books

assets/draw/p03/p03.dart

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+export 'p03_page.dart';

assets/draw/p03/p03_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;
+import 's07.dart' as s7;
+import 's08.dart' as s8;
+import 's09.dart' as s9;
+import 's10.dart' as s10;
+import 's11.dart' as s11;
+import 's12.dart' as s12;
+import 's13.dart' as s13;
+
+class P03Page extends StatelessWidget {
+  const P03Page({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const DemoShower(
+      srcCodeDir: 'draw/p03',
+      demos:  [
+        s1.Paper(),
+        s2.Paper(),
+        s3.Paper(),
+        s4.Paper(),
+        s5.Paper(),
+        s6.Paper(),
+        s7.Paper(),
+        s8.Paper(),
+        s9.Paper(),
+        s10.Paper(),
+        s11.Paper(),
+        s12.Paper(),
+        s13.Paper(),
+      ],
+    );
+  }
+}

assets/draw/p03/s01.dart

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+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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 {
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    var paint = Paint()
+      ..style = PaintingStyle.fill
+      ..color = Colors.blue;
+    // 画布起点移到屏幕中心
+    canvas.translate(size.width / 2, size.height / 2);
+    canvas.drawCircle(Offset(0, 0), 50, paint);
+    canvas.drawLine(
+        Offset(20, 20),
+        Offset(50, 50),
+        paint
+          ..color = Colors.red
+          ..strokeWidth = 5
+          ..strokeCap = StrokeCap.round
+          ..style = PaintingStyle.stroke);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s02.dart

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

assets/draw/p03/s03.dart

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+import 'dart:math';
+import 'package:flutter/material.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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 {
+  late Paint _gridPint;
+  final double step = 20;
+  final double strokeWidth = .5;
+
+  PaperPainter() {
+    _gridPint = Paint()
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = strokeWidth
+      ..color = Colors.grey;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    canvas.translate(size.width / 2, size.height / 2);
+    _drawGrid(canvas, size);
+
+    var paint = Paint()
+      ..style = PaintingStyle.fill
+      ..color = Colors.blue;
+
+    _drawPart(canvas, paint);
+    _drawDot(canvas, paint);
+  }
+
+  void _drawPart(Canvas canvas, Paint paint) {
+    canvas.drawCircle(Offset(0, 0), 50, paint);
+    canvas.drawLine(
+        Offset(20, 20),
+        Offset(50, 50),
+        paint
+          ..color = Colors.red
+          ..strokeWidth = 5
+          ..strokeCap = StrokeCap.round
+          ..style = PaintingStyle.stroke);
+  }
+
+  void _drawDot(Canvas canvas, Paint paint) {
+    final int count = 12;
+    paint
+      ..color = Colors.orangeAccent
+      ..style = PaintingStyle.stroke;
+    canvas.save();
+    for (int i = 0; i < count; i++) {
+      var step = 2 * pi / count;
+      canvas.drawLine(Offset(80, 0), Offset(100, 0), paint);
+      canvas.rotate(step);
+    }
+    canvas.restore();
+  }
+
+  void _drawGrid(Canvas canvas, Size size) {
+    _drawBottomRight(canvas, size);
+
+    canvas.save();
+    canvas.scale(1, -1); //沿x轴镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+
+    canvas.save();
+    canvas.scale(-1, 1); //沿y轴镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+
+    canvas.save();
+    canvas.scale(-1, -1); //沿原点镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+  }
+
+  void _drawBottomRight(Canvas canvas, Size size) {
+    canvas.save();
+    for (int i = 0; i < size.height / 2 / step; i++) {
+      canvas.drawLine(Offset(0, 0), Offset(size.width / 2, 0), _gridPint);
+      canvas.translate(0, step);
+    }
+    canvas.restore();
+
+    canvas.save();
+    for (int i = 0; i < size.width / 2 / step; i++) {
+      canvas.drawLine(Offset(0, 0), Offset(0, size.height / 2), _gridPint);
+      canvas.translate(step , 0);
+    }
+    canvas.restore();
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s04.dart

