migurski/TileStache — pull request #37 by sk1p (2012-03-21 01:29:51+00:00)
Title: Support for buffers around grid features (MapnikGrid)

Sometimes, representations of (point-)features on grid layers span multiple tiles. Without a buffer, they will only be interactive in the tile that contains the center of the feature.

This pull request adds a new parameter, buffer, to the MapnikGrid provider. The rendered area is then enlarged by this buffer in each direction, rendered, and only a GridView corresponding to the original tile size is encoded and returned.

There is room for improvement: the grid rendering code could use the same metatile code as used together with the built-in mapnik provider