This modules shifts an image $in$ into 
$$out(X,Y) = in(X-x,Y-y),$$
where $in$ is assumed to be periodic. If the \verb+-h+ option
is specified instead of \verb+-x+ and \verb+-y+, then the shift 
is equal to half the image size, that is $(x,y)$
for images of size $(2x,2y)$, $(2x+1,2y)$, $(2x,2y+1)$ and $(2x+1,2y+1)$.
If the \verb+-i+ option is selected, then the inverse transform is applied.
\index{translation!of an image}
