message: Further optimized version.
diff: @@ -91,17 +91,15 @@ pub fn cmyk_to_rgb(input: &[u8]) -> Vec<u8> {
  let in_pixels = input[..4*count].chunks_exact(4);
  let out_pixels = output[..3*count].chunks_exact_mut(3);
  - let inv = 1.0/255.0;
  for (pixel, outp) in in_pixels.zip(out_pixels) {
  let c = 255 - u16::from(pixel[0]);
  let m = 255 - u16::from(pixel[1]);
  let y = 255 - u16::from(pixel[2]);
  let k = 255 - u16::from(pixel[3]);
  -
  // CMY -> RGB
  - let r = (k * c) as f32 * inv;
  - let g = (k * m) as f32 * inv;
  - let b = (k * y) as f32 * inv;
  + let r = (k * c) / 255;
  + let g = (k * m) / 255;
  + let b = (k * y) / 255;
  outp[0] = r as u8;
  outp[1] = g as u8;
  