Zoom with drag and drop - Flutter

container.dart

...

class _MyHomePageState extends State<MyHomePage> {
  File _image;

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Stack(
        children: <Widget>[
          new Container(
            child: _image == null ? null : new Image.file(_image),
          ),
          new Positioned(
            bottom: 15.0,
            left: 15.0,
            child: new FloatingActionButton(
              onPressed: _initGallery,
              child: new Icon(Icons.collections),
            ),
          ),
        ],
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _initCamera,
        child: new Icon(Icons.camera_alt),
      ),
    );
  }