CoffeeScript RGB ⇔ HSV

gistfile1.coffee

# Returns [hue, sat, value] when given red, green, blue. All 6 values are between 0...1.
rgb2hsv = (r, g, b) ->
  v = Math.max r, g, b
  x = v - Math.min r, g, b
  [
    ( if x is 0
        0
      else if v is r
        (g - b) / x
      else if v is g
      	(b - r) / x + 2
      else
      	(r - g) / x + 4
    ) %% 6 / 6
    if v is 0
    	0
    else
       x / v
    v
  ]

# Returns [red, green, blue] when given hue, sat, value. All 6 values are between 0...1.
hsv2rgb = (h, s, v) ->
  c = v * s
  h = h * 6
  x = c * (1 - Math.abs h % 2 - 1)
  [r, g, b] = 
    if h < 1
      [c, x, 0]
    else if h < 2
      [x, c, 0]
    else if h < 3
      [0, c, z]
    else if h < 4
      [0, x, c]
    else if h < 5
      [x, 0, c]
    else
      [c, 0, x]
  m = v - c
  [r + m, g + m, b + m]