mapnik/plugins/input/templates/helloworld/hello_datasource.hpp

51 lines
1.5 KiB
C++

#ifndef FILE_DATASOURCE_HPP
#define FILE_DATASOURCE_HPP
// mapnik
#include <mapnik/datasource.hpp>
class hello_datasource : public mapnik::datasource
{
public:
// constructor
// arguments must not change
hello_datasource(mapnik::parameters const& params, bool bind=true);
// destructor
virtual ~hello_datasource ();
// mandatory: type of the plugin, used to match at runtime
int type() const;
// mandatory: name of the plugin
static std::string name();
// mandatory: function to query features by box2d
// this is called when rendering, specifically in feature_style_processor.hpp
mapnik::featureset_ptr features(mapnik::query const& q) const;
// mandatory: function to query features by point (coord2d)
// not used by rendering, but available to calling applications
mapnik::featureset_ptr features_at_point(mapnik::coord2d const& pt) const;
// mandatory: return the box2d of the datasource
// called during rendering to determine if the layer should be processed
mapnik::box2d<double> envelope() const;
// mandatory: return the layer descriptor
mapnik::layer_descriptor get_descriptor() const;
// mandatory: will bind the datasource given params
void bind() const;
private:
// recommended naming convention of datasource members:
// name_, type_, extent_, and desc_
static const std::string name_;
int type_;
mutable mapnik::layer_descriptor desc_;
mutable mapnik::box2d<double> extent_;
};
#endif // FILE_DATASOURCE_HPP