books

assets/draw/p11/s01.dart

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+
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+import '../components/coordinate_pro.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 Center(
+      child: CurveBox(curve: const Cubic(1, -0.06, 0.1, 1.2),),
+    );
+  }
+}
+
+
+class CurveBox extends StatefulWidget {
+  final Color color;
+  final Curve curve;
+
+  CurveBox({Key? key, this.color = Colors.lightBlue, this.curve = Curves.linear})
+      : super(key: key);
+
+  @override
+  _CurveBoxState createState() => _CurveBoxState();
+}
+
+class _CurveBoxState extends State<CurveBox>
+    with SingleTickerProviderStateMixin {
+  late AnimationController _controller;
+  late Animation<double> _angleAnimation;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = AnimationController(
+      duration: const Duration(seconds: 3),
+      vsync: this,
+    );
+    _angleAnimation = CurveTween(curve: widget.curve).animate(_controller);
+    _controller.repeat();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return CustomPaint(
+      size: Size(100, 100),
+      painter: CurveBoxPainter(_controller, _angleAnimation), // 背景
+    );
+  }
+}
+
+class CurveBoxPainter extends CustomPainter {
+  final Animation<double> repaint; //
+  Animation<double> angleAnimation;
+
+  Paint _paint = Paint();
+
+  CurveBoxPainter(this.repaint, this.angleAnimation) : super(repaint: repaint) {}
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    canvas.clipRect(Offset.zero & size);
+    canvas.translate(size.width / 2, size.height / 2);
+    _drawRing(canvas, size);
+    _drawRedCircle(canvas, size);
+    _drawGreenCircle(canvas, size);
+  }
+
+  //绘制环
+  void _drawRing(Canvas canvas, Size size) {
+    final double strokeWidth = 5;
+    _paint
+      ..color = Colors.blue
+      ..style = PaintingStyle.stroke
+      ..strokeWidth = strokeWidth;
+    canvas.drawCircle(Offset.zero, size.width / 2 - strokeWidth, _paint);
+  }
+
+  // 绘制红球
+  void _drawRedCircle(Canvas canvas, Size size) {
+    canvas.save();
+    canvas.rotate(angleAnimation.value * 2 * pi);
+    _paint
+      ..color = Colors.red
+      ..style = PaintingStyle.fill;
+    canvas.drawCircle(
+        Offset.zero.translate(0, -(size.width / 2 - 5)), 5, _paint);
+    canvas.restore();
+  }
+
+  // 绘制绿球
+  void _drawGreenCircle(Canvas canvas, Size size) {
+    canvas.save();
+    canvas.translate(0,angleAnimation.value * (size.height-10));
+    _paint
+      ..color = Colors.green
+      ..style = PaintingStyle.fill;
+    canvas.drawCircle(
+        Offset.zero.translate(0, -(size.width / 2 - 5)), 5, _paint);
+    canvas.restore();
+  }
+
+  @override
+  bool shouldRepaint(covariant CurveBoxPainter oldDelegate) =>
+      oldDelegate.repaint != repaint;
+}