otbImageRegionTileMapSplitter.txx

/*=========================================================================

Program:   ORFEO Toolbox
Language:  C++
Date:      $Date$
Version:   $Revision$


Copyright (c) Centre National d'Etudes Spatiales. All rights reserved.
See OTBCopyright.txt for details.


This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __otbImageRegionTileMapSplitter_txx
#define __otbImageRegionTileMapSplitter_txx

#include "otbImageRegionTileMapSplitter.h"
#include "otbMath.h"

namespace otb
{

/**
   *
 */
template <unsigned int VImageDimension>
unsigned int
ImageRegionTileMapSplitter<VImageDimension>
::GetNumberOfSplits(const RegionType &region, unsigned int requestedNumber)
{
  int splitAxis;
  const SizeType &regionSize = region.GetSize();

  // split on the outermost dimension available
  splitAxis = VImageDimension - 1;
  while (regionSize[splitAxis] == 1)
  {
    --splitAxis;
    if (splitAxis < 0)
    { // cannot split
      itkDebugMacro("  Cannot Split");
      return 1;
    }
  }

  // determine the actual number of pieces that will be generated
  SizeValueType range = regionSize[splitAxis];
  int valuesPerPiece = static_cast<int>(vcl_ceil(static_cast<double>(range/((double)requestedNumber*256)) ) ) * 256;
  int maxPieceUsed = static_cast<int>(vcl_ceil(static_cast<double>(range/(double)valuesPerPiece)));

  return maxPieceUsed + 1;
}


/**
   *
 */
template <unsigned int VImageDimension>
itk::ImageRegion<VImageDimension>
ImageRegionTileMapSplitter<VImageDimension>
::GetSplit(unsigned int i, unsigned int numberOfPieces, const RegionType &region)
{
  int splitAxis;
  RegionType splitRegion;
  IndexType splitIndex;
  SizeType splitSize, regionSize;

  // Initialize the splitRegion to the requested region
  splitRegion = region;
  splitIndex = splitRegion.GetIndex();
  splitSize = splitRegion.GetSize();

  regionSize = region.GetSize();

  // split on the outermost dimension available
  splitAxis = VImageDimension - 1;
  while (regionSize[splitAxis] == 1)
  {
    --splitAxis;
    if (splitAxis < 0)
    { // cannot split
      itkDebugMacro("  Cannot Split");
      return splitRegion;
    }
  }

  // determine the actual number of pieces that will be generated
  SizeValueType range = regionSize[splitAxis];
  int valuesPerPiece = static_cast<int>((int)vcl_ceil(static_cast<double>(range/((double)numberOfPieces*256)))) * 256;
  int maxPieceUsed = static_cast<int>(vcl_ceil(static_cast<double>(range/(double)valuesPerPiece)));

  // Split the region
  if ((int) i == maxPieceUsed-1)
  {
    splitIndex[splitAxis] += i*valuesPerPiece;
    // last piece needs to process the "rest" dimension being split
//     splitSize[splitAxis] = splitSize[splitAxis] - i*valuesPerPiece;
    splitSize[splitAxis] = regionSize[splitAxis] - splitIndex[splitAxis];
  }
  if (((int) i == 0) && ((int) i != maxPieceUsed-1))
  {
    //First piece may not contain a whole piece
    //splitIndex stay at splitRegion.GetIndex();
    splitSize[splitAxis] = ((static_cast<int>(vcl_floor(static_cast<double>(splitIndex[splitAxis]/valuesPerPiece))))+1)
                           *valuesPerPiece - splitIndex[splitAxis];
  }
  if ((int) i < maxPieceUsed-1)
  {
    splitIndex[splitAxis] += i*valuesPerPiece;
    splitSize[splitAxis] = valuesPerPiece;
  }


  // set the split region ivars
  splitRegion.SetIndex( splitIndex );
  splitRegion.SetSize( splitSize );


  itkDebugMacro("  Split Piece: " << splitRegion );

  return splitRegion;
}



/**
       *
 */
template <unsigned int VImageDimension>
void
ImageRegionTileMapSplitter<VImageDimension>
::PrintSelf(std::ostream& os, itk::Indent indent) const
{
  Superclass::PrintSelf(os,indent);
}


} // end namespace itk

#endif