GeneralPathなどで星型図形を作成する

class StarPanel1 extends JPanel {
  @Override protected void paintComponent(Graphics g) {
    Graphics2D g2 = (Graphics2D) g.create();
    int w = getWidth();
    int h = getHeight();
    GeneralPath p = new GeneralPath();
    p.moveTo(-w / 4f, -h / 12f);
    p.lineTo(w / 4f, -h / 12f);
    p.lineTo(-w / 6f, h / 4f);
    p.lineTo(0f, -h / 4f);
    p.lineTo(w / 6f, h / 4f);
    p.closePath();
    g2.translate(w / 2, h / 2);
    g2.setColor(Color.YELLOW);
    g2.fill(p);
    g2.setColor(Color.BLACK);
    g2.draw(p);
    g2.dispose();
  }
}

class StarIcon2 implements Icon {
  private static final int R1 = 20;
  private static final int R2 = 40;
  private static final int VC = 5; // 16;
  private final AffineTransform at;
  private final Shape star;
  public StarIcon2() {
    double agl = 0d;
    double add = 2 * Math.PI / (VC * 2);
    Path2D p = new Path2D.Double();
    p.moveTo(R2 * 1, R2 * 0);
    for (int i = 0; i < VC * 2 - 1; i++) {
      agl += add;
      if (i % 2 == 0) {
        p.lineTo(R1 * Math.cos(agl), R1 * Math.sin(agl));
      } else {
        p.lineTo(R2 * Math.cos(agl), R2 * Math.sin(agl));
      }
    }
    p.closePath();
    at = AffineTransform.getRotateInstance(-Math.PI / 2, R2, 0);
    star = new Path2D.Double(p, at);
  }

  @Override public int getIconWidth() {
    return 2 * R2;
  }

  @Override public int getIconHeight() {
    return 2 * R2;
  }

  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.translate(x, y);
    g2.setPaint(Color.YELLOW);
    g2.fill(star);
    g2.setPaint(Color.BLACK);
    g2.draw(star);
    g2.dispose();
  }
}