@Override
  public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
    messageDigest.update((ID + center + Arrays.hashCode(vignetteColor) + vignetteStart + vignetteEnd).getBytes(CHARSET));
  }
Performs a vignetting effect, fading out the image at the edges
The directional intensity of the vignetting,
with a default of x = 0.5, y = 0.5, start = 0, end = 0.75
transformations/src/main/java/jp/wasabeef/glide/transformations/gpu/VignetteFilterTransformation.java