RGB crossFade using millis()

Hi everybody, how are you?

Do you have any idea how to use this fantastic sketch with the millis()?

-> https://www.arduino.cc/en/Tutorial/ColorCrossfader

The algorithm I am writing foresees that at each call the function makes a crossfade between one color to another with an always different random time.

Everything is based on this sketch found on the forum, but now I have to make it independent of the delay ().

Thanks to all in advance

but now I have to make it independent of the delay ().

See my
http://www.thebox.myzen.co.uk/Tutorial/State_Machine.html
Or Robin2's several things at once

Thank you for your reply!