compositing is not yet supported in mapnik on the building symbolizer - https://github.com/mapnik/mapnik/issues/1355
compositing is not yet supported in mapnik on the building symbolizer - https://github.com/mapnik/mapnik/issues/1355

florianf/mapnik-reference,mapnik/mapnik-reference,mojodna/mapnik-reference,mapnik/mapnik-reference,florianf/mapnik-reference,mapycz/mapnik-reference,mojodna/mapnik-reference,CartoDB/mapnik-reference,mapycz/mapnik-reference,gravitystorm/mapnik-reference,mapnik/mapnik-reference,gravitystorm/mapnik-reference,CartoDB/mapnik-reference