Convert color systems

hex2rgb.coffee

hex2rgb = (hexcode) ->
  # rgbに変換する
  result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hexcode);
  if result is null
    console.log "error!"
    return
  
  [r,g,b] = [parseInt(result[1], 16), parseInt(result[2], 16), parseInt(result[3], 16)]
  return [r,g,b]

hsv2rgb.coffee

hsv2rgb = (h,s,v) ->
  if h < 0
    r = 0
    g = 0
    b = 0
  else
    h_dash = h / 60
    x = s * (1 - Math.abs(h_dash % 2 - 1))
    if h_dash < 1
      [r,g,b] = [s,x,0]
    else if h_dash < 2
      [r,g,b] = [x,s,0]
    else if h_dash < 3
      [r,g,b] = [0,s,x]
    else if h_dash < 4
      [r,g,b] = [0,x,s]
    else if h_dash < 5
      [r,g,b] = [x,0,s]
    else if h_dash < 6
      [r,g,b] = [s,0,x]
    else
        console.log '変換エラー'
        return
  r += (v-s)
  g += (v-s)
  b += (v-s)
  r *= 255
  g *= 255
  b *= 255
  return [r,g,b]

rgb2hsv.coffee

rgb2hsv = (r,g,b) ->
  # rgb to hsv
  r = r / 255
  g = g / 255
  b = b / 255
  
  max_v = Math.max(Math.max(r,g), b)
  min_v = Math.min(Math.min(r,g), b)  
  v = max_v
  s = max_v - min_v
  if min_v == max_v
    h = -1
  else if min_v == b
    h = 60 * (g-r)/s + 60
  else if min_v == r
    h = 60 * (b-g)/s + 180
  else
    h = 60 * (r-b)/s + 300
  return [h,s,v]