docs: @Override
      protected void paintComponent(Graphics g) {
          updateLocation();
          if(highligted){
              g.setColor(Color.BLUE);
          }
          else{
              g.setColor(default_color);
          }
          int c = (int)(panel_size/2);
  
          if(cluster.getId()>=0)
              g.drawString("C"+(int)cluster.getId(),c,c);
          
          g.drawOval(0, 0, panel_size, panel_size);
  
          if(direction!=null){
              double length = Math.sqrt(Math.pow(direction[0], 2) + Math.pow(direction[1], 2));
              g.drawLine(c, c, c+(int)((direction[0]/length)*panel_size), c+(int)((direction[1]/length)*panel_size));
          }
  
          updateTooltip();
          
  
      }