mapnik/plugins/input/gdal/gdal_featureset.hpp
2024-07-22 10:20:47 +01:00

94 lines
3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2024 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
*
*****************************************************************************/
#ifndef GDAL_FEATURESET_HPP
#define GDAL_FEATURESET_HPP
// mapnik
#include <mapnik/feature.hpp>
#include <mapnik/featureset.hpp>
#include <mapnik/query.hpp>
#include <mapnik/util/variant.hpp>
#include <optional>
class GDALDataset;
class GDALRasterBand;
using gdal_query = mapnik::util::variant<mapnik::query, mapnik::coord2d>;
class gdal_featureset : public mapnik::Featureset
{
struct query_dispatch
{
query_dispatch(gdal_featureset& featureset)
: featureset_(featureset)
{}
mapnik::feature_ptr operator()(mapnik::query const& q) const { return featureset_.get_feature(q); }
mapnik::feature_ptr operator()(mapnik::coord2d const& p) const { return featureset_.get_feature_at_point(p); }
gdal_featureset& featureset_;
};
public:
gdal_featureset(GDALDataset& dataset,
int band,
gdal_query q,
mapnik::box2d<double> extent,
unsigned width,
unsigned height,
int nbands,
double dx,
double dy,
std::optional<double> const& nodata,
double nodata_tolerance,
int64_t max_image_area);
virtual ~gdal_featureset();
mapnik::feature_ptr next();
private:
void find_best_overview(int bandNumber,
int ideal_width,
int ideal_height,
int& current_width,
int& current_height) const;
mapnik::feature_ptr get_feature(mapnik::query const& q);
mapnik::feature_ptr get_feature_at_point(mapnik::coord2d const& p);
GDALDataset& dataset_;
mapnik::context_ptr ctx_;
int band_;
gdal_query gquery_;
mapnik::box2d<double> raster_extent_;
unsigned raster_width_;
unsigned raster_height_;
double dx_;
double dy_;
int nbands_;
std::optional<double> nodata_value_;
double nodata_tolerance_;
int64_t max_image_area_;
bool first_;
};
#endif // GDAL_FEATURESET_HPP