/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef __itkChainCodeToFourierSeriesPathFilter_h
#define __itkChainCodeToFourierSeriesPathFilter_h

#include "itkPathToPathFilter.h"
#include "itkOffset.h"
//Templates require interfaces conforming to itkPath.h and itkChainCodePath.h

namespace itk
{
/** \class ChainCodeToFourierSeriesPathFilter
 * \brief Filter that produces a Fourier series version of a chain code path
 *
 * ChainCodeToFourierSeriesPathFilter produces a Fourier series representation
 * of a chain code path. By default, the first 8 harmonics (frequency
 * coefficients, which include the "DC" term) are computed.
 * SetNumberOfHarmonics() can be used to override this value.
 * Because the requested number of harmonics may not be able to be computed,
 * it is advisable to check the number of harmonics in the actual output.
 *
 * \ingroup PathFilters
 * \ingroup ITKPath
 */
template< typename TInputChainCodePath, typename TOutputFourierSeriesPath >
class ChainCodeToFourierSeriesPathFilter:public
  PathToPathFilter< TInputChainCodePath, TOutputFourierSeriesPath >
{
public:
  /** Standard class typedefs. */
  typedef ChainCodeToFourierSeriesPathFilter Self;
  typedef PathToPathFilter< TInputChainCodePath,
                            TOutputFourierSeriesPath >  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(ChainCodeToFourierSeriesPathFilter, PathToPathFilter);

  /** Some convenient typedefs. */
  typedef TInputChainCodePath                 InputPathType;
  typedef typename InputPathType::Pointer     InputPathPointer;
  typedef typename InputPathType::InputType   InputPathInputType;
  typedef TOutputFourierSeriesPath            OutputPathType;
  typedef typename OutputPathType::Pointer    OutputPathPointer;
  typedef typename OutputPathType::InputType  OutputPathInputType;
  typedef typename InputPathType::IndexType   IndexType;
  typedef typename InputPathType::OffsetType  OffsetType;
  typedef typename OutputPathType::VectorType VectorType;

  /** Set the number of harmonics to try to compute.  By default, the first 8
   * harmonics (frequency coefficients, which include the "DC" term) are
   * computed.  SetNumberOfHarmonics() can be used to override this value.  If
   * the chain code has too few steps to calculate the desired number of
   * harmonics (due to the Nyquist criterion), then as many harmonics as are
   * possible (input->NumberOfSteps()/2) will be calculated, but at least 2
   * harmonics will always be calculated.*/
  itkSetMacro(NumberOfHarmonics, unsigned int)

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

  void GenerateData(void);

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

  unsigned int m_NumberOfHarmonics;
};
} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkChainCodeToFourierSeriesPathFilter.hxx"
#endif

#endif
