code: function hcl2rgb(pixel) {
    const h = pixel[0];
    const c = pixel[1];
    const l = pixel[2];
  
    const a = Math.cos(h) * c;
    const b = Math.sin(h) * c;
  
    let y = (l + 16) / 116;
    let x = isNaN(a) ? y : y + a / 500;
    let z = isNaN(b) ? y : y - b / 200;
  
    y = Yn * lab2xyz(y);
    x = Xn * lab2xyz(x);
    z = Zn * lab2xyz(z);
  
    pixel[0] = xyz2rgb(3.2404542 * x - 1.5371385 * y - 0.4985314 * z);
    pixel[1] = xyz2rgb(-0.9692660 * x + 1.8760108 * y + 0.0415560 * z);
    pixel[2] = xyz2rgb(0.0556434 * x - 0.2040259 * y + 1.0572252 * z);
  
    return pixel;
  }
docs: Convert an HCL pixel into an RGB pixel.
  @param {Array<number>} pixel A pixel in HCL space.
  @return {Array<number>} A pixel in RGB space.