QgsRasterBlock* QgsSingleBandColorDataRenderer::block( int bandNo, QgsRectangle  const & extent, int width, int height, QgsRasterBlockFeedback* feedback )
{
  Q_UNUSED( bandNo );

  QgsRasterBlock *outputBlock = new QgsRasterBlock();
  if ( !mInput )
  {
    return outputBlock;
  }

  QgsRasterBlock *inputBlock = mInput->block( mBand, extent, width, height, feedback );
  if ( !inputBlock || inputBlock->isEmpty() )
  {
    QgsDebugMsg( "No raster data!" );
    delete inputBlock;
    return outputBlock;
  }

  bool hasTransparency = usesTransparency();
  if ( !hasTransparency )
  {
    // Nothing to do, just retype if necessary
    inputBlock->convert( Qgis::ARGB32_Premultiplied );
    delete outputBlock;
    return inputBlock;
  }

  if ( !outputBlock->reset( Qgis::ARGB32_Premultiplied, width, height ) )
  {
    delete inputBlock;
    return outputBlock;
  }

  // make sure input is also premultiplied!
  inputBlock->convert( Qgis::ARGB32_Premultiplied );

  QRgb* inputBits = ( QRgb* )inputBlock->bits();
  QRgb* outputBits = ( QRgb* )outputBlock->bits();
  for ( qgssize i = 0; i < ( qgssize )width*height; i++ )
  {
    QRgb c = inputBits[i];
    outputBits[i] = qRgba( mOpacity * qRed( c ), mOpacity * qGreen( c ), mOpacity * qBlue( c ), mOpacity * qAlpha( c ) );
  }

  delete inputBlock;
  return outputBlock;
}
Example #2
0
QgsRasterBlock *QgsRasterDataProvider::block( int bandNo, QgsRectangle  const &boundingBox, int width, int height, QgsRasterBlockFeedback *feedback )
{
  QgsDebugMsgLevel( QString( "bandNo = %1 width = %2 height = %3" ).arg( bandNo ).arg( width ).arg( height ), 4 );
  QgsDebugMsgLevel( QString( "boundingBox = %1" ).arg( boundingBox.toString() ), 4 );

  QgsRasterBlock *block = new QgsRasterBlock( dataType( bandNo ), width, height );
  if ( sourceHasNoDataValue( bandNo ) && useSourceNoDataValue( bandNo ) )
  {
    block->setNoDataValue( sourceNoDataValue( bandNo ) );
  }

  if ( block->isEmpty() )
  {
    QgsDebugMsg( "Couldn't create raster block" );
    return block;
  }

  // Read necessary extent only
  QgsRectangle tmpExtent = extent().intersect( &boundingBox );

  if ( tmpExtent.isEmpty() )
  {
    QgsDebugMsg( "Extent outside provider extent" );
    block->setIsNoData();
    return block;
  }

  double xRes = boundingBox.width() / width;
  double yRes = boundingBox.height() / height;
  double tmpXRes, tmpYRes;
  double providerXRes = 0;
  double providerYRes = 0;
  if ( capabilities() & Size )
  {
    providerXRes = extent().width() / xSize();
    providerYRes = extent().height() / ySize();
    tmpXRes = std::max( providerXRes, xRes );
    tmpYRes = std::max( providerYRes, yRes );
    if ( qgsDoubleNear( tmpXRes, xRes ) ) tmpXRes = xRes;
    if ( qgsDoubleNear( tmpYRes, yRes ) ) tmpYRes = yRes;
  }
  else
  {
    tmpXRes = xRes;
    tmpYRes = yRes;
  }

  if ( tmpExtent != boundingBox ||
       tmpXRes > xRes || tmpYRes > yRes )
  {
    // Read smaller extent or lower resolution

    if ( !extent().contains( boundingBox ) )
    {
      QRect subRect = QgsRasterBlock::subRect( boundingBox, width, height, extent() );
      block->setIsNoDataExcept( subRect );
    }

    // Calculate row/col limits (before tmpExtent is aligned)
    int fromRow = std::round( ( boundingBox.yMaximum() - tmpExtent.yMaximum() ) / yRes );
    int toRow = std::round( ( boundingBox.yMaximum() - tmpExtent.yMinimum() ) / yRes ) - 1;
    int fromCol = std::round( ( tmpExtent.xMinimum() - boundingBox.xMinimum() ) / xRes );
    int toCol = std::round( ( tmpExtent.xMaximum() - boundingBox.xMinimum() ) / xRes ) - 1;

