mapnik/tests/cpp_tests/geometry_converters_test.cpp

#include <boost/detail/lightweight_test.hpp>
#include <iostream>
#include <vector>
#include <algorithm>
#include "utils.hpp"

#include <mapnik/layer.hpp>
#include <mapnik/feature_type_style.hpp>
#include <mapnik/rule.hpp>
#include <mapnik/debug.hpp>
#include <mapnik/view_transform.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/vertex_converters.hpp>
#include <mapnik/geometry.hpp>
#include <mapnik/wkt/wkt_factory.hpp>
#include <mapnik/well_known_srs.hpp>
#include <mapnik/wkt/wkt_generator_grammar.hpp>
#include <mapnik/projection.hpp>
#include <mapnik/proj_transform.hpp>

// stl
#include <stdexcept>

struct output_geometry_backend
{
    output_geometry_backend(mapnik::geometry_container & paths, mapnik::geometry_type::types type)
        : paths_(paths),
          type_(type) {}

    template <typename T>
    void add_path(T & path)
    {
        mapnik::vertex2d vtx(mapnik::vertex2d::no_init);
        path.rewind(0);
        std::unique_ptr<mapnik::geometry_type> geom_ptr(new mapnik::geometry_type(type_));

        while ((vtx.cmd = path.vertex(&vtx.x, &vtx.y)) != mapnik::SEG_END)
        {
            //std::cerr << vtx.x << "," << vtx.y << "   cmd=" << vtx.cmd << std::endl;
            geom_ptr->push_vertex(vtx.x, vtx.y, (mapnik::CommandType)vtx.cmd);
        }
        paths_.push_back(geom_ptr.release());
    }
    mapnik::geometry_container &  paths_;
    mapnik::geometry_type::types type_;
};

boost::optional<std::string> linestring_bbox_clipping(mapnik::box2d<double> bbox,
                                                      std::string wkt_in)
{
    using namespace mapnik;
    agg::trans_affine tr;
    projection src(MAPNIK_LONGLAT_PROJ);
    projection dst(MAPNIK_LONGLAT_PROJ);
    proj_transform prj_trans(src,dst);
    line_symbolizer sym;
    view_transform t(bbox.width(),bbox.height(), bbox);
    mapnik::geometry_container output_paths;
    output_geometry_backend backend(output_paths, mapnik::geometry_type::types::LineString);

    mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
    mapnik::feature_impl f(ctx,0);
    vertex_converter<output_geometry_backend,clip_line_tag>
        converter(bbox, backend, sym, t, prj_trans, tr, f, attributes(), 1.0);

    converter.set<clip_line_tag>();

    mapnik::geometry_container p;
    if (!mapnik::from_wkt(wkt_in , p))
    {
        throw std::runtime_error("Failed to parse WKT");
    }

    for (geometry_type const& geom : p)
    {
        vertex_adapter va(geom);
        converter.apply(va);
    }

    using sink_type = std::back_insert_iterator<std::string>;
    std::string wkt;
    sink_type sink(wkt);
    static const mapnik::wkt::wkt_multi_generator<sink_type, mapnik::geometry_container> generator;
    if (boost::spirit::karma::generate(sink, generator, output_paths))
    {
        return boost::optional<std::string>(wkt);
    }
    return boost::optional<std::string>();
}

boost::optional<std::string> polygon_bbox_clipping(mapnik::box2d<double> bbox,
                                                   std::string wkt_in)
{
    using namespace mapnik;
    agg::trans_affine tr;
    projection src(MAPNIK_LONGLAT_PROJ);
    projection dst(MAPNIK_LONGLAT_PROJ);
    proj_transform prj_trans(src,dst);
    polygon_symbolizer sym;
    view_transform t(bbox.width(),bbox.height(), bbox);
    mapnik::geometry_container output_paths;
    output_geometry_backend backend(output_paths, mapnik::geometry_type::types::Polygon);

    mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
    mapnik::feature_impl f(ctx,0);
    vertex_converter<output_geometry_backend, clip_poly_tag>
        converter(bbox, backend, sym, t, prj_trans, tr, f, attributes(), 1.0);

    converter.set<clip_poly_tag>();

