I think I don’t fully understand this request, but I’ll give it a try.
You want to adjust color with 4 encoders, one for R, one for G, one for B and one for alpha. All 4 encoders should display in its ring, the color resultant of the adjustment made with the encoders.
In this case this would be necessary to be implemented with each different software separately. I don’t know if difficult to accomplish, but surely tedious and application-specific.
We have a feature for the encoders feedback called Value To Color, which allows you to re-set the encoder ring’s color, with a CC message on channel 16 (the same CC you configured for the encoder). For this you have 128 colors to choose from, which span the Hue and Saturation color space. The next firmware will include a feature calld Value to Intensity which will work similarly and allow you to change the brightness for each ring and button.
If this color table does not suit you, you can use a custom palette recompiling our firmware!
there is a guide for this on this forum
and someone already did it
So, if you get Bome MIDI translator, to translate the color in your software, to a value between 0 and 127 pointing to the correct color in the table, it sounds like you could achieve your goal, (if my assumptions are correct )