    QgsDebugMsgLevel( QString( "fromRow = %1 toRow = %2 fromCol = %3 toCol = %4" ).arg( fromRow ).arg( toRow ).arg( fromCol ).arg( toCol ), 4 );

    if ( fromRow < 0 || fromRow >= height || toRow < 0 || toRow >= height ||
         fromCol < 0 || fromCol >= width || toCol < 0 || toCol >= width )
    {
      // Should not happen
      QgsDebugMsg( "Row or column limits out of range" );
      return block;
    }

    // If lower source resolution is used, the extent must beS aligned to original
    // resolution to avoid possible shift due to resampling
    if ( tmpXRes > xRes )
    {
      int col = std::floor( ( tmpExtent.xMinimum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMinimum( extent().xMinimum() + col * providerXRes );
      col = std::ceil( ( tmpExtent.xMaximum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMaximum( extent().xMinimum() + col * providerXRes );
    }
    if ( tmpYRes > yRes )
    {
      int row = std::floor( ( extent().yMaximum() - tmpExtent.yMaximum() ) / providerYRes );
      tmpExtent.setYMaximum( extent().yMaximum() - row * providerYRes );
      row = std::ceil( ( extent().yMaximum() - tmpExtent.yMinimum() ) / providerYRes );
      tmpExtent.setYMinimum( extent().yMaximum() - row * providerYRes );
    }
    int tmpWidth = std::round( tmpExtent.width() / tmpXRes );
    int tmpHeight = std::round( tmpExtent.height() / tmpYRes );
    tmpXRes = tmpExtent.width() / tmpWidth;
    tmpYRes = tmpExtent.height() / tmpHeight;

    QgsDebugMsgLevel( QString( "Reading smaller block tmpWidth = %1 height = %2" ).arg( tmpWidth ).arg( tmpHeight ), 4 );
    QgsDebugMsgLevel( QString( "tmpExtent = %1" ).arg( tmpExtent.toString() ), 4 );

    QgsRasterBlock *tmpBlock = new QgsRasterBlock( dataType( bandNo ), tmpWidth, tmpHeight );
    if ( sourceHasNoDataValue( bandNo ) && useSourceNoDataValue( bandNo ) )
    {
      tmpBlock->setNoDataValue( sourceNoDataValue( bandNo ) );
    }

    readBlock( bandNo, tmpExtent, tmpWidth, tmpHeight, tmpBlock->bits(), feedback );

    int pixelSize = dataTypeSize( bandNo );

    double xMin = boundingBox.xMinimum();
    double yMax = boundingBox.yMaximum();
    double tmpXMin = tmpExtent.xMinimum();
    double tmpYMax = tmpExtent.yMaximum();

    for ( int row = fromRow; row <= toRow; row++ )
    {
      double y = yMax - ( row + 0.5 ) * yRes;
      int tmpRow = std::floor( ( tmpYMax - y ) / tmpYRes );

      for ( int col = fromCol; col <= toCol; col++ )
      {
        double x = xMin + ( col + 0.5 ) * xRes;
        int tmpCol = std::floor( ( x - tmpXMin ) / tmpXRes );

        if ( tmpRow < 0 || tmpRow >= tmpHeight || tmpCol < 0 || tmpCol >= tmpWidth )
        {
          QgsDebugMsg( "Source row or column limits out of range" );
          block->setIsNoData(); // so that the problem becomes obvious and fixed
          delete tmpBlock;
          return block;
        }

        qgssize tmpIndex = static_cast< qgssize >( tmpRow ) * static_cast< qgssize >( tmpWidth ) + tmpCol;
        qgssize index = row * static_cast< qgssize >( width ) + col;

        char *tmpBits = tmpBlock->bits( tmpIndex );
        char *bits = block->bits( index );
        if ( !tmpBits )
        {
          QgsDebugMsg( QString( "Cannot get input block data tmpRow = %1 tmpCol = %2 tmpIndex = %3." ).arg( tmpRow ).arg( tmpCol ).arg( tmpIndex ) );
          continue;
        }
        if ( !bits )
        {
          QgsDebugMsg( "Cannot set output block data." );
          continue;
        }
        memcpy( bits, tmpBits, pixelSize );
      }
    }

    delete tmpBlock;
  }
  else
  {
    readBlock( bandNo, boundingBox, width, height, block->bits(), feedback );
  }

