RandomDissolveで表示を切り替え

class RandomDissolve extends JComponent implements ActionListener {
  private static final int STAGES = 16;
  private final Random rnd = new Random();
  private final Timer animator;
  private final transient BufferedImage image1;
  private final transient BufferedImage image2;
  private transient BufferedImage buf;
  private boolean mode = true;
  private int currentStage;
  private int[] src;
  private int[] dst;
  private int[] step;

  protected RandomDissolve(BufferedImage i1, BufferedImage i2) {
    super();
    this.image1 = i1;
    this.image2 = i2;
    this.buf = copyImage(mode ? image2 : image1);
    animator = new Timer(50, this);
  }

  private boolean nextStage() {
    return currentStage > 0 && copyNextStage();
  }

  @SuppressWarnings("PMD.AvoidArrayLoops")
  private boolean copyNextStage() {
    currentStage -= 1;
    for (int i = 0; i < step.length; i++) {
      if (step[i] == currentStage) {
        src[i] = dst[i];
      }
    }
    return true;
  }

  private static BufferedImage copyImage(BufferedImage image) {
    int w = image.getWidth();
    int h = image.getHeight();
    BufferedImage result = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = result.createGraphics();
    g2.drawRenderedImage(image, null);
    g2.dispose();
    return result;
  }

  private static int[] getData(BufferedImage image) {
    WritableRaster wr = image.getRaster();
    DataBufferInt dbi = (DataBufferInt) wr.getDataBuffer();
    return dbi.getData();
    // return ((DataBufferInt) image.getRaster().getDataBuffer()).getData();
  }

  public void animationStart() {
    currentStage = STAGES;
    buf = copyImage(mode ? image2 : image1);
    src = getData(buf);
    dst = getData(copyImage(mode ? image1 : image2));
    step = new int[src.length];
    mode ^= true;
    for (int i = 0; i < step.length; i++) {
      step[i] = rnd.nextInt(currentStage);
    }
    animator.start();
  }

  @Override protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setPaint(getBackground());
    g2.fillRect(0, 0, getWidth(), getHeight());
    g2.drawImage(buf, 0, 0, buf.getWidth(), buf.getHeight(), this);
    g2.dispose();
  }

  @Override public void actionPerformed(ActionEvent e) {
    if (nextStage()) {
      repaint();
    } else {
      animator.stop();
    }
  }
}