code: public void setZoom(int zoom)
      {
          zoomChanging = true;
          mainMap.setZoom(zoom);
          miniMap.setZoom(mainMap.getZoom() + 4);
          if (sliderReversed)
          {
              zoomSlider.setValue(zoomSlider.getMaximum() - zoom);
          }
          else
          {
              zoomSlider.setValue(zoom);
          }
          zoomChanging = false;
      }
docs: Set the current zoomlevel for the main map. The minimap will be updated accordingly
  @param zoom the new zoom level