pub fn of_size(self, width: u32, height: u32) -> Rect {
        assert!(width > 0, "width must be strictly positive");
        assert!(height > 0, "height must be strictly positive");
        Rect {
            left: self.left,
            top: self.top,
            width,
            height,
        }
    }
Construct a rectangle from a position and size. Width and height
are required to be strictly positive.

See the [`Rect`] documentation for examples.
src/rect.rs