h , s , v = hue , saturation , value var cmax = Math . max ( r , Math . max ( g , b ) ) ; maximum of r , g , b var cmin = Math . min ( r , Math . min ( g , b ) ) ; minimum of r , g , b var diff = cmax - cmin ; diff of cmax and cmin .
var h = - 1 , s = - 1 ;