Adjust Perspective

I got this app thinking that I would be able to correct the perspective on some architectural photos. All it did was distort them horribly. The slider moves too much too fast and the processing cannot keep up with it. What happens is that you try to compensate for what you just messed up and it makes it even worse. Maybe there should be just a “tilt” function that would change trapezoids to rectangles. Really, that’s all I was trying to do and I never did get it to do that. Worst of all, there is NO undo button. What kind of app doesn’t have an undo??? It reminds me of those kids’ apps that kids use to distort faces.