Jiri Drbalek

I have mixed feelings whether such logic belongs to Mapnik. It's similar to the tiling logic. Mapnik knows nothing about tiles. Mapnik gets bounding box of the map on input...

I will emphasize that there is `mapnik::image::painted` flag (or `Image.painted` in Python) to know whether a tile is empty or not. This flag is being set to true when a...

@springmeyer - given the fact that corresponding carto pull requests for #62 and #61 can never land and according to importance of mapnik-reference for non-carto users, what about to merge...

I see two options. First the simpler one. You can place the overlay box by ShieldSymbolizer with `placement="point` to the center of the map and use `placement-type="list"` to define positions...

@kocio-pl This is possible already by [render-time variables](https://github.com/mapnik/mapnik/issues/2553) . `@zoom` variable [is implemented in tilelive-mapnik](https://github.com/mapbox/tilelive-mapnik/commit/62339a2f49a3449372a33a8f481bde9194030241).

> Are there any new styling properties or changes to styling properties? I know of these: https://github.com/mapnik/mapnik/pull/3715, https://github.com/mapnik/mapnik/pull/3782, https://github.com/mapnik/mapnik/pull/3512, https://github.com/mapnik/mapnik/pull/3596, https://github.com/mapnik/mapnik/pull/3474.

It really needs some better description: https://github.com/gravitystorm/openstreetmap-carto/pull/3295#issuecomment-404821992