float-rgb2hsl/index.js

converts [R,G,B] to [H,S,L]

module.exports = rgb2hsl
function rgb2hsl (rgb) {
  var r = rgb[0],
    g = rgb[1],
    b = rgb[2],
    min = Math.min(r, g, b),
    max = Math.max(r, g, b),
    delta = max - min,
    h, s, l

  if (max === min) {
    h = 0
  } else if (r === max) {
    h = (g - b) / delta
  } else if (g === max) {
    h = 2 + (b - r) / delta
  } else if (b === max) {
    h = 4 + (r - g) / delta
  }

  h = Math.min(h * 60, 360)

  if (h < 0) {
    h += 360
  }

  l = (min + max) / 2

  if (max === min) {
    s = 0
  } else if (l <= 0.5) {
    s = delta / (max + min)
  } else {
    s = delta / (2 - max - min)
  }

  return [h / 360, s, l]
}