mapnik/include/mapnik/svg/geometry_svg_generator.hpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2017 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_GEOMETRY_SVG_PATH_GENERATOR_HPP
#define MAPNIK_GEOMETRY_SVG_PATH_GENERATOR_HPP


// mapnik
#include <mapnik/global.hpp>
// for container stuff
#include <mapnik/geometry.hpp>
#include <mapnik/view_transform.hpp> // for container stuff
#include <mapnik/transform_path_adapter.hpp>
#include <mapnik/util/path_iterator.hpp>
#include <mapnik/util/container_adapter.hpp>

#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/spirit/include/karma.hpp>
#include <boost/spirit/include/phoenix_function.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <boost/fusion/adapted/std_tuple.hpp>
#include <boost/type_traits/remove_pointer.hpp>
#pragma GCC diagnostic pop

#include <tuple>

// adapted to conform to the concepts
// required by Karma to be recognized as a container of
// attributes for output generation.

namespace boost { namespace spirit { namespace traits {

// TODO - this needs to be made generic to any path type
using path_type = mapnik::transform_path_adapter<mapnik::view_transform, mapnik::vertex_adapter>;

template <>
struct is_container<path_type const> : mpl::true_ {} ;

template <>
struct container_iterator<path_type const>
{
    using type = mapnik::util::path_iterator<path_type>;
};

template <>
struct begin_container<path_type const>
{
    static mapnik::util::path_iterator<path_type>
    call (path_type const& g)
    {
        return mapnik::util::path_iterator<path_type>(g);
    }
};

template <>
struct end_container<path_type const>
{
    static mapnik::util::path_iterator<path_type>
    call (path_type const& /*g*/)
    {
        return mapnik::util::path_iterator<path_type>();
    }
};

}}}


namespace mapnik { namespace svg {

namespace karma = boost::spirit::karma;
namespace phoenix = boost::phoenix;

namespace svg_detail {

template <typename Geometry>
struct get_type
{
    using result_type = int;
    result_type operator() (Geometry const& geom) const
    {
        return static_cast<int>(geom.type());
    }
};

template <typename T>
struct get_first
{
    using path_type = T;
    using result_type = typename path_type::value_type const;
    result_type operator() (path_type const& geom) const
    {
        typename path_type::value_type coord;
        geom.rewind(0);
        std::get<0>(coord) = geom.vertex(&std::get<1>(coord),&std::get<2>(coord));
        return coord;
    }
};

template <>
struct get_first<mapnik::path_type>
{
    using path_type = mapnik::path_type;
    using result_type = path_type::value_type const;
    result_type operator() (path_type const& geom) const
    {
        path_type::value_type coord;
        std::get<0>(coord) = geom.cont_.get_vertex(0, &std::get<1>(coord),&std::get<2>(coord));
        return coord;
    }
};


template <typename T>
struct coordinate_policy : karma::real_policies<T>
{
    using base_type = boost::spirit::karma::real_policies<T>;
    static int floatfield(T) { return base_type::fmtflags::fixed; }
    static unsigned precision(T) { return 4u ;}
};
}

template <typename OutputIterator, typename Path>
struct svg_path_generator :
        karma::grammar<OutputIterator, Path const& ()>
{

    using path_type = Path;
    using coordinate_type = typename boost::remove_pointer<typename path_type::value_type>::type;

    svg_path_generator();
    // rules
    karma::rule<OutputIterator, path_type const& ()> svg;
    karma::rule<OutputIterator, path_type const& ()> point;
    karma::rule<OutputIterator, path_type const& ()> linestring;
    karma::rule<OutputIterator, path_type const& ()> polygon;
    karma::rule<OutputIterator, coordinate_type ()> svg_point;
    karma::rule<OutputIterator, path_type const& ()> svg_path;

    // phoenix functions
    phoenix::function<svg_detail::get_type<path_type> > _type;
    phoenix::function<svg_detail::get_first<path_type> > _first;
    //
    karma::real_generator<double, svg_detail::coordinate_policy<double> > coordinate;

};

}}

#endif // MAPNIK_GEOMETRY_SVG_PATH_GENERATOR_HPP