// mapnik #include #include #include "hello_featureset.hpp" hello_featureset::hello_featureset(mapnik::box2d const& box, std::string const& encoding) : box_(box), feature_id_(1), tr_(new mapnik::transcoder(encoding)) { } hello_featureset::~hello_featureset() { } mapnik::feature_ptr hello_featureset::next() { if (feature_id_ == 1) { // create a new feature mapnik::feature_ptr feature(mapnik::feature_factory::create(feature_id_)); // increment the count so that we only return one feature ++feature_id_; // create an attribute pair of key:value UnicodeString ustr = tr_->transcode("hello world!"); boost::put(*feature,"key",ustr); // we need a geometry to display so just for fun here // we take the center of the bbox that was used to query // since we don't actually have any data to pull from... mapnik::coord2d center = box_.center(); // create a new point geometry mapnik::geometry_type * pt = new mapnik::geometry_type(mapnik::Point); // we use path type geometries in Mapnik to fit nicely with AGG and Cairo // here we stick an x,y pair into the geometry using move_to() pt->move_to(center.x,center.y); // add the geometry to the feature feature->add_geometry(pt); // A feature usually will have just one geometry of a given type // but mapnik does support many geometries per feature of any type // so here we draw a line around the point mapnik::geometry_type * line = new mapnik::geometry_type(mapnik::LineString); line->move_to(box_.minx(),box_.miny()); line->line_to(box_.minx(),box_.maxy()); line->line_to(box_.maxx(),box_.maxy()); line->line_to(box_.maxx(),box_.miny()); line->line_to(box_.minx(),box_.miny()); feature->add_geometry(line); // return the feature! return feature; } // otherwise return an empty feature return mapnik::feature_ptr(); }