JProgressBarのNimbusLookAndFeelにおける不確定状態アニメーションを変更する

UIDefaults d = new UIDefaults();
d.put("ProgressBar[Enabled+Indeterminate].foregroundPainter",
      new AbstractRegionPainter() {
  // ...
  private final PaintContext ctx = new PaintContext(
      new Insets(5, 5, 5, 5), new Dimension(29, 19), false);
  @Override public void doPaint(
        Graphics2D g, JComponent c, int width, int height,
        Object[] extendedCacheKeys) {
    path = decodePath1();
    g.setPaint(color17);
    g.fill(path);
    rect = decodeRect3();
    g.setPaint(decodeGradient5(rect));
    g.fill(rect);
    rect = decodeRect4();
    g.setPaint(decodeGradient6(rect));
    g.fill(rect);
  }

  @Override public PaintContext getPaintContext() {
    return ctx;
  }
  // ...
});
progress = new JProgressBar(model);
progress.putClientProperty("Nimbus.Overrides", d);