import 'dart:math';
import 'dart:ui';

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  double rotate = 45.0 * pi / 180.0;

  Widget makeRow(double cornerSize, double blurSize) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
      children: <Widget>[
        CustomPaint(
          painter: _RRectPainter(
            cornerSize: cornerSize,
            blurSize: blurSize,
            scale: 0.5,
            rotate: rotate,
          ),
          size: const Size(150, 150),
        ),
        CustomPaint(
          painter: _RRectPathPainter(
            cornerSize: cornerSize,
            blurSize: blurSize,
            scale: 0.5,
            rotate: rotate,
          ),
          size: const Size(150, 150),
        ),
        CustomPaint(
          painter: _RRectPainter(
            cornerSize: cornerSize,
            blurSize: blurSize,
            scale: 1.0,
            rotate: rotate,
          ),
          size: const Size(150, 150),
        ),
        CustomPaint(
          painter: _RRectPathPainter(
            cornerSize: cornerSize,
            blurSize: blurSize,
            scale: 1.0,
            rotate: rotate,
          ),
          size: const Size(150, 150),
        ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: <Widget>[
            makeRow(10, 10),
            makeRow(10, 30),
            makeRow(10, 50),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                const Text('rotation'),
                Slider(
                  value: rotate,
                  min: 0.0,
                  max: pi * 2.0,
                  onChanged: (value) {
                    setState(() {
                      rotate = value;
                    });
                  },
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _RRectPainter extends CustomPainter {
  _RRectPainter({
    required this.cornerSize,
    required this.blurSize,
    required this.scale,
    required this.rotate,
  });

  final double cornerSize;
  final double blurSize;
  final double scale;
  final double rotate;

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

    canvas.scale(scale, scale);
    double w = size.width / scale;
    double h = size.height / scale;
    double c = cornerSize / scale;

    Rect rect = Rect.fromLTRB(0, 0, w, h);
    RRect rrect = RRect.fromRectXY(rect, c, c);

    Paint paint = Paint()
      ..imageFilter = ImageFilter.blur(sigmaX: blurSize, sigmaY: 0.0, tileMode: TileMode.decal)
      // ..maskFilter = MaskFilter.blur(BlurStyle.normal, blurSize)
      ..color = Colors.blue;
    canvas.drawRRect(rrect, paint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => true;
}

class _RRectPathPainter extends CustomPainter {
  _RRectPathPainter({
    required this.cornerSize,
    required this.blurSize,
    required this.scale,
    required this.rotate,
  });

  final double cornerSize;
  final double blurSize;
  final double scale;
  final double rotate;

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

    canvas.scale(scale, scale);
    double w = size.width / scale;
    double h = size.height / scale;
    double c = cornerSize / scale;

    Path path = Path();
    path.addRect(Rect.fromLTRB(c, 0, w - c, h));
    path.addRect(Rect.fromLTRB(0, c, w, h - c));
    path.addOval(Rect.fromLTRB(0, 0, c * 2, c * 2));
    path.addOval(Rect.fromLTRB(w - c * 2, 0, w, c * 2));
    path.addOval(Rect.fromLTRB(0, h - c * 2, c * 2, h));
    path.addOval(Rect.fromLTRB(w - c * 2, h - c * 2, w, h));

    Paint paint = Paint()
      ..imageFilter = ImageFilter.blur(sigmaX: blurSize, sigmaY: 0.0, tileMode: TileMode.decal)
      // ..maskFilter = MaskFilter.blur(BlurStyle.normal, blurSize)
      ..color = Colors.blue;
    canvas.drawPath(path, paint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => true;
}