content: import 'package:flutter/material.dart';
  import 'package:url_launcher/url_launcher.dart';
  
  class Day70ShaderMask extends StatelessWidget {
    const Day70ShaderMask({Key key}) : super(key: key);
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        backgroundColor: Colors.black,
        body: Center(
          /**
           * ? What is ShaderMask....
           * ! ShaderMask is the cool effect for the any white screen....
           * ! Where every white screen filled by shader....
           */
          child: ShaderMask(
            // ! here comes the ShaderMask....
            shaderCallback: (bounds) => RadialGradient(
              // ! With RadialGradient as the [shaderCallback]....
              colors: [
                Colors.yellow,
                Colors.orange,
                Colors.deepOrange,
                Colors.red
              ],
              radius: 5.0,
            ).createShader(bounds), // ! createShader with the [bounds]....
            child: Stack(
              // ! here we apply the ShaderMask for the Stack....
              alignment: Alignment.center,
              children: <Widget>[
                Container(
                  width: MediaQuery.of(context).size.width * 0.7,
                  height: MediaQuery.of(context).size.height * 0.7,
                  color: Colors
                      .white, // ! This White [Container] filled by the ShaderMask Gradient....
                ),
                Container(
                  width: MediaQuery.of(context).size.width * 0.5,
                  height: MediaQuery.of(context).size.height * 0.5,
                  color: Colors.black,
                  child: Center(
                    child: Text(
                      "This is Shaded Text",
                      style: TextStyle(
                        fontSize: 20,
                        color: Colors
                            .white, // ! This White [Text] filled by the ShaderMask Gradient....
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
        appBar: AppBar(
          title: Text('ShaderMask'),
          actions: <Widget>[
            IconButton(
              icon: Icon(Icons.help),
              onPressed: () async {
                const url =
                    'https://github.com/sanjaysanju618/100-Days-Of-Flutter-Widgets/' +
                        'blob/master/hundred_days_of_flutter_widget/' +
                        'lib/day070_shader_mask.dart';
                if (await canLaunch(url)) {
                  await launch(url);
                } else {
                  throw 'Could not launch $url';
                }
              },
            )
          ],
        ),
      );
    }
  }
  