mapnik/src/svg/output/process_symbolizers.cpp
2015-06-15 20:41:48 -07:00

153 lines
5.7 KiB
C++

/*****************************************************************************
*
* 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
*
*****************************************************************************/
#if defined(SVG_RENDERER)
// mapnik
#include <mapnik/symbolizer.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/transform_path_adapter.hpp>
#include <mapnik/svg/output/svg_renderer.hpp>
#include <mapnik/svg/geometry_svg_generator_impl.hpp>
#include <mapnik/svg/output/svg_output_grammars.hpp>
#include <mapnik/svg/output/svg_output_attributes.hpp>
#include <mapnik/symbolizer_dispatch.hpp>
#include <mapnik/vertex_processor.hpp>
#include <mapnik/geometry_transform.hpp>
#include <mapnik/geometry_to_path.hpp>
#include <mapnik/util/geometry_to_ds_type.hpp>
#include <mapnik/safe_cast.hpp>
// boost
#include <boost/spirit/include/karma.hpp>
namespace mapnik { namespace geometry {
template <typename CalculationType>
struct coord_transformer
{
using calc_type = CalculationType;
coord_transformer(view_transform const& tr, proj_transform const& prj_trans)
: tr_(tr), prj_trans_(prj_trans) {}
template <typename P1, typename P2>
inline bool apply(P1 const& p1, P2 & p2) const
{
using coordinate_type = typename boost::geometry::coordinate_type<P2>::type;
calc_type x = boost::geometry::get<0>(p1);
calc_type y = boost::geometry::get<1>(p1);
calc_type z = 0.0;
if (!prj_trans_.backward(x, y, z)) return false;
tr_.forward(&x,&y);
boost::geometry::set<0>(p2, safe_cast<coordinate_type>(x));
boost::geometry::set<1>(p2, safe_cast<coordinate_type>(y));
return true;
}
view_transform const& tr_;
proj_transform const& prj_trans_;
};
} // ns geometry
struct symbol_type_dispatch
{
template <typename Symbolizer>
bool operator()(Symbolizer const&) const
{
return false;
}
bool operator()(line_symbolizer const&) const
{
return true;
}
bool operator()(polygon_symbolizer const&) const
{
return true;
}
};
bool is_path_based(symbolizer const& sym)
{
return util::apply_visitor(symbol_type_dispatch(), sym);
}
template <typename OutputIterator, typename PathType>
void generate_path_impl(OutputIterator & output_iterator, PathType const& path, svg::path_output_attributes const& path_attributes)
{
using path_dash_array_grammar = svg::svg_path_dash_array_grammar<OutputIterator>;
using path_attributes_grammar = svg::svg_path_attributes_grammar<OutputIterator>;
static const path_attributes_grammar attributes_grammar;
static const path_dash_array_grammar dash_array_grammar;
static const svg::svg_path_generator<OutputIterator,PathType> svg_path_grammer;
boost::spirit::karma::lit_type lit;
boost::spirit::karma::generate(output_iterator, lit("<path ") << svg_path_grammer, path);
boost::spirit::karma::generate(output_iterator, lit(" ") << dash_array_grammar, path_attributes.stroke_dasharray());
boost::spirit::karma::generate(output_iterator, lit(" ") << attributes_grammar << lit("/>\n"), path_attributes);
}
template <typename OutputIterator>
bool svg_renderer<OutputIterator>::process(rule::symbolizers const& syms,
mapnik::feature_impl & feature,
proj_transform const& prj_trans)
{
// svg renderer supports processing of multiple symbolizers.
using trans_path_type = transform_path_adapter<view_transform, vertex_adapter>;
bool process_path = false;
// process each symbolizer to collect its (path) information.
// path information (attributes from line_ and polygon_ symbolizers)
// is collected with the path_attributes_ data member.
for (auto const& sym : syms)
{
if (is_path_based(sym))
{
process_path = true;
}
util::apply_visitor(symbolizer_dispatch<svg_renderer<OutputIterator>>(*this, feature, prj_trans), sym);
}
if (process_path)
{
// generate path output for each geometry of the current feature.
auto const& geom = feature.get_geometry();
path_type path;
path.set_type(static_cast<path_type::types>(mapnik::util::to_ds_type(geom)));
geometry::to_path(geom, path);
vertex_adapter va(path);
trans_path_type trans_path(common_.t_, va, prj_trans);
generate_path_impl(generator_.output_iterator_, trans_path, path_attributes_);
// set the previously collected values back to their defaults
// for the feature that will be processed next.
path_attributes_.reset();
}
return true;
}
template bool svg_renderer<std::ostream_iterator<char> >::process(rule::symbolizers const& syms,
mapnik::feature_impl & feature,
proj_transform const& prj_trans);
}
#endif