mapnik/plugins/input/templates/helloworld/hello_featureset.cpp

68 lines
2 KiB
C++

// mapnik
#include <mapnik/feature_factory.hpp>
#include <mapnik/value_types.hpp>
// boost
#include "hello_featureset.hpp"
hello_featureset::hello_featureset(mapnik::box2d<double> const& box, std::string const& encoding)
: box_(box),
feature_id_(1),
tr_(new mapnik::transcoder(encoding)),
ctx_(std::make_shared<mapnik::context_type>()) {
// add known field names to attributes schema
ctx_->push("key");
}
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(ctx_,feature_id_));
// increment the count
++feature_id_;
// create an attribute pair of key:value
feature->put("key",tr_->transcode("hello world point!"));
// take the center of the bbox that was used to query
// to dynamically generate a fake point
mapnik::coord2d center = box_.center();
// create a new point geometry
feature->set_geometry(mapnik::new_geometry::point(center.x,center.y));
// return the feature!
return feature;
}
else if (feature_id_ == 2)
{
// create a second feature
mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx_,feature_id_));
// increment the count
++feature_id_;
// create an attribute pair of key:value
feature->put("key",tr_->transcode("hello world line!"));
// take the outer ring of the bbox that was used to query
// to dynamically generate a fake line
mapnik::new_geometry::line_string line;
line.reserve(4);
line.add_coord(box_.minx(),box_.maxy());
line.add_coord(box_.maxx(),box_.maxy());
line.add_coord(box_.maxx(),box_.miny());
line.add_coord(box_.minx(),box_.miny());
feature->set_geometry(std::move(line));
return feature;
}
// otherwise return an empty feature
return mapnik::feature_ptr();
}