  // apply scale and offset
  block->applyScaleOffset( bandScale( bandNo ), bandOffset( bandNo ) );
  // apply user no data values
  block->applyNoDataValues( userNoDataValues( bandNo ) );
  return block;
}
Example #3
0
int QgsGrassGisLib::readRasterRow( int fd, void * buf, int row, RASTER_MAP_TYPE data_type, bool noDataAsZero )
{
    if ( row < 0 || row >= mRows )
    {
        QgsDebugMsg( QString( "row %1 out of range 0 - %2" ).arg( row ).arg( mRows ) );
        return 0;
    }

    // TODO: use cached block with more rows
    Raster raster = mRasters.value( fd );
    //if ( !raster.provider ) return -1;
    if ( !raster.input ) return -1;

    // Create extent for current row
    QgsRectangle blockRect = mExtent;
    double yRes = mExtent.height() / mRows;
    double yMax = mExtent.yMaximum() - yRes * row;
    //QgsDebugMsg( QString( "height = %1 mRows = %2" ).arg( mExtent.height() ).arg( mRows ) );
    //QgsDebugMsg( QString( "row = %1 yRes = %2 yRes * row = %3" ).arg( row ).arg( yRes ).arg( yRes * row ) );
    //QgsDebugMsg( QString( "mExtent.yMaximum() = %1 yMax = %2" ).arg( mExtent.yMaximum() ).arg( yMax ) );
    blockRect.setYMaximum( yMax );
    blockRect.setYMinimum( yMax - yRes );

    QgsRasterBlock *block = raster.input->block( raster.band, blockRect, mColumns, 1 );
    if ( !block ) return -1;

    QGis::DataType requestedType = qgisRasterType( data_type );

    //QgsDebugMsg( QString("data_type = %1").arg(data_type) );
    //QgsDebugMsg( QString("requestedType = %1").arg(requestedType) );
    //QgsDebugMsg( QString("requestedType size = %1").arg( QgsRasterBlock::typeSize( requestedType ) ) );
    //QgsDebugMsg( QString("block->dataType = %1").arg( block->dataType() ) );

    block->convert( requestedType );

    memcpy( buf, block->bits( 0 ), QgsRasterBlock::typeSize( requestedType ) * mColumns );

    for ( int i = 0; i < mColumns; i++ )
    {
        QgsDebugMsgLevel( QString( "row = %1 i = %2 val = %3 isNoData = %4" ).arg( row ).arg( i ).arg( block->value( i ) ).arg( block->isNoData( i ) ), 5 );
        //(( CELL * ) buf )[i] = i;
        if ( block->isNoData( 0, i ) )
        {
            if ( noDataAsZero )
            {
                switch ( data_type )
                {
                case CELL_TYPE:
                    G_zero(( char * ) &(( CELL * ) buf )[i], G_raster_size( data_type ) );
                    break;
                case FCELL_TYPE:
                    G_zero(( char * ) &(( FCELL * ) buf )[i], G_raster_size( data_type ) );
                    break;
                case DCELL_TYPE:
                    G_zero(( char * ) &(( DCELL * ) buf )[i], G_raster_size( data_type ) );
                    break;
                default:
                    break;
                }
            }
            else
            {
                switch ( data_type )
                {
                case CELL_TYPE:
                    G_set_c_null_value( &(( CELL * ) buf )[i], 1 );
                    break;
                case FCELL_TYPE:
                    G_set_f_null_value( &(( FCELL * ) buf )[i], 1 );
                    break;
                case DCELL_TYPE:
                    G_set_d_null_value( &(( DCELL * ) buf )[i], 1 );
                    break;
                default:
                    break;
                }
            }
        }
        //else
        //{
        //memcpy( &( buf[i] ), block->bits( 0, i ), 4 );
        //buf[i] = (int)  block->value( 0, i);
        //QgsDebugMsg( QString("buf[i] = %1").arg(buf[i]));
        //}
    }
    delete block;
    return 1;

}
QgsRasterBlock * QgsPalettedRasterRenderer::block( int bandNo, QgsRectangle  const & extent, int width, int height )
{
    QgsRasterBlock *outputBlock = new QgsRasterBlock();
    if ( !mInput )
    {
        return outputBlock;
    }

    QgsRasterBlock *inputBlock = mInput->block( bandNo, extent, width, height );

    if ( !inputBlock || inputBlock->isEmpty() )
    {
        QgsDebugMsg( "No raster data!" );
        delete inputBlock;
        return outputBlock;
    }

    double currentOpacity = mOpacity;

