qgsrasteriterator.h

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/***************************************************************************
    qgsrasteriterator.h
    ---------------------
    begin                : July 2012
    copyright            : (C) 2012 by Marco Hugentobler
    email                : marco dot hugentobler at sourcepole dot ch
 ***************************************************************************
 *                                                                         *
 *   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 QGSRASTERITERATOR_H
#define QGSRASTERITERATOR_H

#include "qgis_core.h"
#include "qgsrectangle.h"
#include "qgis_sip.h"
#include <QMap>

class QgsMapToPixel;
class QgsRasterBlock;
class QgsRasterBlockFeedback;
class QgsRasterInterface;
class QgsRasterProjector;
struct QgsRasterViewPort;

class CORE_EXPORT QgsRasterIterator
{
  public:

    QgsRasterIterator( QgsRasterInterface *input );

    void startRasterRead( int bandNumber, int nCols, int nRows, const QgsRectangle &extent, QgsRasterBlockFeedback *feedback = nullptr );

    bool next( int bandNumber, int &columns SIP_OUT, int &rows SIP_OUT, int &topLeftColumn SIP_OUT, int &topLeftRow SIP_OUT, QgsRectangle &blockExtent SIP_OUT );

    bool readNextRasterPart( int bandNumber,
                             int &nCols, int &nRows,
                             QgsRasterBlock **block,
                             int &topLeftCol, int &topLeftRow );

    bool readNextRasterPart( int bandNumber,
                             int &nCols, int &nRows,
                             std::unique_ptr< QgsRasterBlock > &block,
                             int &topLeftCol, int &topLeftRow,
                             QgsRectangle *blockExtent = nullptr ) SIP_SKIP;

    void stopRasterRead( int bandNumber );

    const QgsRasterInterface *input() const { return mInput; }

    void setMaximumTileWidth( int w ) { mMaximumTileWidth = w; }

    int maximumTileWidth() const { return mMaximumTileWidth; }

    void setMaximumTileHeight( int h ) { mMaximumTileHeight = h; }

    int maximumTileHeight() const { return mMaximumTileHeight; }

    static const int DEFAULT_MAXIMUM_TILE_WIDTH = 2000;

    static const int DEFAULT_MAXIMUM_TILE_HEIGHT = 2000;

  private:
    //Stores information about reading of a raster band. Columns and rows are in unsampled coordinates
    struct RasterPartInfo
    {
      int currentCol;
      int currentRow;
      int nCols;
      int nRows;
    };

    QgsRasterInterface *mInput = nullptr;
    QMap<int, RasterPartInfo> mRasterPartInfos;
    QgsRectangle mExtent;
    QgsRasterBlockFeedback *mFeedback = nullptr;

    int mMaximumTileWidth;
    int mMaximumTileHeight;

    void removePartInfo( int bandNumber );
    bool readNextRasterPartInternal( int bandNumber, int &nCols, int &nRows, std::unique_ptr<QgsRasterBlock> *block, int &topLeftCol, int &topLeftRow, QgsRectangle *blockExtent );
};

#endif // QGSRASTERITERATOR_H