Would something like
http://www.pentadact.com/2015-01-27-help-me-with-a-trigonometry-problem-for-heat-signature/
Help? He has the solution he found a bit further down in the post.
I'll assume you don't need rotation, because you don't directly mention it in your post.
Actually, assuming that, it just looks like you need to define a world 10 times larger than your screen, and then transform the screen across it. Any objects on screen are at the screen coordinates of
(actualX-screenXTransform,actualY-screenYTransform) Unless I'm grossly misunderstanding something, that should be it.