Api changes between v2.3 and v3.0

Removed

• Support for -ansi flag / non-c++11 compile. Starting at 3.x a compiler that recognizes -std=c++11 is required.
• Removed paths-from-xml option from the <Map> XML parser (https://github.com/mapnik/mapnik/issues/1893)
• ExpressionFormat in TextSymbolizer. Just use Format which now supports expressions for all properties (For now ExpressionFormat is deprecated and will be parsed automatically into Format).
• bilinear8 (raster scaling option) was obsolete and therefore removed.
• blend method removed from Image object in python bindings. The same actions can be accomplished with the composite function and src_over method.
• background property in python bindings has been removed, added the fill method to replace all its functionality.

Changed

• Made clip:false in all symbolizers (previous default was clip:true) - https://github.com/mapnik/mapnik/issues/2146
• In C++ mapnik::Map::addLayer was changed to mapnik::Map::add_layer
• In C++ mapnik::Map::removeLayer was changed to mapnik::Map::remove_layer
• In C++ mapnik::Map::getLayer was changed to mapnik::Map::get_layer
• Changed polygon_pattern_symbolizer to default to global rather than local for the alignment.
• CSV plugin now parses and stores the strings of "true", and "false" as boolean types (rather than strings) - https://github.com/mapnik/mapnik/issues/1540
• TextSymbolizer line wrapping behavior has now changed: previously line wrapping only happened on ascii whitespace (if wrap-character was not provided) but now it happens on any valid wrapping characters as determined by the default locale and the behavior of the ICU::BreakIterator(http://userguide.icu-project.org/boundaryanalysis).
• wrap-character property for TextSymbolizer should behave similarly as 2.3 but the code to support it was completely re-written so there may be slight differences in render: https://github.com/mapnik/mapnik/issues/2333

Added

• MarkersSymbolizer now supports avoid-edges, offset, geometry-transform, simplify for line placement and two new placement options called vertex-last and vertex-first to place a single marker at the end or beginning of a path. Also clip is now respected when rendering markers on a LineString geometry.
• TextSymbolizer now supports smooth, simplify, halo-opacity, halo-comp-op, and halo-transform
• ShieldSymbolizer now supports smooth, simplify, halo-opacity, halo-comp-op, and halo-transform