mapnik/src/proj_transform.cpp

/*****************************************************************************
 * 
 * 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
 *
 *****************************************************************************/

//$Id$

// mapnik
#include <mapnik/proj_transform.hpp>
#include <mapnik/utils.hpp>
// proj4
#include <proj_api.h>

namespace mapnik {
    
proj_transform::proj_transform(projection const& source, 
                               projection const& dest)
    : source_(source),
      dest_(dest) 
{
    is_source_longlat_ = source_.is_geographic();
    is_dest_longlat_ = dest_.is_geographic();
    is_source_equal_dest_ = (source_ == dest_);
}

bool proj_transform::equal() const
{
    return is_source_equal_dest_;
}

bool proj_transform::forward (double & x, double & y , double & z) const
{
    if (is_source_equal_dest_)
        return true;

    if (is_source_longlat_)
    {
        x *= DEG_TO_RAD;
        y *= DEG_TO_RAD;
    }

#if defined(MAPNIK_THREADSAFE) && PJ_VERSION < 480
    mutex::scoped_lock lock(projection::mutex_);
#endif
        
    if (pj_transform( source_.proj_, dest_.proj_, 1, 
                      0, &x,&y,&z) != 0)
    {
        return false;
    }
        
    if (is_dest_longlat_)
    {
        x *= RAD_TO_DEG;
        y *= RAD_TO_DEG;
    }
        
    return true;
} 
        
bool proj_transform::backward (double & x, double & y , double & z) const
{
    if (is_source_equal_dest_)
        return true;
      
    if (is_dest_longlat_)
    {
        x *= DEG_TO_RAD;
        y *= DEG_TO_RAD;
    }
        
#if defined(MAPNIK_THREADSAFE) && PJ_VERSION < 480
    mutex::scoped_lock lock(projection::mutex_);
#endif

    if (pj_transform( dest_.proj_, source_.proj_, 1, 
                      0, &x,&y,&z) != 0)
    {
        return false;
    }
        
    if (is_source_longlat_)
    {
        x *= RAD_TO_DEG;
        y *= RAD_TO_DEG;
    }
        
    return true;
}

bool proj_transform::forward (box2d<double> & box) const
{
    if (is_source_equal_dest_)
        return true;
    double minx = box.minx();
    double miny = box.miny();
    double maxx = box.maxx();
    double maxy = box.maxy();
    double z = 0.0;
    if (!forward(minx,miny,z))
        return false;
    if (!forward(maxx,maxy,z))
        return false;
    box.init(minx,miny,maxx,maxy);
    return true;
} 
        
bool proj_transform::backward (box2d<double> & box) const
{
    if (is_source_equal_dest_)
        return true;

    double minx = box.minx();
    double miny = box.miny();
    double maxx = box.maxx();
    double maxy = box.maxy();
    double z = 0.0;
    if (!backward(minx,miny,z))
        return false;
    if (!backward(maxx,maxy,z))
        return false;
    box.init(minx,miny,maxx,maxy);
    return true;
}

mapnik::projection const& proj_transform::source() const
{
    return source_;
}
mapnik::projection const& proj_transform::dest() const
{
    return dest_;
}
 
}