image_stack.dart

import 'package:flutter/material.dart';


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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark(),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyHome(),
        ),
      ),
    );
  }
}

class MyHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final stackHeight = MediaQuery.of(context).size.height * 0.5;
    final barHeight = 10.0;
    return Scaffold(
      body: Center(
        child: SizedBox(
          height: stackHeight,
          child: Stack(
            children: [
              Positioned.fill(
                child: Image.network(
                  'https://www.thedesignwork.com/wp-content/uploads/2014/01/animation-gif-2.gif',
                  fit: BoxFit.cover,
                ),
              ),
              Positioned(
                left: 0,
                right: 0,
                height: barHeight,
                bottom: 0,
                child: Container(
                  color: Colors.red,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}