Custom HSV Transform Palette
Operating System: Any
Description of the feature
Using custom hue-saturation palette to transform a bitmap.
Use cases
When using builtin Gimp HSV filters (hue-chroma, hue-saturation), results look a bit washed out or otherwise don't match expectations. The maps behind these filters are also obscure. By exposing these maps for editing and allowing to specify custom hue map would solve it. Here is an example how high brightness looks in GIMP, and how it should look to actually appear bright:
And here is an example of a custom HSV palette:
Now user can directly edit this palette, like any other bitmap, instantly getting changes on screen, without damaging the original image.
You can implement the transfer from rgb into such palette by using kdtree/octree lookup, just like you do with usual conversion to indexed color. The light component could also win from some optional HDR treatment during transfer back to rgb.