如何在Flutter中在画布上的路径内绘制图案？

import 'package:flutter/material.dart';

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

class MyCustomPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    // 定义路径
    Path path = Path();
    path.addRect(Rect.fromLTRB(50, 50, 200, 200));

    // 绘制路径
    Paint paint = Paint()
      ..color = Colors.blue
      ..style = PaintingStyle.fill;
    canvas.drawPath(path, paint);
  }

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Custom Paint Example'),
        ),
        body: Center(
          child: CustomPaint(
            painter: MyCustomPainter(),
            child: Container(
              width: 300,
              height: 300,
            ),
          ),
        ),
      ),
    );
  }
}