Earlier today I tested krita5’s gradient resource. Then I thought of cross-channel color adjustment while using the Gradientmap filter.
Gradientmap has always mapped according to lightness channels. But what if it could map saturation, alpha, red, green and blue? We can apply a gradient to the obvious properties with the filter layer, and then blend with the original layer. That should be useful.
In terms of implementation, the other channels are also grayscale images. We only need to obtain the corresponding channel, which is not far away.