text background paint

text.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        debugShowCheckedModeBanner: false,
        home: Scaffold(
            body: Center(
                child: Stack(
          children: [
            Text(
                'sadasdasdadsadsadsdsffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffsdadasdadasdd',
                style: TextStyle(
                    color: Colors.transparent,
                    fontWeight: FontWeight.w600,
                    fontSize: 20,
                    background: Paint()
                      ..strokeWidth = 25
                      ..color = Colors.grey
                      ..style = PaintingStyle.stroke
                      ..strokeJoin = StrokeJoin.round)),
            const Text(
                'sadasdasdadsadsadsdsffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffsdadasdadasdd',
                style: TextStyle(
                    fontWeight: FontWeight.w600,
                    fontSize: 20,
                    backgroundColor: Colors.transparent))
          ],
        ))));
  }
}