    //rendering is faster without considering user-defined transparency
    bool hasTransparency = usesTransparency();
    QgsRasterBlock *alphaBlock = 0;

    if ( mAlphaBand > 0 && mAlphaBand != mBand )
    {
        alphaBlock = mInput->block( mAlphaBand, extent, width, height );
        if ( !alphaBlock || alphaBlock->isEmpty() )
        {
            delete inputBlock;
            delete alphaBlock;
            return outputBlock;
        }
    }
    else if ( mAlphaBand == mBand )
    {
        alphaBlock = inputBlock;
    }

    if ( !outputBlock->reset( QGis::ARGB32_Premultiplied, width, height ) )
    {
        delete inputBlock;
        delete alphaBlock;
        return outputBlock;
    }

    QRgb myDefaultColor = NODATA_COLOR;

    //use direct data access instead of QgsRasterBlock::setValue
    //because of performance
    unsigned int* outputData = ( unsigned int* )( outputBlock->bits() );

    qgssize rasterSize = ( qgssize )width * height;
    for ( qgssize i = 0; i < rasterSize; ++i )
    {
        if ( inputBlock->isNoData( i ) )
        {
            outputData[i] = myDefaultColor;
            continue;
        }
        int val = ( int ) inputBlock->value( i );
        if ( !hasTransparency )
        {
            outputData[i] = mColors[val];
        }
        else
        {
            currentOpacity = mOpacity;
            if ( mRasterTransparency )
            {
                currentOpacity = mRasterTransparency->alphaValue( val, mOpacity * 255 ) / 255.0;
            }
            if ( mAlphaBand > 0 )
            {
                currentOpacity *=  alphaBlock->value( i ) / 255.0;
            }
            QColor currentColor = QColor( mColors[val] );
            outputData[i] = qRgba( currentOpacity * currentColor.red(), currentOpacity * currentColor.green(), currentOpacity * currentColor.blue(), currentOpacity * 255 );
        }
    }

    delete inputBlock;
    if ( mAlphaBand > 0 && mBand != mAlphaBand )
    {
        delete alphaBlock;
    }

    return outputBlock;
}
Example #5
0
QgsRasterBlock * QgsRasterProjector::block( int bandNo, QgsRectangle  const & extent, int width, int height )
{
  QgsDebugMsg( QString( "extent:\n%1" ).arg( extent.toString() ) );
  QgsDebugMsg( QString( "width = %1 height = %2" ).arg( width ).arg( height ) );
  if ( !mInput )
  {
    QgsDebugMsg( "Input not set" );
    return new QgsRasterBlock();
  }

  if ( ! mSrcCRS.isValid() || ! mDestCRS.isValid() || mSrcCRS == mDestCRS )
  {
    QgsDebugMsg( "No projection necessary" );
    return mInput->block( bandNo, extent, width, height );
  }

  mDestExtent = extent;
  mDestRows = height;
  mDestCols = width;
  calc();

  QgsDebugMsg( QString( "srcExtent:\n%1" ).arg( srcExtent().toString() ) );
  QgsDebugMsg( QString( "srcCols = %1 srcRows = %2" ).arg( srcCols() ).arg( srcRows() ) );

  // If we zoom out too much, projector srcRows / srcCols maybe 0, which can cause problems in providers
  if ( srcRows() <= 0 || srcCols() <= 0 )
  {
    QgsDebugMsg( "Zero srcRows or srcCols" );
    return new QgsRasterBlock();
  }

  QgsRasterBlock *inputBlock = mInput->block( bandNo, srcExtent(), srcCols(), srcRows() );
  if ( !inputBlock || inputBlock->isEmpty() )
  {
    QgsDebugMsg( "No raster data!" );
    delete inputBlock;
    return new QgsRasterBlock();
  }

  qgssize pixelSize = QgsRasterBlock::typeSize( mInput->dataType( bandNo ) );

  QgsRasterBlock *outputBlock;
  if ( inputBlock->hasNoDataValue() )
  {
    outputBlock = new QgsRasterBlock( inputBlock->dataType(), width, height, inputBlock->noDataValue() );
  }
  else
  {
    outputBlock = new QgsRasterBlock( inputBlock->dataType(), width, height );
  }
  if ( !outputBlock->isValid() )
  {
    QgsDebugMsg( "Cannot create block" );
    delete inputBlock;
    return outputBlock;
  }

