Map view tile size is what defines the
      rendering, both in vector and raster maps.
      
      We have examples with raster tile sources in Mapsforge samples
      app, e.g. 
DownloadLayerViewer.
    
    There a fixed tile size 256px is used, as that is provided by the
    tile source (see 
here):
    
    
this.mapView
.getModel()
.displayModel
.setFixedTileSize(
256);
    
    If you remove that line, then the map view tile size will be
    auto-calculated based on device dpi (like in vector maps) and so the
    raster tiles would appear bigger (though a bit blurry).