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 "qgis_sip.h"
#include "qgsrectangle.h"
 
#include <QMap>
 
class QgsMapToPixel;
class QgsRasterBlock;
class QgsRasterBlockFeedback;
class QgsRasterInterface;
class QgsRasterProjector;
struct QgsRasterViewPort;

class CORE_EXPORT QgsRasterIterator
{
  public:
    QgsRasterIterator( QgsRasterInterface *input, int tileOverlapPixels = 0 );

    void setSnapToPixelFactor( int factor ) { mSnapToPixelFactor = factor > 0 ? factor : 1; }

    int snapToPixelFactor() const { return mSnapToPixelFactor; }

    static QgsRectangle subRegion(
      const QgsRectangle &rasterExtent,
      int rasterWidth,
      int rasterHeight,
      const QgsRectangle &subRegion,
      int &subRegionWidth SIP_OUT,
      int &subRegionHeight SIP_OUT,
      int &subRegionLeft SIP_OUT,
      int &subRegionTop SIP_OUT,
      int resamplingFactor = 1
    );

    void startRasterRead( int bandNumber, qgssize nCols, qgssize 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 SIP_TRANSFERBACK, int &topLeftCol, int &topLeftRow );

    bool readNextRasterPart(
      int bandNumber,
      int &nCols,
      int &nRows,
      std::unique_ptr< QgsRasterBlock > &block,
      int &topLeftCol,
      int &topLeftRow,
      QgsRectangle *blockExtent = nullptr,
      int *tileColumns = nullptr,
      int *tileRows = nullptr,
      int *tileTopLeftColumn = nullptr,
      int *tileTopLeftRow = 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; }

    int blockCountWidth() const { return mNumberBlocksWidth; }

    int blockCountHeight() const { return mNumberBlocksHeight; }

    qgssize blockCount() const { return static_cast< qgssize >( mNumberBlocksHeight ) * mNumberBlocksWidth; }

    double progress( int bandNumber, double currentBlockProgress = -1 ) const;

    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
    {
        qgssize currentCol;
        qgssize currentRow;
        qgssize nCols;
        qgssize nRows;
        qgssize iteratedPixels = 0;
        qgssize previousIteratedPixels = 0;
        qgssize currentBlockSize = 0;
    };
 
    QgsRasterInterface *mInput = nullptr;
    QMap<int, RasterPartInfo> mRasterPartInfos;
    QgsRectangle mExtent;
    QgsRasterBlockFeedback *mFeedback = nullptr;
 
    int mTileOverlapPixels = 0;
    int mMaximumTileWidth;
    int mMaximumTileHeight;
    int mSnapToPixelFactor = 1;
 
    int mNumberBlocksWidth = 0;
    int mNumberBlocksHeight = 0;

    void removePartInfo( int bandNumber );
    bool readNextRasterPartInternal(
      int bandNumber,
      int &nCols,
      int &nRows,
      std::unique_ptr<QgsRasterBlock> *block,
      int &topLeftCol,
      int &topLeftRow,
      QgsRectangle *blockExtent,
      int &tileColumns,
      int &tileRows,
      int &tileTopLeftColumn,
      int &tileTopLeftRow
    );
};
 
#endif // QGSRASTERITERATOR_H