qgsterraindownloader.h

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/***************************************************************************
  qgsterraindownloader.h
  --------------------------------------
  Date                 : March 2019
  Copyright            : (C) 2019 by Martin Dobias
  Email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSTERRAINDOWNLOADER_H
#define QGSTERRAINDOWNLOADER_H

#include "qgis_3d.h"

#include <memory>
#include <QByteArray>
#include <QImage>

#include "qgscoordinatetransformcontext.h"

class QgsRectangle;
class QgsCoordinateReferenceSystem;
class QgsRasterLayer;
class QgsCoordinateTransformContext;

class _3D_EXPORT QgsTerrainDownloader
{

  public:

    QgsTerrainDownloader( const QgsCoordinateTransformContext  &transformContext );

    ~QgsTerrainDownloader();

    typedef struct
    {
      QString uri;  
      int zMin = 0;  
      int zMax = 0;  
    } DataSource;

    static DataSource defaultDataSource();

    void setDataSource( const DataSource &ds );

    DataSource dataSource() const { return mDataSource; }

    QByteArray getHeightMap( const QgsRectangle &extentOrig, int res, const QgsCoordinateReferenceSystem &destCrs, const QgsCoordinateTransformContext &context = QgsCoordinateTransformContext(), QString tmpFilenameImg = QString(), QString tmpFilenameTif = QString() );

  private:

    double findBestTileResolution( double requestedMupp );

    static void adjustExtentAndResolution( double mupp, const QgsRectangle &extentOrig, QgsRectangle &extent, int &res );

    static void tileImageToHeightMap( const QImage &img, QByteArray &heightMap );

  private:
    DataSource mDataSource;
    std::unique_ptr<QgsRasterLayer> mOnlineDtm;
    double mXSpan = 0;   
};

#endif // QGSTERRAINDOWNLOADER_H