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Commit 3f1056a

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mhugentmhugent
committedJul 7, 2012
Added class QgsRasterIterator
·
ltr-3_40Before-merge-new_vector_api
1 parent 2b53f49 commit 3f1056a

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‎src/core/CMakeLists.txt

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@@ -161,6 +161,7 @@ SET(QGIS_CORE_SRCS
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raster/qgslinearminmaxenhancementwithclip.cpp
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raster/qgspseudocolorshader.cpp
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raster/qgsrasterinterface.cpp
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raster/qgsrasteriterator.cpp
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raster/qgsrasterlayer.cpp
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raster/qgsrastertransparency.cpp
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raster/qgsrasterpipe.cpp

‎src/core/raster/qgsrasteriterator.cpp

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#include "qgsrasteriterator.h"
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#include "qgsrasterinterface.h"
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#include "qgsrasterprojector.h"
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#include "qgsrasterviewport.h"
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QgsRasterIterator::QgsRasterIterator( QgsRasterInterface* input ): mInput( input )
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{
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}
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QgsRasterIterator::~QgsRasterIterator()
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{
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}
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void QgsRasterIterator::startRasterRead( int bandNumber, QgsRasterViewPort* viewPort, const QgsMapToPixel* mapToPixel )
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{
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if ( !viewPort || !mapToPixel || !mInput )
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{
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return;
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}
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//remove any previous part on that band
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removePartInfo( bandNumber );
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//split raster into small portions if necessary
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RasterPartInfo pInfo;
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pInfo.nCols = viewPort->drawableAreaXDim;
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pInfo.nRows = viewPort->drawableAreaYDim;
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//effective oversampling factors are different to global one because of rounding
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//oversamplingX = (( double )pInfo.nCols * oversampling ) / viewPort->drawableAreaXDim;
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//oversamplingY = (( double )pInfo.nRows * oversampling ) / viewPort->drawableAreaYDim;
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// TODO : we dont know oversampling (grid size) here - how to get totalMemoryUsage ?
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//int totalMemoryUsage = pInfo.nCols * oversamplingX * pInfo.nRows * oversamplingY * mInput->dataTypeSize( bandNumber );
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int totalMemoryUsage = pInfo.nCols * pInfo.nRows * mInput->dataTypeSize( bandNumber );
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int parts = totalMemoryUsage / 100000000 + 1;
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int nPartsPerDimension = sqrt( parts );
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pInfo.nColsPerPart = pInfo.nCols / nPartsPerDimension;
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pInfo.nRowsPerPart = pInfo.nRows / nPartsPerDimension;
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pInfo.currentCol = 0;
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pInfo.currentRow = 0;
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pInfo.data = 0;
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pInfo.prj = 0;
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mRasterPartInfos.insert( bandNumber, pInfo );
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}
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bool QgsRasterIterator::readNextRasterPart( int bandNumber, QgsRasterViewPort* viewPort,
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int& nCols, int& nRows,
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void** rasterData,
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int& topLeftCol, int& topLeftRow )
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{
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if ( !viewPort )
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{
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return false;
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}
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//get partinfo
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QMap<int, RasterPartInfo>::iterator partIt = mRasterPartInfos.find( bandNumber );
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if ( partIt == mRasterPartInfos.end() )
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{
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return false;
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}
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RasterPartInfo& pInfo = partIt.value();
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//remove last data block
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// TODO: data are released somewhere else (check)
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//free( pInfo.data );
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pInfo.data = 0;
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delete pInfo.prj;
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pInfo.prj = 0;
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//already at end
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if ( pInfo.currentCol == pInfo.nCols && pInfo.currentRow == pInfo.nRows )
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{
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return false;
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}
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//read data block
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nCols = qMin( pInfo.nColsPerPart, pInfo.nCols - pInfo.currentCol );
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nRows = qMin( pInfo.nRowsPerPart, pInfo.nRows - pInfo.currentRow );
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//get subrectangle
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QgsRectangle viewPortExtent = viewPort->mDrawnExtent;
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double xmin = viewPortExtent.xMinimum() + pInfo.currentCol / ( double )pInfo.nCols * viewPortExtent.width();
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double xmax = viewPortExtent.xMinimum() + ( pInfo.currentCol + nCols ) / ( double )pInfo.nCols * viewPortExtent.width();
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double ymin = viewPortExtent.yMaximum() - ( pInfo.currentRow + nRows ) / ( double )pInfo.nRows * viewPortExtent.height();
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double ymax = viewPortExtent.yMaximum() - pInfo.currentRow / ( double )pInfo.nRows * viewPortExtent.height();
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QgsRectangle blockRect( xmin, ymin, xmax, ymax );
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pInfo.data = mInput->block( bandNumber, blockRect, nCols, nRows );
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*rasterData = pInfo.data;
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topLeftCol = pInfo.currentCol;
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topLeftRow = pInfo.currentRow;
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pInfo.currentCol += nCols;
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if ( pInfo.currentCol == pInfo.nCols && pInfo.currentRow + nRows == pInfo.nRows ) //end of raster
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{
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pInfo.currentRow = pInfo.nRows;
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}
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else if ( pInfo.currentCol == pInfo.nCols ) //start new row
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{
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pInfo.currentCol = 0;
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pInfo.currentRow += pInfo.nRowsPerPart;
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}
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return true;
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}
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void QgsRasterIterator::stopRasterRead( int bandNumber )
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{
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removePartInfo( bandNumber );
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}
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void QgsRasterIterator::removePartInfo( int bandNumber )
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{
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QMap<int, RasterPartInfo>::iterator partIt = mRasterPartInfos.find( bandNumber );
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if ( partIt != mRasterPartInfos.end() )
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{
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RasterPartInfo& pInfo = partIt.value();
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//CPLFree( pInfo.data );
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free( pInfo.data );
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delete pInfo.prj;
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mRasterPartInfos.remove( bandNumber );
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}
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}

