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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkExpandImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2006/03/27 17:01:09 $
  Version:   $Revision: 1.11 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.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 __itkExpandImageFilter_h
#define __itkExpandImageFilter_h

#include "itkImageToImageFilter.h"
#include "itkInterpolateImageFunction.h"
#include "itkLinearInterpolateImageFunction.h"

namespace itk
{

/** \class ExpandImageFilter
 * \brief Expand the size of an image by an integer factor in each
 * dimension.
 *
 * ExpandImageFilter increases the size of an image by an integer
 * factor in each dimension using a interpolation method.
 * The output image size in each dimension is given by:
 *
 * OutputSize[j] = InputSize[j] * ExpandFactors[j]
 *
 * The output values are obtained by interpolating the input image.
 * The default interpolation type used is the LinearInterpolateImageFunction.
 * The user can specify a particular interpolation function via
 * SetInterpolator(). Note that the input interpolator must derive
 * from base class InterpolateImageFunction.
 *
 * When the LargestPossibleRegion is requested, the output image will
 * contain padding at the upper edge of each dimension. The width
 * of padding in the i'th dimension is (ExpandFactors[i] - 1). Users can
 * specify the padding value used by setting the EdgePaddingValue.
 *
 * This filter will produce an output with different pixel spacing
 * that its input image such that:
 *
 * OutputSpacing[j] = InputSpacing[j] / ExpandFactors[j]
 *
 * The filter is templated over the input image type and the output 
 * image type.
 *
 * This filter is implemented as a multithreaded filter and supports
 * streaming.
 *
 * \warning This filter only works for image with scalar pixel types.
 * For vector images use VectorExpandImageFilter.
 *
 * This filter assumes that the input and output image has the same
 * number of dimensions.
 *
 * \sa InterpolateImageFunction
 * \sa LinearInterpolationImageFunction
 * \sa VectorExpandImageFilter
 *
 * \ingroup GeometricTransform
 */
template <
  class TInputImage, 
  class TOutputImage 
  >
class ITK_EXPORT ExpandImageFilter:
    public ImageToImageFilter<TInputImage,TOutputImage>
{
public:
  /** Standard class typedefs. */
  typedef ExpandImageFilter         Self;
  typedef ImageToImageFilter<TInputImage,TOutputImage>  Superclass;
  typedef SmartPointer<Self>  Pointer;
  typedef SmartPointer<const Self>  ConstPointer;

  /** Method for creation through the object factory. */
  itkNewMacro(Self);  

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

  /** Typedef to describe the output image region type. */
  typedef typename TOutputImage::RegionType OutputImageRegionType;

  /** ImageDimension enumeration. */
  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage::ImageDimension);

  /** Inherit some types from superclass. */
  typedef typename Superclass::InputImageType  InputImageType;
  typedef typename Superclass::OutputImageType OutputImageType;
  typedef typename OutputImageType::PixelType  OutputPixelType;
  typedef typename InputImageType::Pointer  InputImagePointer;
  typedef typename OutputImageType::Pointer  OutputImagePointer;

  /** Typedef support for the interpolation function. */
  typedef double CoordRepType;
  typedef InterpolateImageFunction<InputImageType,CoordRepType> 
  InterpolatorType;
  typedef typename InterpolatorType::Pointer InterpolatorPointer;
  typedef LinearInterpolateImageFunction<InputImageType,CoordRepType> 
  DefaultInterpolatorType;

  /** Set the interpolator function. */
  itkSetObjectMacro( Interpolator, InterpolatorType );

  /** Get a pointer to the interpolator function. */
  itkGetObjectMacro( Interpolator, InterpolatorType );

  /** Set the expand factors. Values are clamped to 
   * a minimum value of 1. Default is 1 for all dimensions. */
  virtual void SetExpandFactors( const unsigned int factors[] );
  virtual void SetExpandFactors( const unsigned int factor );

  /** Get the expand factors. */
  virtual const unsigned int * GetExpandFactors() const
  { return m_ExpandFactors; }

  /** Set the edge padding value. The default is zero. */
  itkSetMacro( EdgePaddingValue, OutputPixelType );

  /** Get the edge padding value */
  itkGetMacro( EdgePaddingValue, OutputPixelType );

  /** ExpandImageFilter produces an image which is a different resolution and
   * with a different pixel spacing than its input image.  As such,
   * ExpandImageFilter needs to provide an implementation for
   * UpdateOutputInformation() in order to inform the pipeline execution model.
   * The original documentation of this method is below.
   * \sa ProcessObject::GenerateOutputInformaton() */
  virtual void GenerateOutputInformation();

  /** ExpandImageFilter needs a smaller input requested region than the output
   * requested region.  As such, ShrinkImageFilter needs to provide an 
   * implementation for GenerateInputRequestedRegion() in order to inform 
   * the pipeline execution model.  
   * \sa ProcessObject::GenerateInputRequestedRegion() */
  virtual void GenerateInputRequestedRegion();

#ifdef ITK_USE_CONCEPT_CHECKING
  /** Begin concept checking */
  itkConceptMacro(InputHasNumericTraitsCheck,
    (Concept::HasNumericTraits<typename TInputImage::PixelType>));
  itkConceptMacro(OutputHasNumericTraitsCheck,
    (Concept::HasNumericTraits<OutputPixelType>));
  /** End concept checking */
#endif

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

  /** ExpandImageFilter is implemented as a multithreaded filter.  Therefore,
   * this implementation provides a ThreadedGenerateData() routine which
   * is called for each processing thread. The output image data is allocated
   * automatically by the superclass prior to calling ThreadedGenerateData().
   * ThreadedGenerateData can only write to the portion of the output image
   * specified by the parameter "outputRegionForThread"
   *
   * \sa ImageToImageFilter::ThreadedGenerateData(),
   *     ImageToImageFilter::GenerateData() */
  virtual
  void ThreadedGenerateData(const OutputImageRegionType& outputRegionForThread,
                            int threadId );
  
  /** This method is used to set the state of the filter before 
   * multi-threading. */
  virtual void BeforeThreadedGenerateData();

private:
  ExpandImageFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

  unsigned int           m_ExpandFactors[ImageDimension];
  InterpolatorPointer    m_Interpolator;
  OutputPixelType        m_EdgePaddingValue;
 
};

} // end namespace itk

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

#endif
