-- | Invertible conversion.

c2r :: RectC -> Rectangle
c2r (RectC (x1, y1, x2, y2)) = Rectangle (fi x1) (fi y1) (fi $ x2 - x1 + 1) (fi $ y2 - y1 + 1)
c2r :: RectC -> Rectangle
c2r (RectC (x1, y1, x2, y2)) = Rectangle (fi x1) (fi y1) (fi $ x2 - x1 + 1) (fi $ y2 - y1 + 1)
c2r (RectC (x1, y1, x2, y2)) = Rectangle (fi x1) (fi y1) (fi $ x2 - x1 + 1) (fi $ y2 - y1 + 1)