pure-color/convert/rgb2lab.js

Pure functions for color conversion and parsing

var rgb2xyz = require("./rgb2xyz");

function rgb2lab(rgb) {
  var xyz = rgb2xyz(rgb),
        x = xyz[0],
        y = xyz[1],
        z = xyz[2],
        l, a, b;

  x /= 95.047;
  y /= 100;
  z /= 108.883;

  x = x > 0.008856 ? Math.pow(x, 1/3) : (7.787 * x) + (16 / 116);
  y = y > 0.008856 ? Math.pow(y, 1/3) : (7.787 * y) + (16 / 116);
  z = z > 0.008856 ? Math.pow(z, 1/3) : (7.787 * z) + (16 / 116);

  l = (116 * y) - 16;
  a = 500 * (x - y);
  b = 200 * (y - z);

  return [l, a, b];
}

module.exports = rgb2lab;