  // set output to no data, it should be fast
  outputBlock->setIsNoData();

  // No data: because isNoData()/setIsNoData() is slow with respect to simple memcpy,
  // we use if only if necessary:
  // 1) no data value exists (numerical) -> memcpy, not necessary isNoData()/setIsNoData()
  // 2) no data value does not exist but it may contain no data (numerical no data bitmap)
  //    -> must use isNoData()/setIsNoData()
  // 3) no data are not used (no no data value, no no data bitmap) -> simple memcpy
  // 4) image - simple memcpy

  // To copy no data values stored in bitmaps we have to use isNoData()/setIsNoData(),
  // we cannot fill output block with no data because we use memcpy for data, not setValue().
  bool doNoData = !QgsRasterBlock::typeIsNumeric( inputBlock->dataType() ) && inputBlock->hasNoData() && !inputBlock->hasNoDataValue();

  const QgsCoordinateTransform* inverseCt = nullptr;
  if ( !mApproximate )
  {
    inverseCt = QgsCoordinateTransformCache::instance()->transform( mDestCRS.authid(), mSrcCRS.authid(), mDestDatumTransform, mSrcDatumTransform );
  }

  outputBlock->setIsNoData();

  int srcRow, srcCol;
  for ( int i = 0; i < height; ++i )
  {
    for ( int j = 0; j < width; ++j )
    {
      bool inside = srcRowCol( i, j, &srcRow, &srcCol, inverseCt );
      if ( !inside ) continue; // we have everything set to no data

      qgssize srcIndex = ( qgssize )srcRow * mSrcCols + srcCol;
      QgsDebugMsgLevel( QString( "row = %1 col = %2 srcRow = %3 srcCol = %4" ).arg( i ).arg( j ).arg( srcRow ).arg( srcCol ), 5 );

      // isNoData() may be slow so we check doNoData first
      if ( doNoData && inputBlock->isNoData( srcRow, srcCol ) )
      {
        outputBlock->setIsNoData( i, j );
        continue;
      }

      qgssize destIndex = ( qgssize )i * width + j;
      char *srcBits = inputBlock->bits( srcIndex );
      char *destBits = outputBlock->bits( destIndex );
      if ( !srcBits )
      {
        QgsDebugMsg( QString( "Cannot get input block data: row = %1 col = %2" ).arg( i ).arg( j ) );
        continue;
      }
      if ( !destBits )
      {
        QgsDebugMsg( QString( "Cannot set output block data: srcRow = %1 srcCol = %2" ).arg( srcRow ).arg( srcCol ) );
        continue;
      }
      memcpy( destBits, srcBits, pixelSize );
      outputBlock->setIsData( i, j );
    }
  }

  delete inputBlock;

  return outputBlock;
}
Example #6
0
bool QgsGrassRasterImport::import()
{
  QgsDebugMsg( "entered" );
  if ( !mPipe )
  {
    setError( "Pipe is null." );
    return false;
  }

  QgsRasterDataProvider * provider = mPipe->provider();
  if ( !provider )
  {
    setError( "Pipe has no provider." );
    return false;
  }

  if ( !provider->isValid() )
  {
    setError( "Provider is not valid." );
    return false;
  }

  int redBand = 0;
  int greenBand = 0;
  int blueBand = 0;
  for ( int band = 1; band <= provider->bandCount(); band++ )
  {
    QgsDebugMsg( QString( "band = %1" ).arg( band ) );
    int colorInterpretation = provider->colorInterpretation( band );
    if ( colorInterpretation ==  QgsRaster::RedBand )
    {
      redBand = band;
    }
    else if ( colorInterpretation ==  QgsRaster::GreenBand )
    {
      greenBand = band;
    }
    else if ( colorInterpretation ==  QgsRaster::BlueBand )
    {
      blueBand = band;
    }

    QGis::DataType qgis_out_type = QGis::UnknownDataType;
    RASTER_MAP_TYPE data_type = -1;
    switch ( provider->dataType( band ) )
    {
      case QGis::Byte:
      case QGis::UInt16:
      case QGis::Int16:
      case QGis::UInt32:
      case QGis::Int32:
        qgis_out_type = QGis::Int32;
        break;
      case QGis::Float32:
        qgis_out_type = QGis::Float32;
        break;
      case QGis::Float64:
        qgis_out_type = QGis::Float64;
        break;
      case QGis::ARGB32:
      case QGis::ARGB32_Premultiplied:
        qgis_out_type = QGis::Int32;  // split to multiple bands?
        break;
      case QGis::CInt16:
      case QGis::CInt32:
      case QGis::CFloat32:
      case QGis::CFloat64:
      case QGis::UnknownDataType:
        setError( tr( "Data type %1 not supported" ).arg( provider->dataType( band ) ) );
        return false;
    }

