Vignetting with color

[boyanov]

The Vignetting function works very well, but it will be even better if I can change the color of the vignetting. It is at the moment either white (lightning the edges) or black (darkening the edges).

Below is an example of an image that a friend of mine processed with another app. As you can see, the edges are a shade of blue instead of just darkened.

I understand that this might not be a trivial thing to do.

Thanks a lot for the incredible work on this app!