Flip Widget Vertically or Horizontally.

flip.dart

class Flip extends StatelessWidget {
  final Widget child;
  final double _scaleX;
  final double _scaleY;

  Flip.vertically({@required this.child})
      : _scaleX = 1.0,
        _scaleY = -1.0;

  Flip.horizontally({@required this.child})
      : _scaleX = -1.0,
        _scaleY = 1.0;

  @override
  Widget build(BuildContext context) {
    return Transform(
      alignment: Alignment.center,
      transform: Matrix4.diagonal3Values(_scaleX, _scaleY, 1.0),
      child: child,
    );
  }
}