color-function(from origin-color channel1 channel2 channel3 / alpha)
# color-function: the color function you want to use (e.g. rgb, hsl, lab, lch)
# origin-color: the color you want to take the values from
# channel1, channel2, channel3: the color channels you want to use
# (e.g. red, green, blue, hue, saturation, lightness)
# alpha: optional alpha value for transparency