mapnik/plugins/input/pgraster/pgraster_wkb_reader.hpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2021 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
 *
 *****************************************************************************
 *
 * Initially developed by Sandro Santilli <strk@keybit.net> for CartoDB
 *
 *****************************************************************************/

#ifndef PGRASTER_WKB_READER_HPP
#define PGRASTER_WKB_READER_HPP

// mapnik
#include <mapnik/feature.hpp> // for raster_ptr
#include <mapnik/geometry/box2d.hpp>

enum pgraster_color_interp {
    // Automatic color interpretation:
    // uses grayscale for single band, rgb for 3 bands
    // rgba for 4 bands
    pgr_auto,
    // Grayscale interpretation
    pgr_grayscale,
    pgr_indexed,
    pgr_rgb,
    pgr_rgba
};

class pgraster_wkb_reader
{
  public:

    pgraster_wkb_reader(const uint8_t* wkb, int size, int bnd = 0)
        : ptr_(wkb)
        , bandno_(bnd)
    {}

    mapnik::raster_ptr get_raster();

    /// @param bnd band number. If 0 (default) it'll try to read all bands
    ///            with automatic color interpretation (rgb for 3 bands,
    ///            rgba for 4 bands, grayscale for 1 band).
    ///            Any other value results in pixel
    ///            values being copied verbatim into the returned raster
    ///            for interpretation by the caller.
    static mapnik::raster_ptr read(const uint8_t* wkb, int size, int bnd = 0)
    {
        pgraster_wkb_reader reader(wkb, size, bnd);
        return reader.get_raster();
    }

  private:
    mapnik::raster_ptr read_indexed(mapnik::box2d<double> const& bbox, uint16_t width, uint16_t height);
    mapnik::raster_ptr read_grayscale(mapnik::box2d<double> const& bbox, uint16_t width, uint16_t height);
    mapnik::raster_ptr read_rgba(mapnik::box2d<double> const& bbox, uint16_t width, uint16_t height);

    // int wkbsize_;
    // const uint8_t* wkb_;
    // const uint8_t* wkbend_;
    const uint8_t* ptr_;
    uint8_t endian_;
    int bandno_;
    uint16_t numBands_;
    uint16_t width_;
    uint16_t height_;
};

#endif // PGRASTER_WKB_READER_HPP