It is how it’s done in latest version. What version of G’MIC do you use ? Have you tried updating your filters ? This filter works quite fast for me.
That’s wrong. It is actually the expected behavior. Point parameters are supposed to stay constant when the user move the image in the preview window (zooming or panning).
I repeat it probably for a thousand times, but zooming an image preview is most of the time a bad idea, as the preview of a filter is only designed to be accurate at a certain zoom factor. Usually, filters use a 1:1 preview, or a full-size image, and if you deviate from that, you’ll get a warning icon displaying under the preview widget, telling you that the preview is not accurate anymore. I often wonder if we shouldn’t just disable preview zooming for these filters (instead of displaying a warning icon), but I guess that if we do that, some people will complain about the fact they can’t zoom anymore.
There are only a few filters that give accurate previews for any zoom factor, it’s those doing pixel by pixel transformations only (color mixers for instance).