    QgsDebugMsg( QString( "data_type = %1" ).arg( data_type ) );

    QString module = QgsGrass::qgisGrassModulePath() + "/qgis.r.in";
    QStringList arguments;
    QString name = mGrassObject.name();
    if ( provider->bandCount() > 1 )
    {
      // raster.<band> to keep in sync with r.in.gdal
      name += QString( ".%1" ).arg( band );
    }
    arguments.append( "output=" + name );    // get list of all output names
    QTemporaryFile gisrcFile;
    QProcess* process = 0;
    try
    {
      process = QgsGrass::startModule( mGrassObject.gisdbase(), mGrassObject.location(), mGrassObject.mapset(), module, arguments, gisrcFile );
    }
    catch ( QgsGrass::Exception &e )
    {
      setError( e.what() );
      return false;
    }

    QDataStream outStream( process );

    outStream << mExtent << ( qint32 )mXSize << ( qint32 )mYSize;
    outStream << ( qint32 )qgis_out_type;

    // calculate reasonable block size (5MB)
    int maximumTileHeight = 5000000 / mXSize;
    maximumTileHeight = std::max( 1, maximumTileHeight );
    // smaller if reprojecting so that it can be canceled quickly
    if ( mPipe->projector() )
    {
      maximumTileHeight = std::max( 1, 100000 / mXSize );
    }

    QgsRasterIterator iter( mPipe->last() );
    iter.setMaximumTileWidth( mXSize );
    iter.setMaximumTileHeight( maximumTileHeight );

    iter.startRasterRead( band, mXSize, mYSize, mExtent );

    int iterLeft = 0;
    int iterTop = 0;
    int iterCols = 0;
    int iterRows = 0;
    QgsRasterBlock* block = 0;
    process->setReadChannel( QProcess::StandardOutput );
    while ( iter.readNextRasterPart( band, iterCols, iterRows, &block, iterLeft, iterTop ) )
    {
      for ( int row = 0; row < iterRows; row++ )
      {
        if ( !block->convert( qgis_out_type ) )
        {
          setError( tr( "Cannot convert block (%1) to data type %2" ).arg( block->toString() ).arg( qgis_out_type ) );
          delete block;
          return false;
        }
        // prepare null values
        double noDataValue;
        if ( block->hasNoDataValue() )
        {
          noDataValue = block->noDataValue();
        }
        else
        {
          switch ( qgis_out_type )
          {
            case QGis::Int32:
              noDataValue = -2147483648.0;
              break;
            case QGis::Float32:
              noDataValue = std::numeric_limits<float>::max() * -1.0;
              break;
            case QGis::Float64:
              noDataValue = std::numeric_limits<double>::max() * -1.0;
              break;
            default: // should not happen
              noDataValue = std::numeric_limits<double>::max() * -1.0;
          }
          for ( qgssize i = 0; i < ( qgssize )block->width()*block->height(); i++ )
          {
            if ( block->isNoData( i ) )
            {
              block->setValue( i, noDataValue );
            }
          }
        }

        char * data = block->bits( row, 0 );
        int size = iterCols * block->dataTypeSize();
        QByteArray byteArray = QByteArray::fromRawData( data, size ); // does not copy data and does not take ownership
        if ( isCanceled() )
        {
          outStream << true; // cancel module
          break;
        }
        outStream << false; // not canceled
        outStream << noDataValue;

        outStream << byteArray;

        // Without waitForBytesWritten() it does not finish ok on Windows (process timeout)
        process->waitForBytesWritten( -1 );

#ifndef Q_OS_WIN
        // wait until the row is written to allow quick cancel (don't send data to buffer)
        process->waitForReadyRead();
        bool result;
        outStream >> result;
#endif
      }
      delete block;
      if ( isCanceled() )
      {
        outStream << true; // cancel module
        break;
      }
    }

    // TODO: send something back from module and read it here to close map correctly in module

    process->closeWriteChannel();
    // TODO: best timeout?
    process->waitForFinished( 30000 );

    QString stdoutString = process->readAllStandardOutput().data();
    QString stderrString = process->readAllStandardError().data();

