Hello, Josm renders them and only uses it's own Java objects after reading the XML. There are two rendering phases: Collecting the styles to be rendered and then painting everything on the screen.
Here are some hints on where to get started: The generation of styles for a multipolygon is triggered here: > https://github.com/openstreetmap/josm/blob/7a780ca01e8b2b31fbfa243af1db37d032ba7853/src/org/openstreetmap/josm/gui/mappaint/ElemStyles.java#L367 Style collection (finding what needs to be drawn): > https://github.com/openstreetmap/josm/blob/7a780ca01e8b2b31fbfa243af1db37d032ba7853/src/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRenderer.java#L1837 We inherit the style of the surrounding ways from the multipolygon. That way, multipolygon borders can be rendered like normal ways. > https://github.com/openstreetmap/josm/blob/7a780ca01e8b2b31fbfa243af1db37d032ba7853/src/org/openstreetmap/josm/gui/mappaint/ElemStyles.java#L203 Old (deprecated) polygons inherit their style from the outer lines: > https://github.com/openstreetmap/josm/blob/7a780ca01e8b2b31fbfa243af1db37d032ba7853/src/org/openstreetmap/josm/gui/mappaint/ElemStyles.java#L301 And finally the real rendering of the area (borders are rendered since their line segments got the style from the multipolygon). > https://github.com/openstreetmap/josm/blob/7a780ca01e8b2b31fbfa243af1db37d032ba7853/src/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRenderer.java#L615 Michael Am 03.01.2016 um 23:24 schrieb Mikoláš Štrajt: > Hello, > I am developing my own rendering software and I struggled on decoding > multipolygon relations. It seems to be bit tricky. I tried to found some > info about it, but all I found is this wiki page: http://wiki.openstreetmap. > org/wiki/Relation:multipolygon/Algorithm > > Can you point to some example of code decoding multipolygons? I would > especially like something that will be written with renderer in mind (ie > source code is part of some renderer). > > Note that my software decodes OSM XML file itself, I don't want to use > PostGIS as backend. > > > > _______________________________________________ > dev mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/dev > _______________________________________________ dev mailing list [email protected] https://lists.openstreetmap.org/listinfo/dev
