Swing/DragHereIcon のバックアップ(No.4)

class DragHereIcon implements Icon {
  private static int ICON_SIZE = 100;
  private static float BORDER_WIDTH = 8f;
  private static float SLIT_WIDTH = 8f;
  private static int ARC_SIZE = 16;
  private static int SLIT_NUM = 3;
  private static Shape BORDER = new RoundRectangle2D.Float(
    BORDER_WIDTH,BORDER_WIDTH,
    ICON_SIZE-2*BORDER_WIDTH-1,ICON_SIZE-2*BORDER_WIDTH-1,
    ARC_SIZE,ARC_SIZE);
  private static Font font = new Font(Font.MONOSPACED, Font.BOLD, ICON_SIZE);
  private static FontRenderContext frc = new FontRenderContext(null, true, true);
  //DOWNWARDS WHITE ARROW
  private static Shape ARROW = new TextLayout("\u21E9", font, frc).getOutline(null);
  //DOWNWARDS BLACK ARROW
  //private static Shape ARROW = new TextLayout("\u2B07", font, frc).getOutline(null);
  private static Color LINE_COLOR = Color.GRAY;
  @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);
    g2.translate(x, y);

    g2.setStroke(new BasicStroke(BORDER_WIDTH));
    g2.setPaint(LINE_COLOR);
    g2.draw(BORDER);

    g2.setStroke(new BasicStroke(SLIT_WIDTH));
    g2.setColor(UIManager.getColor("Panel.background"));

    int n = SLIT_NUM+1;
    int v = ICON_SIZE/n;
    int m = n*v;
    for(int i=1;i<n;i++) {
      int a = i*v;
      g2.drawLine(a,0,a,m);
      g2.drawLine(0,a,m,a);
    }

    //g2.drawLine(1*v,0*v,1*v,4*v);
    //g2.drawLine(2*v,0*v,2*v,4*v);
    //g2.drawLine(3*v,0*v,3*v,4*v);
    //g2.drawLine(0*v,1*v,4*v,1*v);
    //g2.drawLine(0*v,2*v,4*v,2*v);
    //g2.drawLine(0*v,3*v,4*v,3*v);

    g2.setPaint(LINE_COLOR);
    Rectangle2D b = ARROW.getBounds();
    Point2D p = new Point2D.Double(b.getX() + b.getWidth()/2d, b.getY() + b.getHeight()/2d);
    AffineTransform toCenterAT = AffineTransform.getTranslateInstance(
        ICON_SIZE/2d - p.getX(), ICON_SIZE/2d - p.getY());
    g2.fill(toCenterAT.createTransformedShape(ARROW));
    g2.translate(-x,-y);
    g2.dispose();
  }
  @Override public int getIconWidth()  {
    return ICON_SIZE;
  }
  @Override public int getIconHeight() {
    return ICON_SIZE;
  }
}