    QString processResult = QString( "exitStatus=%1, exitCode=%2, error=%3, errorString=%4 stdout=%5, stderr=%6" )
                            .arg( process->exitStatus() ).arg( process->exitCode() )
                            .arg( process->error() ).arg( process->errorString() )
                            .arg( stdoutString.replace( "\n", ", " ) ).arg( stderrString.replace( "\n", ", " ) );
    QgsDebugMsg( "processResult: " + processResult );

    if ( process->exitStatus() != QProcess::NormalExit )
    {
      setError( process->errorString() );
      delete process;
      return false;
    }

    if ( process->exitCode() != 0 )
    {
      setError( stderrString );
      delete process;
      return false;
    }

    delete process;
  }
  QgsDebugMsg( QString( "redBand = %1 greenBand = %2 blueBand = %3" ).arg( redBand ).arg( greenBand ).arg( blueBand ) );
  if ( redBand > 0 && greenBand > 0 && blueBand > 0 )
  {
    // TODO: check if the group exists
    // I_find_group()
    QString name = mGrassObject.name();

    G_TRY
    {
      QgsGrass::setMapset( mGrassObject.gisdbase(), mGrassObject.location(), mGrassObject.mapset() );
      struct Ref ref;
      I_get_group_ref( name.toUtf8().data(), &ref );
      QString redName = name + QString( ".%1" ).arg( redBand );
      QString greenName = name + QString( ".%1" ).arg( greenBand );
      QString blueName = name + QString( ".%1" ).arg( blueBand );
      I_add_file_to_group_ref( redName.toUtf8().data(), mGrassObject.mapset().toUtf8().data(), &ref );
      I_add_file_to_group_ref( greenName.toUtf8().data(), mGrassObject.mapset().toUtf8().data(), &ref );
      I_add_file_to_group_ref( blueName.toUtf8().data(), mGrassObject.mapset().toUtf8().data(), &ref );
      I_put_group_ref( name.toUtf8().data(), &ref );
    }
    G_CATCH( QgsGrass::Exception &e )
    {
      QgsDebugMsg( QString( "Cannot create group: %1" ).arg( e.what() ) );
    }
QgsRasterBlock * QgsRasterDataProvider::block( int theBandNo, QgsRectangle  const & theExtent, int theWidth, int theHeight )
{
  QgsDebugMsg( QString( "theBandNo = %1 theWidth = %2 theHeight = %3" ).arg( theBandNo ).arg( theWidth ).arg( theHeight ) );
  QgsDebugMsg( QString( "theExtent = %1" ).arg( theExtent.toString() ) );

  QgsRasterBlock *block = new QgsRasterBlock( dataType( theBandNo ), theWidth, theHeight, noDataValue( theBandNo ) );

  if ( block->isEmpty() )
  {
    QgsDebugMsg( "Couldn't create raster block" );
    return block;
  }

  // Read necessary extent only
  QgsRectangle tmpExtent = extent().intersect( &theExtent );

  if ( tmpExtent.isEmpty() )
  {
    QgsDebugMsg( "Extent outside provider extent" );
    block->setIsNoData();
    return block;
  }

  double xRes = theExtent.width() / theWidth;
  double yRes = theExtent.height() / theHeight;
  double tmpXRes, tmpYRes;
  double providerXRes = 0;
  double providerYRes = 0;
  if ( capabilities() & ExactResolution )
  {
    providerXRes = extent().width() / xSize();
    providerYRes = extent().height() / ySize();
    tmpXRes = qMax( providerXRes, xRes );
    tmpYRes = qMax( providerYRes, yRes );
    if ( doubleNear( tmpXRes, xRes ) ) tmpXRes = xRes;
    if ( doubleNear( tmpYRes, yRes ) ) tmpYRes = yRes;
  }
  else
  {
    tmpXRes = xRes;
    tmpYRes = yRes;
  }

  if ( tmpExtent != theExtent ||
       tmpXRes > xRes || tmpYRes > yRes )
  {
    // Read smaller extent or lower resolution

    // Calculate row/col limits (before tmpExtent is aligned)
    int fromRow = qRound(( theExtent.yMaximum() - tmpExtent.yMaximum() ) / yRes );
    int toRow = qRound(( theExtent.yMaximum() - tmpExtent.yMinimum() ) / yRes ) - 1;
    int fromCol = qRound(( tmpExtent.xMinimum() - theExtent.xMinimum() ) / xRes ) ;
    int toCol = qRound(( tmpExtent.xMaximum() - theExtent.xMinimum() ) / xRes ) - 1;

