compress hue range of an image

[bugblatterbeast]

Hi,

I want to reduce the hue range of an image by dividing all hue-values by a variable value without touching the saturation- and lightness-values (any more sophisticated projection of the hue-range would also be very interesting).

I am looking for an automatic process that could for example turn the 1st attached image (temp_full_hue.png) into the 2nd attached image (temp_half_hue.png).

Ofc it wouldn't matter where the resulting hue starts, since I'd be able to shift it to wherever I want.

Kind regards

edit: updated images

[Ofnuts]

Color>Map>Rotate colors will do it:

   

(above, mapped 0->360 to 90->270).

[rich2005]

Linux, Gimp 2.8, 'automatic requirement'

Are those correct ?

It is possible with the gimp_gmic plugin, if you can install it in your linux.
You can use HSV adjust (only changing the hue value) and it is scriptable.

[bugblatterbeast]

@Ofnuts: That is exactly what i wanted right now and even better. I didn't realize that my hue range was going from around 270 through zero to about 180. So just doing a division as I had in mind would have led to an undesirable result (edit: shift before operation would have been necessary).

@rich2005: Thank you very much for that hint. I am not using any fancy distribution, just boring Ubuntu with xfce (I'm lazy). G'MIC is available and seems highly interesting. I'll sure look into it in the future.

Issue is solved.

Thanks and regards!