(10-26-2020, 07:02 AM)Ottia Tuota Wrote: So, for example if you choose some four points A,B,C,D from the circumference of your clock face, and corresponding four points P,Q,R,S from a circle, the created transformation should be the one needed.
The problem is that its difficult to figure out the 4 points that should correspond to 4 known points on the final correct circle. It is however possible to indicate 4 points on the distorted circle, but nothing more. So the question is, given 4 points, is there a way to compute the Projective transform (is this transform unique? additional constraints are possible to make it unique, such as keeping the distance between two points identical, or keepin the orientation between two given points, or both)) than puts them on a circle? If I have this transform, I can figure out a way to use it with gimp_item_transform_perspective().