mapnik/include/mapnik/proj_transform.hpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2014 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_PROJ_TRANSFORM_HPP
#define MAPNIK_PROJ_TRANSFORM_HPP

// mapnik
#include <mapnik/config.hpp>
#include <mapnik/util/noncopyable.hpp>
#include <mapnik/geometry_adapters.hpp>

namespace mapnik {

namespace geometry {
template <typename T> struct point;
template <typename T> struct line_string;
}
class projection;
template <typename T> class box2d;

class MAPNIK_DECL proj_transform : private util::noncopyable
{
public:
    proj_transform(projection const& source,
                   projection const& dest);

    bool equal() const;
    bool is_known() const;
    bool forward (double& x, double& y , double& z) const;
    bool backward (double& x, double& y , double& z) const;
    bool forward (double *x, double *y , double *z, int point_count, int offset = 1) const;
    bool backward (double *x, double *y , double *z, int point_count, int offset = 1) const;
    bool forward (geometry::point<double> & p) const;
    bool backward (geometry::point<double> & p) const;
    unsigned int forward (geometry::line_string<double> & ls) const;
    unsigned int backward (geometry::line_string<double> & ls) const;
    bool forward (box2d<double> & box) const;
    bool backward (box2d<double> & box) const;
    bool forward (box2d<double> & box, int points) const;
    bool backward (box2d<double> & box, int points) const;
    mapnik::projection const& source() const;
    mapnik::projection const& dest() const;

private:
    projection const& source_;
    projection const& dest_;
    bool is_source_longlat_;
    bool is_dest_longlat_;
    bool is_source_equal_dest_;
    bool wgs84_to_merc_;
    bool merc_to_wgs84_;
};

struct proj_strategy
{
    proj_strategy(proj_transform const& prj_trans)
        : prj_trans_(prj_trans) {}

    template <typename P1, typename P2>
    inline bool apply(P1 const& p1, P2 & p2) const
    {
        using p2_type = typename boost::geometry::coordinate_type<P2>::type;
        double x = boost::geometry::get<0>(p1);
        double y = boost::geometry::get<1>(p1);
        double z = 0.0;
        if (!prj_trans_.forward(x, y, z)) return false;
        try {
            boost::geometry::set<0>(p2, boost::numeric_cast<p2_type>(x));
        }
        catch(boost::numeric::negative_overflow&)
        {
            boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::min());
        }
        catch(boost::numeric::positive_overflow&) 
        {
            boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::max());
        }
        try {
            boost::geometry::set<1>(p2, boost::numeric_cast<p2_type>(y));
        }
        catch(boost::numeric::negative_overflow&)
        {
            boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::min());
        }
        catch(boost::numeric::positive_overflow&) 
        {
            boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::max());
        }
        return true;
    }
    
    template <typename P1, typename P2>
    inline P2 execute(P1 const& p1, bool & status) const
    {
        P2 p2;
        status = apply(p1, p2);
        return p2;
    }

    proj_transform const& prj_trans_;
};

struct proj_backward_strategy
{
    proj_backward_strategy(proj_transform const& prj_trans)
        : prj_trans_(prj_trans) {}

    template <typename P1, typename P2>
    inline bool apply(P1 const& p1, P2 & p2) const
    {
        using p2_type = typename boost::geometry::coordinate_type<P2>::type;
        double x = boost::geometry::get<0>(p1);
        double y = boost::geometry::get<1>(p1);
        double z = 0.0;
        if (!prj_trans_.backward(x, y, z)) return false;
        try {
            boost::geometry::set<0>(p2, boost::numeric_cast<p2_type>(x));
        }
        catch(boost::numeric::negative_overflow&)
        {
            boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::min());
        }
        catch(boost::numeric::positive_overflow&) 
        {
            boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::max());
        }
        try {
            boost::geometry::set<1>(p2, boost::numeric_cast<p2_type>(y));
        }
        catch(boost::numeric::negative_overflow&)
        {
            boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::min());
        }
        catch(boost::numeric::positive_overflow&) 
        {
            boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::max());
        }
        return true;
    }
    
    template <typename P1, typename P2>
    inline P2 execute(P1 const& p1, bool & status) const
    {
        P2 p2;
        status = apply(p1, p2);
        return p2;
    }

    proj_transform const& prj_trans_;
};

}

#endif // MAPNIK_PROJ_TRANSFORM_HPP