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+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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 {
+  late Paint _paint;
+
+  late Paint _gridPint;
+  final double step = 20;
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+    _gridPint = Paint()
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = strokeWidth
+      ..color = Colors.grey;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    canvas.translate(size.width / 2, size.height / 2);
+    _drawGrid(canvas, size);
+    _drawAxis(canvas,size);
+
+    _drawPointsWithPoints(canvas);
+    // _drawPointsWithLines(canvas);
+    _drawPointLineWithPolygon(canvas);
+    _drawRawPoints(canvas);
+  }
+
+  final List<Offset> points = [
+    Offset(-120, -20),
+    Offset(-80, -80),
+    Offset(-40, -40),
+    Offset(0, -100),
+    Offset(40, -140),
+    Offset(80, -160),
+    Offset(120, -100),
+  ];
+
+  void _drawPointsWithPoints(Canvas canvas) {
+    _paint
+      ..color = Colors.red
+      ..style = PaintingStyle.stroke..strokeWidth=10
+      ..strokeCap = StrokeCap.round;
+    canvas.drawPoints(PointMode.points, points, _paint);
+  }
+
+  void _drawPointsWithLines(Canvas canvas) {
+    _paint
+      ..color = Colors.red
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 1
+      ..strokeCap = StrokeCap.round;
+    canvas.drawPoints(PointMode.lines, points, _paint);
+  }
+
+  void _drawPointLineWithPolygon(Canvas canvas) {
+    _paint
+      ..color = Colors.red
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 1
+      ..strokeCap = StrokeCap.round;
+    canvas.drawPoints(PointMode.polygon, points, _paint);
+  }
+
+  void _drawRawPoints(Canvas canvas) {
+    Float32List pos = Float32List.fromList([
+      -120, -20,-80, -80,-40,
+      -40,0, -100,40, -140,
+      80, -160,120, -100]);
+    _paint
+      ..color = Colors.red
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 10
+      ..strokeCap = StrokeCap.round;
+    canvas.drawRawPoints(PointMode.points, pos, _paint);
+  }
+
+  void _drawAxis(Canvas canvas, Size size) {
+    _paint..color=Colors.blue..strokeWidth=1.5;
+    canvas.drawLine(Offset(-size.width/2, 0) , Offset(size.width/2, 0),_paint);
+    canvas.drawLine(Offset( 0,-size.height/2) , Offset( 0,size.height/2),_paint);
+    canvas.drawLine(Offset( 0,size.height/2) , Offset( 0-7.0,size.height/2-10),_paint);
+    canvas.drawLine(Offset( 0,size.height/2) , Offset( 0+7.0,size.height/2-10),_paint);
+    canvas.drawLine(Offset(size.width/2, 0) , Offset(size.width/2-10, 7),_paint);
+    canvas.drawLine(Offset(size.width/2, 0) , Offset(size.width/2-10, -7),_paint);
+  }
+
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+
+  void _drawGrid(Canvas canvas, Size size) {
+    _drawBottomRight(canvas, size);
+    canvas.save();
+    canvas.scale(1, -1); //沿x轴镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+
+    canvas.save();
+    canvas.scale(-1, 1); //沿y轴镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+
+    canvas.save();
+    canvas.scale(-1, -1); //沿原点镜像
+    _drawBottomRight(canvas, size);
+    canvas.restore();
+  }
+
+  void _drawBottomRight(Canvas canvas, Size size) {
+    canvas.save();
+    for (int i = 0; i < size.height / 2 / step; i++) {
+      canvas.drawLine(Offset(0, 0), Offset(size.width / 2, 0), _gridPint);
+      canvas.translate(0, step);
+    }
+    canvas.restore();
+
+    canvas.save();
+    for (int i = 0; i < size.width / 2 / step; i++) {
+      canvas.drawLine(Offset(0, 0), Offset(0, size.height / 2), _gridPint);
+      canvas.translate(step , 0);
+    }
+    canvas.restore();
+  }
+
+
+}

