Flutter中BottomSheet自定义形状实现求助

我正在开发一个Flutter项目，需要为BottomSheet创建自定义形状。尝试了使用CustomPainter和Clipper的多种实现方式，但始终无法得到想要的精确形状。需要实现的形状如下：

我尝试过多种基于CustomPainter和Clipper的解决方案，但都无法得到理想的形状。以下是我目前的尝试代码示例：

import 'package:flutter/material.dart';

class CustomShapePainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.blue
      ..style = PaintingStyle.fill;

    final path = Path()
      ..moveTo(0, size.height)
      ..quadraticBezierTo(size.width / 2, -size.height, size.width, size.height)
      ..lineTo(size.width, size.height)
      ..lineTo(0, size.height)
      ..close();

    canvas.drawPath(path, paint);
  }

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

内容的提问来源于stack exchange，提问作者Harish Sharma