Converting to x-bit RGB or palettes above 256?

[Marscaleb]

I'm experimenting with creating pixel art at some various levels of technical quality; creating pixel art constrained to various different systems.

Now for any system or palette that doesn't exceed 256 colors, I can easily convert an image to index mode.
For a 15-bit color palette, I can save an image as a 15-bit .bmp file (or rather, 16-bit with one bit for alpha.)

But what about anything in-between?  Like a 9-bit RGB, or a 12-bit RGB?  Or maybe some other less-popular color combination?  (But 9-bit and 12-bit RGB are the ones I am interested in at this time.)

How can I convert an image to these palettes?  Does someone have a script I can run to make the conversion?

[Ofnuts]

A script wouldn't be that hard to write, how big are the images?

[rich2005]

There is this one

https://github.com/steelwil/gimp-plugin-palette-changer

Which renders a reduced palette

[Marscaleb]

(09-19-2018, 09:17 AM)rich2005 Wrote: There is this one

https://github.com/steelwil/gimp-plugin-palette-changer

Which renders a reduced palette

Thank you!
But I've installed this plug-in, but I don't know how to activate it.  It doesn't ass any features directly into my menu, so far as I can see.
I'm guessing I have to use the script console?  But I've never used that before, and this isn't exactly obvious.  Could you link me to something that explains how to use this plug-in?

[rich2005]

Various ways you can get the plugin, download the zip and unpack
or look at the script, download the raw (no line numbers) this one.

https://github.com/steelwil/gimp-plugin-..._change.py

Either way, gives a file palette_change.py size 3569B which goes in your Gimp 2.x.x user profile.

That is why we ask for your Gimp version number.
Gimp 2.8 C:\Users\"yourname"\.gimp-2.8\plug-ins
or
Gimp 2.10 C:\Users\"your-name"\AppData\Roaming\GIMP\2.10\plug-ins

The plug-in shows up in the menu Filters-> Render-> Palette

Example & comparisons Original + Imported palette with maximum colours then the same after applying the filter

screenshot https://i.imgur.com/GoGhmsP.jpg I don't know if that is what you want. If not back to Ofnuts.

[Marscaleb]

Oh! I see it now. I was looking in the wrong place in the menu after installing it. Thank you!