/** Flips the image from top to bottom */
  public static void flipVertical(ImageInt16 img) {
    int h2 = img.height / 2;

    for (int y = 0; y < h2; y++) {
      int index1 = img.getStartIndex() + y * img.getStride();
      int index2 = img.getStartIndex() + (img.height - y - 1) * img.getStride();

      int end = index1 + img.width;

      while (index1 < end) {
        int tmp = img.data[index1];
        img.data[index1++] = img.data[index2];
        img.data[index2++] = (short) tmp;
      }
    }
  }
  /**
   * Fills the whole image with the specified pixel value
   *
   * @param img An image.
   * @param value The value that the image is being filled with.
   */
  public static void fill(ImageInt16 img, int value) {
    final int h = img.getHeight();
    final int w = img.getWidth();

    short[] data = img.data;

    for (int y = 0; y < h; y++) {
      int index = img.getStartIndex() + y * img.getStride();
      for (int x = 0; x < w; x++) {
        data[index++] = (short) value;
      }
    }
  }
  /**
   * Sets each value in the image to a value drawn from an uniform distribution that has a range of
   * min <= X < max.
   */
  public static void randomize(ImageInt16 img, Random rand, int min, int max) {
    final int h = img.getHeight();
    final int w = img.getWidth();

    int range = max - min;

    short[] data = img.data;

    for (int y = 0; y < h; y++) {
      int index = img.getStartIndex() + y * img.getStride();
      for (int x = 0; x < w; x++) {
        data[index++] = (short) (rand.nextInt(range) + min);
      }
    }
  }