Api changes between v2.1 and v2.2

Removed

• geos and kismet plugins were removed (#1809,#1833)
• ltdl, cairomm, and libsigc++ dependencies were removed
• Removed the bind option for datasources (#1654)

Changed

• The max_size and initial_size options for the PostGIS datasource impact behavior for a single, global pool of postgresql connections. In Mapnik >= 2.2.0, when set for any layer, if the max_size or initial_size is larger than the default (10 for max_size and 1 for initial_size) or any previously set value then the global value will be increased. In older Mapnik only the values set in the first layer would be respected. Ticket
• Proj4 init errors due to invalid srs values will now cause exceptions when a map is loaded from XML as well as when encountered during rendering. The latter will very unlikely happen now that validation is done at map loading time. Previously errors were not reported except at render time and only as warnings printed to stderr (#646)
• <Filter>[attr] != ''</Filter> now matches only empty strings. This syntax previously matched both empty strings and nulls but this behavior was unintended and buggy given that Mapnik has supported a null type since 2.0.0. If you wish to filter out all attr values that are not empty strings or null or false boolean type then you can do <Filter>[attr]</Filter> or <Filter>[attr] != '' and [attr] != null and [attr] != false</Filter> No longer the case for 2.2 release, due to backwards compatibility fix as per https://github.com/mapnik/mapnik/issues/1859

Added

• Added Logging framework documentation synced with 2.2 status: https://github.com/mapnik/mapnik/wiki/Logging
• DebugSymbolizer - if used it will draw the invisible collision boxes collected up to that point in rendering the stylesheet. Also can be used to draw all verticies of geometries with mode=vertex (#1366)
• Added new mapnik-config flags: --all-flags, --defines, --git-describe, --includes, --dep-includes, --cxxflags, --cxx (#1443)
• Added support for reading images from in memory streams (#1805) in c++ and python.
• Added text-halo-rasterizer property. Set to fast for lower quality but faster halo rendering (#1298) which matched new default method when radius is < 1.
• Added C++ api for overriding scale_denominator to enable rendering at fixed scale (#1582)
• Added Layer buffer-size that can be used to override Map buffer-size (#1566)
• Added mapnik::map_request class, a special object to allow passing mutable map objects to renderer (#1737)
• Added is_solid method to python mapnik.Image and mapnik.ImageView classes (#1728)
• Added support for controlling rendering behavior of markers on multi-geometries marker-multi-policy (#1555,#1573)
• Added alternative PNG/ZLIB implementation (miniz) that can be enabled with e=miniz (#1554)
• Added support for setting zlib Z_FIXED strategy with format string: png:z=fixed
• Added ability to re-use mapnik::image_32 and mapnik::grid by exposing a clear method (#1571)
• Added support for writing RGB (no A) png images by using the format string of png:t=0 (#1559)