void draw(Graphics2D g) {
   if (this == selected) {
     g.setColor(selectedColor);
     fillCircle(g, screenPos);
     g.setColor(color);
   } else drawCircle(g, screenPos);
   // drawText(g, screenPos, id);
 }
 private void fillCircle(Graphics2D g, Point2D loc) {
   int x = (int) (loc.getX() - circleRadius);
   int y = (int) (loc.getY() - circleRadius);
   g.fillOval(x, y, 2 * circleRadius, 2 * circleRadius);
 }