[SOLVED]Help with Image Cropping

Hello! I need to create something like a selector for an image so I can choose which part of the image i want to keep (whole image, bits and pieces etc.) AKA crop the image. I know I can use QPixmap::copy for the actual cropping but I need to get the point from which to crop, width and height (via a selector). I have no idea what to use to do this :D Any help would be much appreciated.