drawRect(
+        bounds,
+        Paint()
+          ..color = Colors.orange
+          ..style = PaintingStyle.stroke
+          ..strokeWidth = 1);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p06/s03.dart

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+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+
+class Paper extends StatelessWidget {
+  const Paper({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(),
+      ),
+    );
+  }
+}
+
+class PaperPainter extends CustomPainter {
+
+
+  final Coordinate coordinate = Coordinate();
+
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+    Paint paint = Paint()
+      ..color = Colors.purple
+      ..style = PaintingStyle.fill;
+    path
+      ..relativeMoveTo(0, 0)
+      ..relativeLineTo(-30, 120)
+      ..relativeLineTo(30, -30)
+      ..relativeLineTo( 30,30)
+      ..close();
+
+    for(int i=0;i<8;i++){
+      canvas.drawPath(path.transform(Matrix4.rotationZ(i*pi/4).storage), paint);
+    }
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p06/s04.dart

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+
+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate.dart';
+
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+class Paper extends StatelessWidget {
+  const Paper({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(),
+      ),
+    );
+  }
+}
+
+class PaperPainter extends CustomPainter {
+
+
+  final Coordinate coordinate= Coordinate();
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+    Paint paint = Paint();
+    paint
+      ..color = Colors.purple
+      ..style = PaintingStyle.fill;
+    path
+      ..relativeMoveTo(0, 0)
+      ..relativeLineTo(-30, 120)
+      ..relativeLineTo(30, -30)
+      ..relativeLineTo( 30,30)
+      ..close();
+
+
+    var pathOval =Path()..addOval(Rect.fromCenter(center: Offset(0, 0),width: 60,height: 60));
+    canvas.drawPath(Path.combine(PathOperation.difference, path, pathOval), paint);
+
+    canvas.translate(120, 0);
+    canvas.drawPath(Path.combine(PathOperation.intersect, path, pathOval), paint);
+
+    canvas.translate(120, 0);
+    canvas.drawPath(Path.combine(PathOperation.union, path, pathOval), paint);
+
+    canvas.translate(-120*3.0, 0);
+    canvas.drawPath(Path.combine(PathOperation.reverseDifference, path, pathOval), paint);
+
+    canvas.translate(-120, 0);
+    canvas.drawPath(Path.combine(PathOperation.xor, path, pathOval), paint);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p06/s05.dart

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+
+import 'dart:ui';
+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate.dart';
+
+
+
+/// create by 张风捷特烈 on 2020/5/1
+/// contact me by email 1981462002@qq.com
+/// 说明:
+
+class Paper extends StatelessWidget{
+  const Paper({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(),
+      ),
+    );
+  }
+
+}
+
+class PaperPainter extends CustomPainter {
+  final Coordinate coordinate = Coordinate();
+
+
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Paint paint = Paint()
+      ..color = Colors.purple
+      ..strokeWidth = 1
+      ..style = PaintingStyle.stroke;
+
+    Path path = Path();
+    path
+      ..relativeMoveTo(0, 0)
+      ..relativeLineTo(-30, 120)
+      ..relativeLineTo(30, -30)
+      ..relativeLineTo(30, 30)
+      ..close();
+
+    path.addOval(Rect.fromCenter(center: Offset.zero, width: 50, height: 50));
+
+    PathMetrics pms = path.computeMetrics();
+    pms.forEach((pm) {
+      print(
+          "---length:-${pm.length}----contourIndex:-${pm.contourIndex}----contourIndex:-${pm.isClosed}----");
+
+      Tangent? tangent = pm.getTangentForOffset(pm.length * 0.5);
+      if(tangent==null) return;
+      print(
+          "---position:-${tangent.position}----angle:-${tangent.angle}----vector:-${tangent.vector}----");
+
+      canvas.drawCircle(
+          tangent.position, 5, Paint()..color = Colors.deepOrange);
+    });
+
+    canvas.drawPath(path, paint);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p06/s06.dart

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+import 'dart:ui';
+import 'package:flutter/material.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> with SingleTickerProviderStateMixin {
+  late AnimationController _ctrl;
+  double progress = 0.0;
+
+  @override
+  void initState() {
+    super.initState();
+    _ctrl = AnimationController(
+        duration: Duration(seconds: 3), vsync: this)
+      ..forward();
+  }
+
+  @override
+  void dispose() {
+    _ctrl.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      child: CustomPaint(
+        // 使用CustomPaint
+        painter: PaperPainter(progress: _ctrl),
+      ),
+    );
+  }
+}
+
+class PaperPainter extends CustomPainter {
+  final Animation<double> progress;
+
+  PaperPainter({required this.progress}) : super(repaint: progress);
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Paint paint = Paint()
+      ..color = Colors.purple
+      ..strokeWidth = 1
+      ..style = PaintingStyle.stroke;
+
+    Path path = Path();
+    path
+      ..relativeMoveTo(0, 0)
+      ..relativeLineTo(-30, 120)
+      ..relativeLineTo(30, -30)
+      ..relativeLineTo(30, 30)
+      ..close();
+
+    path.addOval(Rect.fromCenter(center: Offset.zero, width: 50, height: 50));
+
+    PathMetrics pms = path.computeMetrics();
+    for (PathMetric pm in pms) {
+      Tangent? tangent = pm.getTangentForOffset(pm.length * progress.value);
+      if(tangent ==null) continue;
+      canvas.drawCircle(
+          tangent.position, 5, Paint()..color = Colors.deepOrange);
+    }
+
+    canvas.drawPath(path, paint);
+  }
+
+  @override
+  bool shouldRepaint(PaperPainter oldDelegate) =>
+      oldDelegate.progress != progress;
+}