assets/draw/p03/s05.dart

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+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  late Paint _paint;
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+
+    canvas.translate(size.width / 2, size.height / 2);
+
+    _drawDRRect(canvas);
+
+    canvas.translate(-240, 0);
+    _drawRect(canvas);
+
+    canvas.translate(480, 0);
+    _drawRRect(canvas);
+  }
+
+  void _drawRect(Canvas canvas) {
+    _paint
+      ..color = Colors.blue
+      ..strokeWidth = 1.5;
+    //【1】.矩形中心构造
+    Rect rectFromCenter =
+    Rect.fromCenter(center: Offset(0, 0), width: 160, height: 160);
+    canvas.drawRect(rectFromCenter, _paint);
+    //【2】.矩形左上右下构造
+    Rect rectFromLTRB = Rect.fromLTRB(-120, -120, -80, -80);
+    canvas.drawRect(rectFromLTRB, _paint..color = Colors.red);
+    //【3】. 矩形左上宽高构造
+    Rect rectFromLTWH = Rect.fromLTWH(80, -120, 40, 40);
+    canvas.drawRect(rectFromLTWH, _paint..color = Colors.orange);
+    //【4】. 矩形内切圆构造
+    Rect rectFromCircle = Rect.fromCircle(center: Offset(100, 100), radius: 20);
+    canvas.drawRect(rectFromCircle, _paint..color = Colors.green);
+    //【5】. 矩形两点构造
+    Rect rectFromPoints = Rect.fromPoints(Offset(-120, 80), Offset(-80, 120));
+    canvas.drawRect(rectFromPoints, _paint..color = Colors.purple);
+  }
+
+  void _drawRRect(Canvas canvas) {
+    _paint
+      ..color = Colors.blue
+      ..strokeWidth = 1.5;
+    //【1】.圆角矩形fromRectXY构造
+    Rect rectFromCenter =
+    Rect.fromCenter(center: Offset(0, 0), width: 160, height: 160);
+    canvas.drawRRect(RRect.fromRectXY(rectFromCenter, 40, 20), _paint);
+
+    //【2】.圆角矩形fromLTRBXY构造
+    canvas.drawRRect(RRect.fromLTRBXY(-120, -120, -80, -80, 10, 10),
+        _paint..color = Colors.red);
+
+    //【3】. 圆角矩形fromLTRBR构造
+    canvas.drawRRect(RRect.fromLTRBR(80, -120, 120, -80, Radius.circular(10)),
+        _paint..color = Colors.orange);
+
+    //【4】. 圆角矩形fromLTRBAndCorners构造
+    canvas.drawRRect(
+        RRect.fromLTRBAndCorners(80, 80, 120, 120,
+            bottomRight: Radius.elliptical(10, 10)),
+        _paint..color = Colors.green);
+
+    //【5】. 矩形两点构造
+    Rect rectFromPoints = Rect.fromPoints(Offset(-120, 80), Offset(-80, 120));
+    canvas.drawRRect(
+        RRect.fromRectAndCorners(rectFromPoints,
+            bottomLeft: Radius.elliptical(10, 10)),
+        _paint..color = Colors.purple);
+  }
+
+  void _drawDRRect(Canvas canvas) {
+    _paint
+      ..color = Colors.blue
+      ..strokeWidth = 1.5;
+    Rect outRect =
+    Rect.fromCenter(center: Offset(0, 0), width: 160, height: 160);
+    Rect inRect =
+    Rect.fromCenter(center: Offset(0, 0), width: 100, height: 100);
+
+    canvas.drawDRRect(RRect.fromRectXY(outRect, 20, 20),
+        RRect.fromRectXY(inRect, 20, 20), _paint);
+
+    Rect outRect2 =
+    Rect.fromCenter(center: Offset(0, 0), width: 60, height: 60);
+    Rect inRect2 = Rect.fromCenter(center: Offset(0, 0), width: 40, height: 40);
+    canvas.drawDRRect(RRect.fromRectXY(outRect2, 15, 15),
+        RRect.fromRectXY(inRect2, 10, 10), _paint..color = Colors.green);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s06.dart

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+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  late Paint _paint;
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+    _draw(canvas);
+  }
+
+  void _draw(Canvas canvas) {
+    canvas.save();
+    canvas.translate(-200, 0);
+    canvas.drawCircle(Offset(0, 0), 60, _paint);
+    canvas.restore();
+
+    var rect = Rect.fromCenter(center: Offset(0, 0), height: 100, width: 120);
+    canvas.drawOval(rect, _paint);
+
+    canvas.save();
+    canvas.translate(200, 0);
+    //drawArc(矩形区域,起始弧度,扫描弧度,是否连中心,画笔)
+    canvas.drawArc(rect, 0, pi / 2 * 3, true, _paint);
+    canvas.restore();
+  }
+
+  void _drawArcDetail(Canvas canvas) {
+    var rect = Rect.fromCenter(center: Offset(0, 0), height: 100, width: 100);
+    _paint
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = 2;
+    canvas.save();
+    canvas.translate(-200, 0);
+    canvas.drawArc(rect, 0, pi / 2 * 3, false, _paint);
+    canvas.restore();
+    canvas.drawArc(rect, 0, pi / 2 * 3, true, _paint);
+    canvas.save();
+    canvas.translate(200, 0);
+    var a = pi / 8;
+    canvas.drawArc(rect, a, 2 * pi - a.abs() * 2, true, _paint..color=Colors.yellowAccent..style=PaintingStyle.fill);
+    canvas.translate(40, 0);
+    canvas.drawCircle(Offset(0, 0), 6, _paint);
+    canvas.translate(25, 0);
+    canvas.drawCircle(Offset(0, 0), 6, _paint);
+    canvas.restore();
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s07.dart

@@ -0,0 +1,45 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+    canvas.drawColor(Colors.blue, BlendMode.lighten);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s08.dart

