Swing/CompoundButton のバックアップ(No.1)

private static JComponent makeCompoundButton(final Dimension d) {
  JPanel p = new JPanel() {
    @Override public Dimension getPreferredSize() {
      return d;
    }
  };
  p.setLayout(new OverlayLayout(p));
  p.add(new CompoundButton(d, ButtonLocation.NOTH));
  p.add(new CompoundButton(d, ButtonLocation.SOUTH));
  p.add(new CompoundButton(d, ButtonLocation.EAST));
  p.add(new CompoundButton(d, ButtonLocation.WEST));
  p.add(new CompoundButton(d, ButtonLocation.CENTER));
  return p;
}

class CompoundButton extends JButton {
  protected final Color fc = new Color(100,150,255,200);
  protected final Color ac = new Color(230,230,230);
  protected final Color rc = Color.ORANGE;
  protected Shape shape;
  protected Shape base = null;
  private final ButtonLocation bl;
  private final Dimension dim;
  public CompoundButton(Dimension d, ButtonLocation bl) {
    super();
    this.dim = d;
    this.bl = bl;
    setIcon(new Icon() {
      @Override public void paintIcon(Component c, Graphics g, int x, int y) {
        Graphics2D g2 = (Graphics2D)g.create();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                  RenderingHints.VALUE_ANTIALIAS_ON);
        if(getModel().isArmed()) {
          g2.setColor(ac);
          g2.fill(shape);
        }else if(isRolloverEnabled() && getModel().isRollover()) {
          paintFocusAndRollover(g2, rc);
        }else if(hasFocus()) {
          paintFocusAndRollover(g2, fc);
        }else{
          g2.setColor(getBackground());
          g2.fill(shape);
        }
        g2.dispose();
      }
      @Override public int getIconWidth()  {
        return dim.width;
      }
      @Override public int getIconHeight() {
        return dim.height;
      }
    });
    setFocusPainted(false);
    setContentAreaFilled(false);
    setBackground(new Color(250, 250, 250));
    initShape();
  }
  @Override public Dimension getPreferredSize() {
    return dim;
  }
  protected void initShape() {
    if(!getBounds().equals(base)) {
      base = getBounds();
      float ww = getWidth() * 0.5f;
      float xx = ww * 0.5f;
      Shape inner = new Ellipse2D.Float(xx, xx, ww, ww);
      if(ButtonLocation.CENTER==bl) {
        shape = inner;
      }else{
        Shape outer = new Arc2D.Float(1, 1, getWidth()-2, getHeight()-2, bl.getStartDegree(), 90f, Arc2D.PIE);
        Area area = new Area(outer);
        area.subtract(new Area(inner));
        shape = area;
      }
    }
  }
  private void paintFocusAndRollover(Graphics2D g2, Color color) {
    g2.setPaint(new GradientPaint(0, 0, color,
                    getWidth()-1, getHeight()-1, color.brighter(), true));
    g2.fill(shape);
    g2.setColor(getBackground());
  }
  @Override protected void paintComponent(Graphics g) {
    initShape();
    super.paintComponent(g);
  }
  @Override protected void paintBorder(Graphics g) {
    Graphics2D g2 = (Graphics2D)g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
              RenderingHints.VALUE_ANTIALIAS_ON);
    g2.setColor(getForeground());
    g2.draw(shape);
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
              RenderingHints.VALUE_ANTIALIAS_OFF);
  }
  @Override public boolean contains(int x, int y) {
    //initShape();
    return shape.contains(x, y);
  }
}