castome shape

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: Scaffold(
          body: Center(
            child: Material(
              elevation: 10,
              child: Container(
                width: 230,
                height: 230,
                decoration: const ShapeDecoration(
                  shape: MessageBorder(),
                  // color: Colors.teal,
                  gradient: RadialGradient(colors: [
                    Colors.red,
                    Colors.green,
                    Colors.blue,
                  ]),
                  shadows: [
                    BoxShadow(
                        color: Colors.black,
                        offset: Offset(0, 0),
                        blurRadius: 0,
                        spreadRadius: 30),
                    BoxShadow(
                      color: Colors.blue,
                      offset: Offset(0, 0),
                      blurRadius: 0,
                    ),
                  ],
                ),
              ),
            ),
          ),
        ));
  }
}

class MessageBorder extends ShapeBorder {
  final bool usePadding;

  const MessageBorder({this.usePadding = true});

  @override
  EdgeInsetsGeometry get dimensions => const EdgeInsets.only(bottom: 0);

  @override
  Path getInnerPath(Rect rect, {TextDirection? textDirection}) =>
      getOuterPath(rect, textDirection: textDirection);

  @override
  Path getOuterPath(Rect rect, {TextDirection? textDirection}) {
    rect = Rect.fromPoints(rect.topLeft - const Offset(-10, -10),
        rect.bottomRight - const Offset(0, 0));

    return Path()
      ..moveTo(143.58 + rect.left, 0 + rect.top)
      ..cubicTo(148.42 + rect.left, -7.37 + rect.top, 159.88 + rect.left,
          -2.62 + rect.top, 158.1 + rect.left, 6.01 + rect.top)
      ..lineTo(147.28 + rect.left, 58.34 + rect.top)
      ..cubicTo(146.12 + rect.left, 63.97 + rect.top, 151.1 + rect.left,
          68.96 + rect.top, 156.74 + rect.left, 67.79 + rect.top)
      ..lineTo(209.06 + rect.left, 56.98 + rect.top)
      ..cubicTo(217.7 + rect.left, 55.2 + rect.top, 222.45 + rect.left,
          66.65 + rect.top, 215.08 + rect.left, 71.5 + rect.top)
      ..lineTo(170.43 + rect.left, 100.85 + rect.top)
      ..cubicTo(165.62 + rect.left, 104.01 + rect.top, 165.62 + rect.left,
          111.06 + rect.top, 170.43 + rect.left, 114.22 + rect.top)
      ..lineTo(215.08 + rect.left, 143.58 + rect.top)
      ..cubicTo(222.45 + rect.left, 148.42 + rect.top, 217.7 + rect.left,
          159.88 + rect.top, 209.06 + rect.left, 158.1 + rect.top)
      ..lineTo(156.74 + rect.left, 147.28 + rect.top)
      ..cubicTo(151.1 + rect.left, 146.12 + rect.top, 146.12 + rect.left,
          151.1 + rect.top, 147.28 + rect.left, 156.74 + rect.top)
      ..lineTo(158.1 + rect.left, 209.06 + rect.top)
      ..cubicTo(159.88 + rect.left, 217.7 + rect.top, 148.42 + rect.left,
          222.45 + rect.top, 143.58 + rect.left, 215.08 + rect.top)
      ..lineTo(114.22 + rect.left, 170.43 + rect.top)
      ..cubicTo(111.06 + rect.left, 165.62 + rect.top, 104.01 + rect.left,
          165.62 + rect.top, 100.85 + rect.left, 170.43 + rect.top)
      ..lineTo(71.5 + rect.left, 215.08 + rect.top)
      ..cubicTo(66.65 + rect.left, 222.45 + rect.top, 55.2 + rect.left,
          217.7 + rect.top, 56.98 + rect.left, 209.06 + rect.top)
      ..lineTo(67.79 + rect.left, 156.74 + rect.top)
      ..cubicTo(68.96 + rect.left, 151.1 + rect.top, 63.97 + rect.left,
          146.12 + rect.top, 58.34 + rect.left, 147.28 + rect.top)
      ..lineTo(6.01 + rect.left, 158.1 + rect.top)
      ..cubicTo(-2.62 + rect.left, 159.88 + rect.top, -7.37 + rect.left,
          148.42 + rect.top, 0 + rect.left, 143.58 + rect.top)
      ..lineTo(44.65 + rect.left, 114.22 + rect.top)
      ..cubicTo(49.45 + rect.left, 111.06 + rect.top, 49.45 + rect.left,
          104.01 + rect.top, 44.65 + rect.left, 100.85 + rect.top)
      ..lineTo(0 + rect.left, 71.5 + rect.top)
      ..cubicTo(-7.37 + rect.left, 66.65 + rect.top, -2.62 + rect.left,
          55.2 + rect.top, 6.01 + rect.left, 56.98 + rect.top)
      ..lineTo(58.34 + rect.left, 67.79 + rect.top)
      ..cubicTo(63.97 + rect.left, 68.96 + rect.top, 68.96 + rect.left,
          63.97 + rect.top, 67.79 + rect.left, 58.34 + rect.top)
      ..lineTo(56.98 + rect.left, 6.01 + rect.top)
      ..cubicTo(55.2 + rect.left, -2.62 + rect.top, 66.65 + rect.left,
          -7.37 + rect.top, 71.5 + rect.left, 0 + rect.top)
      ..lineTo(100.85 + rect.left, 44.65 + rect.top)
      ..cubicTo(104.01 + rect.left, 49.45 + rect.top, 111.06 + rect.left,
          49.45 + rect.top, 114.22 + rect.left, 44.65 + rect.top)
      ..lineTo(143.58 + rect.left, 0 + rect.top)
      ..close();
  }

  @override
  void paint(Canvas canvas, Rect rect, {TextDirection? textDirection}) {}

  @override
  ShapeBorder scale(double t) => this;
}