Evaluating many mildly diverging images is part of image development, but as much as possible should not need to be part of the workflow for operators of software like GIMP. Providing many toggles, options and references is a way to botch complicate the user interface visually as well burden the cognitive load of the operator with choices. The code of the lohalo/nohalo samplers needed revisiting recently (due to hangs/slowdowns which now are resolved) - and as part of that process the choice of a crucial parameter LOHALO_OFFSET0 and NOHALO_OFFSET0 in the respective algorithms deserved revisiting. Test renders of siginificant downscaling producing moire for nearest neighbour and bad values for this parameter can be seen at http://pippin.gimp.org/tmp/samplertest/ the current default is 13; higher values lead to slower processing - for marginally better results. It is probably possible to introduce some level of automation that increases this value as downscaling is made even more aggressive - but values around the current default seem reasonable. Note that for some input images that do not produce moire, results might seem sharper - but there might be lurking surprises in mini-moire patterns and jaggies, for anything but nearest neighbor resampling antialiasing should be expected for scaling of images. The actual reason for this email is that I think it might be overkill to have both lohalo and nohalo available as choices, they are related and powerful transformation ellipsis aware methods, maybe it is sufficient to have one go-to high quality resampler instead of expecting the user to make a choice between lohalo and nohalo on a case by case or built up as general preference, and in which case I believe of these two related methods, from Nicolas Robidoux & collaborators, we'd be best off keeping the nohalo method - possibly with an adaptive _OFFSET0 to speed resampling that is primarily interpolatory. /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
