@Test
  public void testTranslatedImage() {
    BufferedImage image = new BufferedImage(256, 256, BufferedImage.TYPE_BYTE_GRAY);
    Graphics g = image.createGraphics();
    g.setColor(Color.WHITE);
    g.fillRect(236, 236, 20, 20);
    g.setColor(new Color(80, 80, 80)); // A dark gray
    g.fillRect(216, 216, 20, 20);
    g.setColor(new Color(200, 200, 200)); // A light gray
    g.fillRect(216, 236, 20, 20);
    g.dispose();
    image = image.getSubimage(128, 128, 128, 128);
    CustomPaletteBuilder builder = new CustomPaletteBuilder(image, 256, 1, 1, 1);
    RenderedImage indexed = builder.buildPalette().getIndexedImage();
    assertTrue(indexed.getColorModel() instanceof IndexColorModel);
    IndexColorModel icm = (IndexColorModel) indexed.getColorModel();
    assertEquals(
        4,
        icm
            .getMapSize()); // Black background, white fill, light gray fill, dark gray fill = 4
                            // colors

    // check image not black
    ImageWorker iw = new ImageWorker(indexed).forceComponentColorModel().intensity();
    double[] mins = iw.getMinimums();
    double[] maxs = iw.getMaximums();
    boolean result = true;
    for (int i = 0; i < mins.length; i++) {
      result = mins[i] == maxs[i] ? false : result;
    }
    assertTrue(result);
  }