darkfader

That's what I did. But even then it's difficult because when you change one parameter, all four points will move. So that's why my idea was to remember the last 3 points. It requires only a little bit of math. Hmm... I think the current method can't even get it correct in one time since it only pans after the rotationshit and not before.

I found it extremely difficult to match up two screened layers at all 4 points in the image. It would be really helpful if it could be done like this: (edit: the upper-right point is incorrect but you'll get the point)