    QgsDebugMsg( QString( "fromRow = %1 toRow = %2 fromCol = %3 toCol = %4" ).arg( fromRow ).arg( toRow ).arg( fromCol ).arg( toCol ) );

    if ( fromRow < 0 || fromRow >= theHeight || toRow < 0 || toRow >= theHeight ||
         fromCol < 0 || fromCol >= theWidth || toCol < 0 || toCol >= theWidth )
    {
      // Should not happen
      QgsDebugMsg( "Row or column limits out of range" );
      return block;
    }

    // If lower source resolution is used, the extent must beS aligned to original
    // resolution to avoid possible shift due to resampling
    if ( tmpXRes > xRes )
    {
      int col = floor(( tmpExtent.xMinimum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMinimum( extent().xMinimum() + col * providerXRes );
      col = ceil(( tmpExtent.xMaximum() - extent().xMinimum() ) / providerXRes );
      tmpExtent.setXMaximum( extent().xMinimum() + col * providerXRes );
    }
    if ( tmpYRes > yRes )
    {
      int row = floor(( extent().yMaximum() - tmpExtent.yMaximum() ) / providerYRes );
      tmpExtent.setYMaximum( extent().yMaximum() - row * providerYRes );
      row = ceil(( extent().yMaximum() - tmpExtent.yMinimum() ) / providerYRes );
      tmpExtent.setYMinimum( extent().yMaximum() - row * providerYRes );
    }
    int tmpWidth = qRound( tmpExtent.width() / tmpXRes );
    int tmpHeight = qRound( tmpExtent.height() / tmpYRes );
    tmpXRes = tmpExtent.width() / tmpWidth;
    tmpYRes = tmpExtent.height() / tmpHeight;

    QgsDebugMsg( QString( "Reading smaller block tmpWidth = %1 theHeight = %2" ).arg( tmpWidth ).arg( tmpHeight ) );
    QgsDebugMsg( QString( "tmpExtent = %1" ).arg( tmpExtent.toString() ) );

    block->setIsNoData();

    QgsRasterBlock *tmpBlock = new QgsRasterBlock( dataType( theBandNo ), tmpWidth, tmpHeight, noDataValue( theBandNo ) );

    readBlock( theBandNo, tmpExtent, tmpWidth, tmpHeight, tmpBlock->data() );

    int pixelSize = dataTypeSize( theBandNo );

    double xMin = theExtent.xMinimum();
    double yMax = theExtent.yMaximum();
    double tmpXMin = tmpExtent.xMinimum();
    double tmpYMax = tmpExtent.yMaximum();

    for ( int row = fromRow; row <= toRow; row++ )
    {
      double y = yMax - ( row + 0.5 ) * yRes;
      int tmpRow = floor(( tmpYMax - y ) / tmpYRes );

      for ( int col = fromCol; col <= toCol; col++ )
      {
        double x = xMin + ( col + 0.5 ) * xRes;
        int tmpCol = floor(( x - tmpXMin ) / tmpXRes );

        if ( tmpRow < 0 || tmpRow >= tmpHeight || tmpCol < 0 || tmpCol >= tmpWidth )
        {
          QgsDebugMsg( "Source row or column limits out of range" );
          block->setIsNoData(); // so that the problem becomes obvious and fixed
          delete tmpBlock;
          return block;
        }

        size_t tmpIndex = tmpRow * tmpWidth + tmpCol;
        size_t index = row * theWidth + col;

        char *tmpBits = tmpBlock->bits( tmpIndex );
        char *bits = block->bits( index );
        if ( !tmpBits )
        {
          QgsDebugMsg( QString( "Cannot get input block data tmpRow = %1 tmpCol = %2 tmpIndex = %3." ).arg( tmpRow ).arg( tmpCol ).arg( tmpIndex ) );
          continue;
        }
        if ( !bits )
        {
          QgsDebugMsg( "Cannot set output block data." );
          continue;
        }
        memcpy( bits, tmpBits, pixelSize );
      }
    }

    delete tmpBlock;
  }
  else
  {
    readBlock( theBandNo, theExtent, theWidth, theHeight, block->data() );
  }

  // apply user no data values
  // TODO: there are other readBlock methods where no data are not applied
  block->applyNodataValues( userNoDataValue( theBandNo ) );
  return block;
}