如何在Flutter中动态调整CustomPainter的大小？

class MyCustomPaint extends StatefulWidget {
  @override
  _MyCustomPaintState createState() => _MyCustomPaintState();
}

class _MyCustomPaintState extends State<MyCustomPaint> {
  double _painterSize = 100; // 初始大小为100

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onScaleUpdate: (details) {
        setState(() {
          _painterSize = 100 * details.scale; // 根据手势缩放比例动态调整大小
        });
      },
      child: CustomPaint(
        painter: MyCustomPainter(),
        size: Size(_painterSize, _painterSize),
      ),
    );
  }
}

class MyCustomPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    // 在画布上绘制你的图形
    // 可以使用size来动态调整绘制的大小
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return false; // 如果图形不会发生变化，可以返回false以提高性能
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Flutter CustomPainter示例')),
        body: Center(
          child: MyCustomPaint(), // 使用自定义的MyCustomPaint组件
        ),
      ),
    );
  }
}