+ expose buffer_size parameter (default 0)

influences envelope used by placement detector 
  ( i.e. 'avoid_edges' parameter)

bindings/python/mapnik_map.cpp

@@ -96,6 +96,7 @@ void export_map()
       .add_property("height",&Map::getHeight, &Map::setHeight, "The height of the map.")
       .add_property("srs",make_function(&Map::srs,return_value_policy<copy_const_reference>()),
                     &Map::set_srs,"Spatial reference in proj4 format e.g. \"+proj=latlong +datum=WGS84\"")
+      .add_property("buffer_size", &Map::buffer_size,&Map::set_buffer_size,"The size of buffer around map in pixels")
       .add_property("background",make_function
                     (&Map::background,return_value_policy<copy_const_reference>()),
                     &Map::set_background, "The background color of the map.")

include/mapnik/map.hpp

@@ -41,22 +41,22 @@ namespace mapnik
 
         enum aspect_fix_mode 
         {
-            /* grow the width or height of the specified geo bbox to fill the map size. default behaviour. */
-            GROW_BBOX,
-            /* grow the width or height of the map to accomodate the specified geo bbox. */
-            GROW_CANVAS,
-            /* shrink the width or height of the specified geo bbox to fill the map size. */
-            SHRINK_BBOX,
-            /* shrink the width or height of the map to accomodate the specified geo bbox. */
+           // grow the width or height of the specified geo bbox to fill the map size. default behaviour.
+           GROW_BBOX,
+           // grow the width or height of the map to accomodate the specified geo bbox.
+           GROW_CANVAS,
+           // shrink the width or height of the specified geo bbox to fill the map size. 
+           SHRINK_BBOX,
+           // shrink the width or height of the map to accomodate the specified geo bbox.
             SHRINK_CANVAS,
-            /* adjust the width of the specified geo bbox, leave height and map size unchanged */
-            ADJUST_BBOX_WIDTH,
-            /* adjust the height of the specified geo bbox, leave width and map size unchanged */
+           // adjust the width of the specified geo bbox, leave height and map size unchanged
+           ADJUST_BBOX_WIDTH,
+           // adjust the height of the specified geo bbox, leave width and map size unchanged
             ADJUST_BBOX_HEIGHT,
-            /* adjust the width of the map, leave height and geo bbox unchanged */
-            ADJUST_CANVAS_WIDTH,
-            /* adjust the height of the map, leave width and geo bbox unchanged */
-            ADJUST_CANVAS_HEIGHT
+           // adjust the width of the map, leave height and geo bbox unchanged
+           ADJUST_CANVAS_WIDTH,
+           //adjust the height of the map, leave width and geo bbox unchanged 
+           ADJUST_CANVAS_HEIGHT
         };
     private:
         static const unsigned MIN_MAPSIZE=16;
@@ -64,13 +64,14 @@ namespace mapnik
         unsigned width_;
         unsigned height_;
         std::string  srs_;
+        int buffer_size_;
         boost::optional<Color> background_;
         std::map<std::string,feature_type_style> styles_;
         std::map<std::string,FontSet> fontsets_;
         std::vector<Layer> layers_;
         aspect_fix_mode aspectFixMode_;
         Envelope<double> currentExtent_;
-
+        
     public:
 
         typedef std::map<std::string,feature_type_style>::const_iterator const_style_iterator;
@@ -249,6 +250,17 @@ namespace mapnik
          */
         boost::optional<Color> const& background() const;
 
