FlutterUnit/lib/app/fun/unit_splash.dart

import 'dart:math';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

/// create by 张风捷特烈 on 2020-03-07
/// contact me by email 1981462002@qq.com
/// 说明:

class FunSplash extends StatefulWidget {
  final double size;

  FunSplash({this.size = 200});

  @override
  _FunSplashState createState() => _FunSplashState();
}

class _FunSplashState extends State<FunSplash>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  double _factor;
  Animation _rotate;

  @override
  void initState() {
    _controller =
        AnimationController(duration: Duration(milliseconds: 5000), vsync: this)
          ..addListener(() => setState(() {
                return _factor = _rotate.value;
              }));
    _rotate = CurvedAnimation(parent: _controller, curve: Curves.bounceOut);
    _controller.forward();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Material(
      child: GestureDetector(
        onTap: () {
          _controller.reset();
          _controller.forward();
        },
        child:  Stack(
          alignment: Alignment.center,
            children: <Widget>[
              FlutterLogo(),
              CustomPaint(
                painter: UnitPainter(factor: _factor),
              ),
            ],
          ),
      ),
    );
  }
}

class UnitPainter extends CustomPainter {
  Paint _paint;
  double width;
  double factor;
  Path _path1 = Path();
  Path _path2 = Path();
  Path _path3 = Path();
  Path _path4 = Path();

  UnitPainter({this.width = 200.0, this.factor}) {
    _paint = Paint()
      ..color = Colors.black
      ..isAntiAlias = true;
  }

  @override
  void paint(Canvas canvas, Size size) {
    canvas.translate(
        size.width / 2 - width * 0.5, size.height / 2 - width * 0.5);

    canvas.save();
    canvas.translate(
        -size.width / 2 * (1 - factor), -size.width / 2 * (1 - factor));
    drawColor1(canvas);
    canvas.restore();

    canvas.save();

    canvas.translate(
        size.width / 2 * (1 - factor), -size.width / 2 * (1 - factor));
    drawColor2(canvas);
    canvas.restore();

    canvas.save();
    canvas.translate(
        size.width / 2 * (1 - factor), size.width / 2 * (1 - factor));
    drawColor3(canvas);
    canvas.restore();

    canvas.save();
    canvas.translate(
        -size.width / 2 * (1 - factor), size.width / 2 * (1 - factor));
    drawColor4(canvas);
    canvas.restore();
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }

  void drawColor1(Canvas canvas) {
    _path1.moveTo(0, 0);
    _path1.lineTo(width * 0.618*factor - 1, 0);
    _path1.lineTo(width * 0.5 - 1, width * 0.5 - 1);
    _path1.lineTo(0, width * (1 - 0.618)*factor - 1);

    canvas.drawPath(_clipAngle(_path1), _paint..color = Colors.red);
  }

  void drawColor2(Canvas canvas) {

    _path2.moveTo(width * 0.618*factor, 0);
    _path2.lineTo(width, 0);
    _path2.lineTo(width, width * 0.618*factor );
    _path2.lineTo(width * 0.5, width * 0.5);

    canvas.drawPath(_clipAngle(_path2), _paint..color = Colors.blue);
  }

  void drawColor3(Canvas canvas) {
    _path3.moveTo(width * 0.5 + 1, width * 0.5 + 1);
    _path3.lineTo(width, width * 0.618*factor + 1);
    _path3.lineTo(width, width);
    _path3.lineTo(width * (1 - 0.618)*factor + 1, width);
    canvas.drawPath(_clipAngle(_path3), _paint..color = Colors.green);
  }

  void drawColor4(Canvas canvas) {
    _path4.moveTo(0, width * (1 - 0.618)*factor);
    _path4.lineTo(width * 0.5, width * 0.5);
    _path4.lineTo(width * (1 - 0.618)*factor, width);
    _path4.lineTo(0, width);
    canvas.drawPath(_clipAngle(_path4), _paint..color = Colors.yellow);
  }

  Path _clipAngle(Path path){
    return Path.combine(
        PathOperation.difference,
        path,
        Path()
          ..addOval(Rect.fromCircle(
              center: Offset(width * 0.5, width * 0.5), radius: 25.0)));
  }
}