code: public static Pair<Bitmap, Bitmap> splitHorizontally(@NonNull final Bitmap bitmap) {
          return splitHorizontally(bitmap, bitmap.getHeight() / 2);
      }
docs: Splits a specific bitmap horizontally at half.
  
  @param bitmap
  The bitmap, which should be split, as an instance of the class {@link Bitmap}. The
  bitmap may not be null
  @return A pair, which contains the two bitmaps, which the original bitmap has been split
  into, as an instance of the class Pair