+ symbolizers: add hash impl

bindings/python/mapnik_line_symbolizer.cpp

@@ -23,12 +23,19 @@
 #include <boost/python.hpp>
 #include "mapnik_enumeration.hpp"
 #include <mapnik/line_symbolizer.hpp>
+#include <mapnik/symbolizer_hash.hpp>
 
 using namespace mapnik;
 using mapnik::line_symbolizer;
 using mapnik::stroke;
 using mapnik::color;
 
+std::size_t line_symbolizer_hash(line_symbolizer const& sym)
+{
+    return symbolizer_hash::value(sym);
+}
+
+
 void export_line_symbolizer()
 {
     using namespace boost::python;
@@ -68,5 +75,6 @@ void export_line_symbolizer()
                       &line_symbolizer::smooth,
                       &line_symbolizer::set_smooth,
                       "smooth value (0..1.0)")
+        .def("__hash__", line_symbolizer_hash)
         ;
 }

bindings/python/mapnik_polygon_symbolizer.cpp

@@ -22,11 +22,17 @@
 
 #include <boost/python.hpp>
 #include <mapnik/polygon_symbolizer.hpp>
+#include <mapnik/symbolizer_hash.hpp>
 
 using namespace mapnik;
 using mapnik::polygon_symbolizer;
 using mapnik::color;
 
+std::size_t polygon_symbolizer_hash(polygon_symbolizer const& sym)
+{
+    return symbolizer_hash::value(sym);
+}
+
 void export_polygon_symbolizer()
 {
     using namespace boost::python;
@@ -64,6 +70,7 @@ void export_polygon_symbolizer()
                       &polygon_symbolizer::simplify_tolerance,
                       &polygon_symbolizer::set_simplify_tolerance,
                       "simplfication tolerance measure")
+        .def("__hash__", polygon_symbolizer_hash)
         ;
 
 }

bindings/python/mapnik_symbolizer.cpp

@@ -27,6 +27,7 @@
 // mapnik
 //symbolizer typdef here rather than mapnik/symbolizer.hpp
 #include <mapnik/rule.hpp>
+#include <mapnik/symbolizer_hash.hpp>
 
 using mapnik::symbolizer;
 
@@ -169,6 +170,20 @@ const markers_symbolizer& markers_( const symbolizer& symbol )
     return boost::get<markers_symbolizer>(symbol);
 }
 
+struct symbolizer_hash_visitor : public boost::static_visitor<std::size_t>
+{
+    template <typename T>
+    std::size_t operator() (T const& sym) const
+    {
+        return mapnik::symbolizer_hash::value(sym);
+    }
+};
+
+std::size_t hash_impl(symbolizer const& sym)
+{
+    return boost::apply_visitor(symbolizer_hash_visitor(), sym);
+}
+
 void export_symbolizer()
 {
     using namespace boost::python;
@@ -177,6 +192,8 @@ void export_symbolizer()
 
         .def("type",get_symbol_type)
 
+        .def("__hash__",hash_impl)
+
         .def("point",point_,
              return_value_policy<copy_const_reference>())
 

include/mapnik/symbolizer_hash.hpp

@@ -0,0 +1,66 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2013 Artem Pavlenko
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *****************************************************************************/
+
+#ifndef MAPNIK_SYMBOLIZER_HASH_HPP
+#define MAPNIK_SYMBOLIZER_HASH_HPP
+
+#include <mapnik/map.hpp>
+#include <mapnik/feature_type_style.hpp>
+
+#include <boost/functional/hash.hpp>
+#include <boost/variant/static_visitor.hpp>
+
+namespace mapnik {
+
+struct symbolizer_hash
+{
+    template <typename T>
+    static std::size_t value(T const& sym)
+    {
+        std::size_t seed = 0;
+        return seed;
+    }
+    // specialisation for polygon_symbolizer
+    static std::size_t value(polygon_symbolizer const& sym)
+    {
+        std::size_t seed = Polygon;
+        boost::hash_combine(seed, sym.get_fill().rgba());
+        boost::hash_combine(seed, sym.get_opacity());
+        return seed;
+    }
+
+    // specialisation for line_symbolizer
+    static std::size_t value(line_symbolizer const& sym)
+    {
+        std::size_t seed = LineString;
+        boost::hash_combine(seed, sym.get_stroke().get_color().rgba());
+        boost::hash_combine(seed, sym.get_stroke().get_width());
+        boost::hash_combine(seed, sym.get_stroke().get_opacity());
+        boost::hash_combine(seed, static_cast<int>(sym.get_stroke().get_line_cap()));
+        boost::hash_combine(seed, static_cast<int>(sym.get_stroke().get_line_join()));
+        return seed;
+    }
+};
+
+}
+
+#endif // MAPNIK_SYMBOLIZER_HASH_HPP