mapnik/include/attribute_collector.hpp
Artem Pavlenko af2601eea0 1. new style/feature processor abstraction allowing plugable backends.
(to construct custom 'Output' derive from feature_style_processor (CRTP) e.g
	class MyOutput : public feature_style_processor<MyOutput>
     and implement:
	 process(***_symbolizer const&, Feature const&)
     methods
   At the moment only AGG renderer is implemented
2006-02-07 14:41:41 +00:00

62 lines
1.6 KiB
C++

/* This file is part of Mapnik (c++ mapping toolkit)
* Copyright (C) 2005 Artem Pavlenko
*
* Mapnik is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
//$Id$
#ifndef ATTRIBUTE_COLLECTOR_HPP
#define ATTRIBUTE_COLLECTOR_HPP
#include "filter.hpp"
#include "expression.hpp"
#include "feature_layer_desc.hpp"
#include <set>
namespace mapnik
{
template <typename FeatureT>
class attribute_collector : public filter_visitor<FeatureT>
{
public:
attribute_collector(std::set<std::string>& names)
: names_(names) {}
void visit(filter<FeatureT>& /*filter*/)
{
//not interested
}
void visit(expression<FeatureT>& exp)
{
property<FeatureT>* pf;
if ((pf = dynamic_cast<property<FeatureT>*>(&exp)))
{
names_.insert(pf->name());
}
}
virtual ~attribute_collector() {}
private:
// no copying
attribute_collector(attribute_collector const&);
attribute_collector& operator=(attribute_collector const&);
private:
std::set<std::string>& names_;
};
}
#endif //ATTRIBUTE_COLLECTOR_HPP