Donat-Pierre Luigi

This a great application. I would have one request. Would it be possible to calibrate to the image size, with origin at top left max Y at bottom-left and max X at top-right. It is very basic and not as general as the current calibration procedure using 4points.
I am having issues with zoom and ginput to get the coordinate of a point in an image to change the coordinate system to that point later on in pixel and physical units. Thanks.