    mapnik::geometry_container p;
    if (!mapnik::from_wkt(wkt_in , p))
    {
        throw std::runtime_error("Failed to parse WKT");
    }

    for (geometry_type const& geom : p)
    {
        vertex_adapter va(geom);
        converter.apply(va);
    }

    using sink_type = std::back_insert_iterator<std::string>;
    std::string wkt; // Use Python String directly ?
    sink_type sink(wkt);
    static const mapnik::wkt::wkt_multi_generator<sink_type, mapnik::geometry_container> generator;
    if (boost::spirit::karma::generate(sink, generator, output_paths))
    {
        return boost::optional<std::string>(wkt);
    }

    return boost::optional<std::string>();
}

int main(int argc, char** argv)
{
    std::vector<std::string> args;
    for (int i=1;i<argc;++i)
    {
        args.push_back(argv[i]);
    }
    bool quiet = std::find(args.begin(), args.end(), "-q")!=args.end();

    BOOST_TEST(set_working_dir(args));

    try
    {
        // LineString/bbox clipping
        {
            std::string wkt_in("LineString(0 0,200 200)");
            boost::optional<std::string> result = linestring_bbox_clipping(mapnik::box2d<double>(50,50,150,150),wkt_in);
            BOOST_TEST(result);
            BOOST_TEST_EQ(*result,std::string("LineString(50 50,150 150)"));
        }
        // Polygon/bbox clipping
        {
            std::string wkt_in("Polygon((50 50,150 50,150 150,50 150,50 50))");
            boost::optional<std::string> result = polygon_bbox_clipping(mapnik::box2d<double>(50,50,150,150),wkt_in);
            BOOST_TEST(result);
            // TODO - the extra 50 50 is not ideal, but we enforce this result for now to prevent
            // regressions and because we don't have actionable solution to drop extra 50 50
            BOOST_TEST_EQ(*result,std::string("Polygon((50 50,150 50,150 150,50 150,50 50,50 50))"));
            // below is ideal, but not current result
            //BOOST_TEST_EQ(*result,std::string("Polygon((50 50,150 50,150 150,50 150,50 50))"));
        }
        
        {
            std::string wkt_in("Polygon((60 60,140 60,140 160,60 140,60 60))");
            boost::optional<std::string> result = polygon_bbox_clipping(mapnik::box2d<double>(50,50,150,150),wkt_in);
            BOOST_TEST(result);
            BOOST_TEST_EQ(*result,std::string("Polygon((60 60,140 60,140 150,100 150,60 140,60 60,60 60))"));
            //BOOST_TEST_EQ(*result,std::string("Polygon((60 60,140 60,140 160,60 140,60 60))"));
        }

        {
            std::string wkt_in("Polygon((0 0,10 0,10 10,0 10,0 0))");
            boost::optional<std::string> result = polygon_bbox_clipping(mapnik::box2d<double>(50,50,150,150),wkt_in);
            BOOST_TEST(result);
            // TODO - this is completely wrong: should not have )) and ideally should be EMPTY
            BOOST_TEST_EQ(*result, std::string("Polygon())"));
        }
        {
            std::string wkt_in("Polygon((0 0,100 200,200 0,0 0 ))");
            boost::optional<std::string> result = polygon_bbox_clipping(mapnik::box2d<double>(50,50,150,150),wkt_in);
            BOOST_TEST(result);
            BOOST_TEST_EQ(*result,  std::string("Polygon((50 50,50 100,75 150,125 150,150 100,150 50))"));
            //BOOST_TEST_EQ(*result,std::string("Polygon((50 50,50 100,75 150,125 150,150 100,150 50,50 50))"));
        }
        
    }
    catch (std::exception const & ex)
    {
        std::clog << ex.what() << "\n";
        BOOST_TEST(false);
    }


    if (!::boost::detail::test_errors())
    {
        if (quiet) std::clog << "\x1b[1;32m.\x1b[0m";
        else std::clog << "C++ geometry conversions: \x1b[1;32m✓ \x1b[0m\n";
        ::boost::detail::report_errors_remind().called_report_errors_function = true;
    }
    else
    {
        return ::boost::report_errors();
    }
}