color-rgb-to-hsv

color-rgb-to-hsv is a compiled Lisp function in `color.el'.

(color-rgb-to-hsv RED GREEN BLUE)

Convert RGB color components to HSV.
RED, GREEN, and BLUE should each be numbers between 0.0 and 1.0,
inclusive. Return a list (HUE SATURATION VALUE), where HUE is
in radians and both SATURATION and VALUE are between 0.0 and 1.0,
inclusive.