@@ -0,0 +1,74 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  late Paint _paint;
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+
+    var colors = [
+      Color(0xFFF60C0C),
+      Color(0xFFF3B913),
+      Color(0xFFE7F716),
+      Color(0xFF3DF30B),
+      Color(0xFF0DF6EF),
+      Color(0xFF0829FB),
+      Color(0xFFB709F4),
+    ];
+
+    var pos = [1.0 / 7, 2.0 / 7, 3.0 / 7, 4.0 / 7, 5.0 / 7, 6.0 / 7, 1.0];
+
+    _paint.shader = ui.Gradient.linear(
+        Offset(0, 0), Offset(size.width, 0),
+        colors, pos, TileMode.clamp);
+
+    _paint.blendMode=BlendMode.lighten;
+
+    canvas.drawPaint(_paint);
+  }
+
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s09.dart

@@ -0,0 +1,73 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    // coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Paint paint = Paint()
+      ..style = PaintingStyle.fill
+      ..color = Colors.white
+      ..isAntiAlias = true;
+    double relativeX = 100;
+    double angle = 0;
+    double width = 10;
+    double height = 10;
+    double center =  relativeX + width / 2;
+    if(angle == 0) {
+      center = relativeX + width/4;
+    } else if (angle == 2) {
+      center = relativeX + width/4*3;
+    }
+
+    Path trianglePath = Path()
+      ..addPolygon([Offset(relativeX, height), Offset(relativeX + width, height), Offset(center, 0),], false)..close();
+
+    Path rectanglePath = Path()
+      ..addRRect(RRect.fromLTRBR(0, 10, 160, 100, Radius.circular(8)))..close();
+
+
+    canvas.drawShadow(Path.combine(PathOperation.xor, trianglePath, rectanglePath), Colors.black, 3, false);
+    canvas.drawPath(Path.combine(PathOperation.xor, trianglePath, rectanglePath), paint..color = Colors.white);
+    paint.maskFilter = MaskFilter.blur(BlurStyle.inner, 20);
+    canvas.drawPath(Path.combine(PathOperation.xor, trianglePath, rectanglePath), paint..color=Color(0xffBEC4C0));
+
+  }
+
+
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s10.dart

@@ -0,0 +1,68 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  late Paint _paint;
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+    path.lineTo(60, 60);
+    path.lineTo(-60, 60);
+    path.lineTo(60, -60);
+    path.lineTo(-60, -60);
+    path.close();
+
+    canvas.drawPath(path, _paint);
+    canvas.translate(140, 0);
+    canvas.drawPath(
+        path,
+        _paint
+          ..style = PaintingStyle.stroke
+          ..strokeWidth = 2);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s11.dart

@@ -0,0 +1,79 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  late Paint _paint;
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  PaperPainter() {
+    _paint = Paint()
+      ..style = PaintingStyle.fill
+      ..strokeWidth = strokeWidth
+      ..color = color;
+  }
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    // canvas.save();
+    var rect = Rect.fromCenter(center: Offset.zero,width: 360,height: 240);
+    canvas.clipRect(rect,doAntiAlias: true,clipOp: ui.ClipOp.intersect);
+
+    var colors = [
+      Color(0xFFF60C0C),
+      Color(0xFFF3B913),
+      Color(0xFFE7F716),
+      Color(0xFF3DF30B),
+      Color(0xFF0DF6EF),
+      Color(0xFF0829FB),
+      Color(0xFFB709F4),
+    ];
+
+    var pos = [1.0 / 7, 2.0 / 7, 3.0 / 7, 4.0 / 7, 5.0 / 7, 6.0 / 7, 1.0];
+
+    _paint.shader = ui.Gradient.linear(
+        rect.centerLeft, rect.centerRight,
+        colors, pos, TileMode.clamp);
+
+    _paint.blendMode=BlendMode.lighten;
+
+    canvas.drawPaint(_paint);
+    // canvas.restore();
+    // canvas.drawColor(Colors.blue, BlendMode.lighten);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s12.dart

@@ -0,0 +1,49 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    // canvas.save();
+    var rect = Rect.fromCenter(center: Offset.zero,width: 200,height: 100);
+    canvas.clipRRect(RRect.fromRectAndRadius(rect, Radius.circular(30)));
+    canvas.drawColor(Colors.red, BlendMode.darken);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}

assets/draw/p03/s13.dart

@@ -0,0 +1,52 @@
+import 'dart:math';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+import '../components/coordinate.dart';
+
+/// create by 张风捷特烈 on 2020-03-19
+/// contact me by email 1981462002@qq.com
+/// 说明: 纸
+
+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();
+
+  final double strokeWidth = 0.5;
+  final Color color = Colors.blue;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    coordinate.paint(canvas, size);
+    canvas.translate(size.width / 2, size.height / 2);
+
+    Path path = Path();
+    path.lineTo(80, 80);
+    path.lineTo(-80, 80);
+    path.close();
+
+    canvas.clipPath(path);
+    canvas.drawColor(Colors.red, BlendMode.darken);
+  }
+
+  @override
+  bool shouldRepaint(CustomPainter oldDelegate) => false;
+}