+ make width,height and type optinal in following

symbolizers: 
    * point_symbolizer
    * shield_symbolizer
    * line_pattern_symbolizer
    * polygon_pattern_symbolizer

src/load_map.cpp

@@ -24,6 +24,7 @@
 
 #include <mapnik/version.hpp>
 #include <mapnik/image_reader.hpp>
+#include <mapnik/image_util.hpp>
 #include <mapnik/color.hpp>
 #include <mapnik/color_factory.hpp>
 #include <mapnik/filter_factory.hpp>
@@ -652,6 +653,7 @@ namespace mapnik
          optional<std::string> file =  get_opt_attr<string>(sym, "file");
          optional<std::string> base =  get_opt_attr<string>(sym, "base");
          optional<std::string> type =  get_opt_attr<string>(sym, "type");
+          
          optional<boolean> allow_overlap =
             get_opt_attr<boolean>(sym, "allow_overlap");
          optional<float> opacity =
@@ -660,8 +662,32 @@ namespace mapnik
          optional<unsigned> width = get_opt_attr<unsigned>(sym, "width");
          optional<unsigned> height = get_opt_attr<unsigned>(sym, "height");
          
-            if (file && type && width && height)
+         //   
+         if (file)
          {
+            if (!type)
+            {
+               type = type_from_filename(*file);
+            }     
+            
+            if (!width || !height)
+            {
+               try 
+               {
+                  std::auto_ptr<ImageReader> reader(get_image_reader(*file));
+                  if (reader.get())
+                  {
+                     if (!width) width = reader->width();
+                     if (!height) height = reader->height();
+                     BOOST_ASSERT(*width > 0 && *height > 0);
+                  }
+               }
+               catch (...)
+               {
+                  std::cerr << "Exception caught while loading image:" << *file << std::endl;
+               }   
+            }
+               
             try
             {
                if( base )
@@ -678,7 +704,8 @@ namespace mapnik
                   *file = ensure_relative_to_xml(file);
                }
 #ifdef MAPNIK_DEBUG
-                   else {
+               else 
+               {
                   std::clog << "\nFound relative paths in xml, leaving unchanged...\n";
                }
 #endif
@@ -709,16 +736,16 @@ namespace mapnik
             }
 
          }
-            else if (file || type || width || height)
+         //else if (file || type || width || height)
-            {
+         //{
-                std::ostringstream os;
+         //   std::ostringstream os;
-                os << "Missing required attributes: ";
+         //  os << "Missing required attributes: ";
-                if ( ! file ) os << "file ";
+         //  if ( ! file ) os << "file ";
-                if ( ! type ) os << "type ";
+         //  if ( ! type ) os << "type ";
-                if ( ! width ) os << "width ";
+         //  if ( ! width ) os << "width ";
-                if ( ! height ) os << "height ";
+         //  if ( ! height ) os << "height ";
-                throw config_error( os.str() );
+         //  throw config_error( os.str() );
-            }
+         //}
          else
          {
             rule.append(point_symbolizer());
@@ -737,9 +764,32 @@ namespace mapnik
       {
          std::string file = get_attr<string>(sym, "file");
          optional<std::string> base = get_opt_attr<string>(sym, "base");
-            std::string type = get_attr<string>(sym, "type");
+         optional<std::string> type = get_attr<string>(sym, "type");
-            unsigned width = get_attr<unsigned>(sym, "width");
+         optional<unsigned> width = get_attr<unsigned>(sym, "width");
-            unsigned height = get_attr<unsigned>(sym, "height");
+         optional<unsigned> height = get_attr<unsigned>(sym, "height");
+         
+         if (!type)
+         {
+            type = type_from_filename(file);
+         }     
+            
+         if (!width || !height)
+         {
+            try 
+            {
+               std::auto_ptr<ImageReader> reader(get_image_reader(file));
+               if (reader.get())
+               {
+                  if (!width) width = reader->width();
+                  if (!height) height = reader->height();
+                  BOOST_ASSERT(*width > 0 && *height > 0);
+               }
+            }
+            catch (...)
+            {
+               std::cerr << "Exception caught while loading image:" << file << std::endl;
+            }   
+         }
          
          try
          {
@@ -762,7 +812,7 @@ namespace mapnik
 #endif
 
 
-               line_pattern_symbolizer symbol(file,type,width,height);
+            line_pattern_symbolizer symbol(file,*type,*width,*height);
             rule.append(symbol);
          }
          catch (ImageReaderException const & ex )
@@ -793,9 +843,32 @@ namespace mapnik
       {
          std::string file = get_attr<string>(sym, "file");
          optional<std::string> base = get_opt_attr<string>(sym, "base");
-            std::string type = get_attr<string>(sym, "type");
+         optional<std::string> type = get_attr<string>(sym, "type");
-            unsigned width = get_attr<unsigned>(sym, "width");
+         optional<unsigned> width = get_attr<unsigned>(sym, "width");
-            unsigned height = get_attr<unsigned>(sym, "height");
+         optional<unsigned> height = get_attr<unsigned>(sym, "height");
+         
+         if (!type)
+         {
+            type = type_from_filename(file);
+         }     
+         
+         if (!width || !height)
+         {
+            try 
+            {
+               std::auto_ptr<ImageReader> reader(get_image_reader(file));
+               if (reader.get())
+               {
+                  if (!width) width = reader->width();
+                  if (!height) height = reader->height();
+                  BOOST_ASSERT(*width > 0 && *height > 0);
+               }
+            }
+            catch (...)
+            {
+               std::cerr << "Exception caught while loading image:" << file << std::endl;
+            }   
+         }
          
          try
          {
@@ -817,7 +890,7 @@ namespace mapnik
             }
 #endif
 
-                polygon_pattern_symbolizer symbol(file,type,width,height);
+            polygon_pattern_symbolizer symbol(file,*type,*width,*height);
             rule.append(symbol);
          }
          catch (ImageReaderException const & ex )
@@ -1053,9 +1126,32 @@ namespace mapnik
 
          std::string image_file = get_attr<string>(sym, "file");
          optional<std::string> base = get_opt_attr<string>(sym, "base");
-            std::string type = get_attr<string>(sym, "type");
+         optional<std::string> type = get_opt_attr<string>(sym, "type");
-            unsigned width =  get_attr<unsigned>(sym, "width");
+         optional<unsigned> width =  get_opt_attr<unsigned>(sym, "width");
-            unsigned height =  get_attr<unsigned>(sym, "height");
+         optional<unsigned> height =  get_opt_attr<unsigned>(sym, "height");
+         
+         if (!type)
+         {
+            type = type_from_filename(image_file);
+         }     
+         
+         if (!width || !height)
+         {
+            try 
+            {
+               std::auto_ptr<ImageReader> reader(get_image_reader(image_file));
+               if (reader.get())
+               {
+                  if (!width) width = reader->width();
+                  if (!height) height = reader->height();
+                  BOOST_ASSERT(*width > 0 && *height > 0);
+               }
+            }
+            catch (...)
+            {
+               std::cerr << "Exception caught while loading image:" << image_file << std::endl;
+            }   
+         }
          
          try
          {   
@@ -1079,7 +1175,7 @@ namespace mapnik
 #endif
 
             shield_symbolizer shield_symbol(name,size,fill,
-                                                image_file,type,width,height);
+                                            image_file,*type,*width,*height);
             
             if (fontset_name && face_name)
             {