+        /*! \brief Set buffer size 
+         *  @param buffer_size Buffer size in pixels.
+         */
+        
+        void set_buffer_size(int buffer_size);
+        
+       /*! \brief Get the map buffer size 
+         *  @return Buffer size as int
+         */
+        int buffer_size() const;
+        
         /*! \brief Zoom the map at the current position.
          *  @param factor The factor how much the map is zoomed in or out.
          */

src/agg_renderer.cpp

@@ -113,7 +113,7 @@ namespace mapnik
         t_(m.getWidth(),m.getHeight(),m.getCurrentExtent(),offset_x,offset_y),
         font_engine_(),
         font_manager_(font_engine_),
-        detector_(Envelope<double>(-64, -64, m.getWidth() + 64 ,m.getHeight() + 64)),
+        detector_(Envelope<double>(-m.buffer_size(), -m.buffer_size(), m.getWidth() + m.buffer_size() ,m.getHeight() + m.buffer_size())),
         ras_ptr(new rasterizer)
    {
       boost::optional<Color> bg = m.background();

src/cairo_renderer.cpp

@@ -475,7 +475,7 @@ namespace mapnik
         font_engine_(new freetype_engine()),
         font_manager_(*font_engine_),
         face_manager_(font_engine_,font_manager_),
-        detector_(Envelope<double>(-64 ,-64, m.getWidth() + 64 ,m.getHeight() + 64))
+        detector_(Envelope<double>(-m.buffer_size() ,-m.buffer_size() , m.getWidth() + m.buffer_size() ,m.getHeight() + m.buffer_size()))
    {
 #ifdef MAPNIK_DEBUG
       std::clog << "scale=" << m.scale() << "\n";

src/load_map.cpp

@@ -127,6 +127,12 @@ namespace mapnik
                 }
 
                 map.set_srs( get_attr(map_node, "srs", map.srs() ));
+
+                optional<unsigned> buffer_size = get_opt_attr<unsigned>(map_node,"buffer_size");
+                if (buffer_size)
+                {
+                   map.set_buffer_size(*buffer_size);
+                }
             }
             catch (const config_error & ex)
             {
@@ -864,7 +870,14 @@ namespace mapnik
                    get_attr<label_placement_e>(sym, "placement", POINT_PLACEMENT);
                 shield_symbol.set_label_placement( placement );
 
-
+               // don't render shields around edges
+                optional<boolean> avoid_edges =
+                   get_opt_attr<boolean>(sym, "avoid_edges");
+                if (avoid_edges)
+                {
+                   shield_symbol.set_avoid_edges( *avoid_edges);
+                }
+                
                 // halo fill and radius
                 optional<Color> halo_fill = get_opt_attr<Color>(sym, "halo_fill");
                 if (halo_fill)

src/map.cpp

@@ -35,18 +35,21 @@ namespace mapnik
         : width_(400),
           height_(400),
           srs_("+proj=latlong +datum=WGS84"),
+          buffer_size_(0),
           aspectFixMode_(GROW_BBOX) {}
     
     Map::Map(int width,int height, std::string const& srs)
         : width_(width),
           height_(height),
           srs_(srs),
+          buffer_size_(0),
           aspectFixMode_(GROW_BBOX) {}
    
     Map::Map(const Map& rhs)
         : width_(rhs.width_),
           height_(rhs.height_),
           srs_(rhs.srs_),
+          buffer_size_(rhs.buffer_size_),
           background_(rhs.background_),
           styles_(rhs.styles_),
           layers_(rhs.layers_),
@@ -59,6 +62,7 @@ namespace mapnik
         width_=rhs.width_;
         height_=rhs.height_;
         srs_=rhs.srs_;
+        buffer_size_ = rhs.buffer_size_;
         background_=rhs.background_;
         styles_=rhs.styles_;
         layers_=rhs.layers_;
@@ -213,11 +217,21 @@ namespace mapnik
         return srs_;
     }
     
-    void Map::set_srs(std::string const& srs)
-    {
-        srs_ = srs;
-    }
-  
+   void Map::set_srs(std::string const& srs)
+   {
+      srs_ = srs;
+   }
+   
+   void Map::set_buffer_size( int buffer_size)
+   {
+      buffer_size_ = buffer_size;
+   }
+
+   int Map::buffer_size() const
+   {
+      return buffer_size_;
+   }
+   
    boost::optional<Color> const& Map::background() const
    {
       return background_;