# File lib/cairo/color.rb, line 116 def to_cmyk cmy = [1.0 - @red, 1.0 - @green, 1.0 - @blue] key_plate = cmy.min if key_plate < 1.0 one_k = 1.0 - key_plate cmyk = cmy.collect {|value| (value - key_plate) / one_k} + [key_plate] else cmyk = [0, 0, 0, key_plate] end cmyka = cmyk + [@alpha] CMYK.new(*cmyka) end