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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkBSplineResampleImageFilterBase.h,v $
  Language:  C++
  Date:      $Date: 2003/09/10 14:28:44 $
  Version:   $Revision: 1.5 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

  Portions of this code are covered under the VTK copyright.
  See VTKCopyright.txt or http://www.kitware.com/VTKCopyright.htm 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 __itkBSplineResampleImageFilterBase_h
#define __itkBSplineResampleImageFilterBase_h

#include <vector>

#include "itkImageLinearIteratorWithIndex.h"
#include "itkImageLinearConstIteratorWithIndex.h"
#include "itkImageRegionIterator.h"   // Used for the output iterator needs to match filter program
#include "itkProgressReporter.h"
#include "itkImageToImageFilter.h"

namespace itk
{
/** \class BSplineResampleImageFilterBase
 *  \brief Uses the "l2" spline pyramid implementation of B-Spline Filters to 
 *        up/down sample an image by a factor of 2.
 *
 * This class defines N-Dimension B-Spline transformation.
 * It is based on: 
 *    [1] M. Unser,
 *       "Splines: A Perfect Fit for Signal and Image Processing,"
 *        IEEE Signal Processing Magazine, vol. 16, no. 6, pp. 22-38,
 *        November 1999.
 *    [2] M. Unser, A. Aldroubi and M. Eden,
 *        "B-Spline Signal Processing: Part I--Theory,"
 *        IEEE Transactions on Signal Processing, vol. 41, no. 2, pp. 821-832,
 *        February 1993.
 *    [3] M. Unser, A. Aldroubi and M. Eden,
 *        "B-Spline Signal Processing: Part II--Efficient Design and Applications,"
 *        IEEE Transactions on Signal Processing, vol. 41, no. 2, pp. 834-848,
 *        February 1993.
 * And code obtained from bigwww.epfl.ch by Philippe Thevenaz
 * 
 * Limitations:  Spline order for the l2 pyramid must be between 0 and 3.
 *               This code cannot be multi-threaded since the entire image must be
 *                      traversed in the proper order.
 *               This code cannot be streamed and requires the all of the input image.
 *               Only up/down samples by a factor of 2.
 *               This is a base class and is not meant to be instantiated on its own.
 *                    It requires one of the itkBSplineDownsampleImageFilter or
 *                    itkBSplineUpsampleImageFilter classes.
 *
 * \sa itkBSplineDownsampleImageFilter
 * \sa itkBSplineUpsampleImageFilter
 * \sa itkBSplineCenteredL2ResampleImageFilterBase
 * \sa itkBSplineCenteredResampleImageFilterBase
 * \sa itkBSplineL2ResampleImageFilterBase
 *
 * \ingroup GeometricTransformationFilters
 * \ingroup SingleThreaded
 * \ingroup CannotBeStreamed
 */
template <class TInputImage, class TOutputImage>
class ITK_EXPORT BSplineResampleImageFilterBase : 
    public ImageToImageFilter<TInputImage,TOutputImage>  
{

public:
  /** Standard class typedefs. */
  typedef BSplineResampleImageFilterBase       Self;
  typedef ImageToImageFilter<TInputImage,TOutputImage>  Superclass;
  typedef SmartPointer<Self>                    Pointer;
  typedef SmartPointer<const Self>              ConstPointer;

  /** Run-time type information (and related methods). */
  itkTypeMacro(BSplineResampleImageFilterBase, ImageToImageFilter);

 
  /** New macro for creation of through a Smart Pointer */
  //  Must be sustantiated through another class. itkNewMacro( Self );

  /** InputInputImage typedef support. */
  typedef typename Superclass::InputImageType InputImageType;

  /** Dimension underlying input image. */
  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage::ImageDimension);

  /** Index typedef support. */
  typedef typename TInputImage::IndexType IndexType;

  /** Size typedef support. */
  typedef typename TInputImage::SizeType SizeType;

  /** Size typedef support. */
  typedef typename TInputImage::RegionType RegionType;

  /** OutputImagePixelType typedef support. */
  typedef typename Superclass::OutputImagePixelType OutputImagePixelType;

  /** Iterator typedef support */
  typedef itk::ImageLinearConstIteratorWithIndex<TInputImage> ConstInputImageIterator;

  /** Iterator typedef support */
  typedef itk::ImageLinearConstIteratorWithIndex<TOutputImage> ConstOutputImageIterator;

  /** Output Iterator typedef support */
  typedef itk::ImageLinearIteratorWithIndex<TOutputImage> OutputImageIterator;

  /** Set the spline order for interpolation.  Value must be between 0 and 3 with a 
   * default of 0. */
  void SetSplineOrder(int SplineOrder);

  /** Get the spline order */
  itkGetMacro(SplineOrder, int);


protected:
  /** Reduces an N-dimension image by a factor of 2 in each dimension. */
  void ReduceNDImage(OutputImageIterator &OutItr);

  /** Expands an N-dimension image by a factor of 2 in each dimension. */
  void ExpandNDImage(OutputImageIterator &OutItr);

  /** Initializes the pyramid spline coefficients.  Called when Spline order
   *   has been set. */
  virtual void InitializePyramidSplineFilter(int SplineOrder);

  /** The basic operator for reducing a line of data by a factor of 2 */
  virtual void Reduce1DImage( 
    const std::vector<double> & In, 
    OutputImageIterator & Iter, 
    unsigned int traverseSize,
    ProgressReporter &progress
    );

  /** The basic operator for expanding a line of data by a factor of 2 */
  virtual void Expand1DImage( 
    const std::vector<double> & In, 
    OutputImageIterator & Iter, 
    unsigned int traverseSize,
    ProgressReporter &progress
    );

  BSplineResampleImageFilterBase();
  virtual ~BSplineResampleImageFilterBase() {};
  void PrintSelf(std::ostream& os, Indent indent) const;

  int                       m_SplineOrder;// User specified spline order 
  int                       m_gSize;      // downsampling filter size
  int                       m_hSize;      // upsampling filter size
  std::vector<double>       m_g;          // downsampling filter coefficients
  std::vector<double>       m_h;          // upsampling filter coefficients

private:

  // Resizes m_Scratch Variable based on image sizes
  void InitializeScratch(SizeType DataLength);

  // Copies a line of data from the input to the m_Scratch for subsequent processing
  void CopyInputLineToScratch(ConstInputImageIterator & Iter);
  void CopyOutputLineToScratch(ConstOutputImageIterator & Iter);
  void CopyLineToScratch(ConstInputImageIterator & Iter);


  std::vector<double>       m_Scratch;        // temp storage for processing of Coefficients

  BSplineResampleImageFilterBase( const Self& ); //purposely not implemented
  void operator=( const Self& ); //purposely not implemented
  
};

} // namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkBSplineResampleImageFilterBase.txx"
#endif

#endif
