mapnik/include/mapnik/filter.hpp
Artem Pavlenko d959701d5a 1. added boost::optional<T> to/form Python converter
2. make background color optional (Map object)
3. exposed 'blend' method for Image object
2007-08-01 09:59:23 +00:00

90 lines
2.5 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2006 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
*
*****************************************************************************/
//$Id$
#ifndef FILTER_HPP
#define FILTER_HPP
#include <mapnik/config.hpp>
#include <mapnik/feature.hpp>
namespace mapnik
{
template <typename FeatureT> class filter_visitor;
template <typename FeatureT>
class MAPNIK_DECL filter
{
public:
virtual bool pass(const FeatureT& feature) const=0;
virtual filter<FeatureT>* clone() const=0;
virtual void accept(filter_visitor<FeatureT>& v) = 0;
virtual std::string to_string() const=0;
virtual ~filter() {}
};
typedef boost::shared_ptr<filter<Feature> > filter_ptr;
template <typename FeatureT>
class all_filter : public filter<FeatureT>
{
public:
bool pass (const FeatureT&) const
{
return true;
}
filter<FeatureT>* clone() const
{
return new all_filter<FeatureT>;
}
std::string to_string() const
{
return "true";
}
void accept(filter_visitor<FeatureT>&) {}
virtual ~all_filter() {}
};
template <typename FeatureT>
class none_filter : public filter<FeatureT>
{
public:
bool pass (const FeatureT&) const
{
return false;
}
filter<FeatureT>* clone() const
{
return new none_filter<FeatureT>;
}
std::string to_string() const
{
return "false";
}
void accept(filter_visitor<FeatureT>&) {}
virtual ~none_filter() {}
};
}
#endif //FILTER_HPP