box method Null safety

Widget box(
  1. Rect pos,
  2. Widget child
)

x, y, w and h are in cm

Implementation

Widget box(final Rect pos, final Widget child) {
  final double dx = (pos.width >= width) ? 0 : pos.left / (width - pos.width);
  final double dy =
      (pos.height >= height) ? 0 : pos.top / (height - pos.height);
  return Align(
      alignment: FractionalOffset(dx, dy),
      child: FractionallySizedBox(
          widthFactor: pos.width / width,
          heightFactor: pos.height / height,
          child: child));
}