On Sun, Feb 24, 2019 at 8:30 AM Julien Hardelin <jm.hard@xxxxxxxxxx> wrote: > > Hi devs, > > I can't understand the Inverse Transform option in Little Planet and > Panorama Projection filters, and can't find any explanation about that > on the Internet. > > UI pop help tells "useful for touching up zenith, nadir of other parts > of panorama": how to manage that, I hardly recognize anything in the > inverse transformed image. Both of these operations only work on equirectangular panoramas that are 360x180 degrees. If you have an incomplete panorama, or want to edit out a tripod in nadir - straight down it is difficult directly on the panorama since the bottom is very distorted and distributed all along the bottom of the panorama image. To create a patch for the panorama image with retouched/edited content with the gegl:panorama-projection operation in GIMP you can do the following steps: 1. duplicate layer 2. panorama-projection, adjust it to point straight down with desired zoom (or in some other direction) 3. perform edits to the transformed view of the projection 4. panorama-projection, but this time recall the previous parameter settings from the history list in the operation dialog, and tick the "inverse transform" option 5. optional, merge/down, flatten image This inverse transform in the panorama projection op the transform that happens from lens-normalized input images to merged panorama when creating a panorama with for example hugin. For little-planet it might be a little less useful; but having an inverse transform here serves a similar purpose. /pippin _______________________________________________ gimp-developer-list mailing list List address: gimp-developer-list@xxxxxxxxx List membership: https://mail.gnome.org/mailman/listinfo/gimp-developer-list List archives: https://mail.gnome.org/archives/gimp-developer-list
