@Override public void onMouseClicked(final MapMouseEvent e){
  if (!isTriggerMouseButton(e)) {
    return;
  }
  startDragPos=new DirectPosition2D();
  startDragPos.setLocation(e.getMapPosition());
}

@ Override public void onMouseClicked ( final MapMouseEvent e ) { if ( ! isTriggerMouseButton ( e ) ) { return ; } startDragPos = new DirectPosition2D ( ) ; startDragPos . setLocation ( e . getMapPosition ( ) ) ; }
zoom in by the currently set increment , with the map centred at the location ( in world coords ) of the mouse click
