MyClipper

class MyClipper extends CustomClipper<Path> {
  @override
  getClip(Size size) {
    var path = Path();
    path.lineTo(0, size.height - 80);
    path.quadraticBezierTo(
      size.width / 2,
      size.height,
      size.width,
      size.height - 80,
    );
    path.lineTo(size.width, 0);
    path.close();
    return path;
  }

  @override
  bool shouldReclip(covariant CustomClipper oldClipper) {
    return false;
  }
}