I don't see a way to specify the matrix used to perform a desired perspective transformation manually. Of course, I can adjust it by dragging handles, but it would be much easier for me to calculate what I need and then enter the elements of the matrix by hand.
Needless to say, a typical gimp user would not be able to do this, but I am a mathematician who has taught geometry many times during my professional life, so I know what to do. I don't need an explanation of how the matrix is formed and what it does since I can work that out by experimentation. The gimp manual is not helpful. It refers the reader to the section on convolution filters, but that appears to have to do with modifying pixels in place rather than moving the pixels---a rather misleading reference. Perhaps something entirely different happens if you use the full matrix, but the documentation is silent on that matter. Of course, I can try to produce what I want by moving the handles, but for slight adjustments of large images, that is difficult if not impossible. It helps if I increase the magnification enormously, but it is still awkward. It would be a lot simpler to be able to enter the matrix elements directly. -- Leonard Evens <[EMAIL PROTECTED]> Mathematics Department, Northwestern University _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user