‎src/core/raster/qgsrasteriterator.h

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#ifndef QGSRASTERITERATOR_H
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#define QGSRASTERITERATOR_H
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#include <QMap>
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class QgsMapToPixel;
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class QgsRasterInterface;
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class QgsRasterProjector;
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class QgsRasterViewPort;
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class QgsRasterIterator
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{
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public:
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//Stores information about reading of a raster band. Columns and rows are in unsampled coordinates
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struct RasterPartInfo
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{
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int currentCol;
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int currentRow;
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int nCols;
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int nRows;
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int nColsPerPart;
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int nRowsPerPart;
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void* data; //data (can be in oversampled/undersampled resolution)
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QgsRasterProjector* prj; //raster projector (or 0 if no reprojection is done)
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};
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QgsRasterIterator( QgsRasterInterface* input );
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~QgsRasterIterator();
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/**Start reading of raster band. Raster data can then be retrieved by calling readNextRasterPart until it returns false.
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@param bandNumer number of raster band to read
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@param viewPort describes raster position on screen
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*/
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void startRasterRead( int bandNumber, QgsRasterViewPort* viewPort, const QgsMapToPixel* mapToPixel );
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/**Fetches next part of raster data
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@param nCols number of columns on output device
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@param nRows number of rows on output device
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@param nColsRaster number of raster columns (different to nCols if oversamplingX != 1.0)
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@param nRowsRaster number of raster rows (different to nRows if oversamplingY != 0)*/
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bool readNextRasterPart( int bandNumber, QgsRasterViewPort* viewPort,
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int& nCols, int& nRows,
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void** rasterData,
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int& topLeftCol, int& topLeftRow );
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void stopRasterRead( int bandNumber );
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private:
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QgsRasterInterface* mInput;
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QMap<int, RasterPartInfo> mRasterPartInfos;
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/**Remove part into and release memory*/
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void removePartInfo( int bandNumber );
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};
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#endif // QGSRASTERITERATOR_H

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