Migrating a webapp from Google Maps API V3 to OSM + Leaflet, which displays custom data that consists of lots of lines and points, on a background map.
When this custom data is drawn by Leaflet on the fly from geoJson files, the map tends to become less responsive on slow machines (zoom and pan take forever).
The custom data is pretty static (it doesn't change often), so it would make sense to pre-render it as transparent image tiles that would be displayed on top of the map. This is how KML files are rendered on Google Maps and it works very well.
So the question is this: how to generate transparent tiles from geoJson files and reference them in Leaflet (instead of displaying geoJson data on the fly)?