itkCentralDifferenceImageFunction.h

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/*=========================================================================
 *
 *  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 itkCentralDifferenceImageFunction_h
#define itkCentralDifferenceImageFunction_h

#include "itkImageFunction.h"
#include "itkCovariantVector.h"
#include "itkInterpolateImageFunction.h"
#include "itkDefaultConvertPixelTraits.h"

namespace itk
{
template<
  typename TInputImage,
  typename TCoordRep = float,
  typename TOutputType = CovariantVector<double, TInputImage::ImageDimension >
  >
class ITK_TEMPLATE_EXPORT CentralDifferenceImageFunction:
  public ImageFunction< TInputImage,
                        TOutputType,
                        TCoordRep >
{
public:

  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage::ImageDimension);

  typedef CentralDifferenceImageFunction   Self;
  typedef ImageFunction< TInputImage,
                         TOutputType,
                         TCoordRep >       Superclass;
  typedef SmartPointer< Self >             Pointer;
  typedef SmartPointer< const Self >       ConstPointer;

  itkTypeMacro(CentralDifferenceImageFunction, ImageFunction);

  itkNewMacro(Self);

  typedef TInputImage InputImageType;

  typedef typename InputImageType::PixelType InputPixelType;

  typedef DefaultConvertPixelTraits< InputPixelType > InputPixelConvertType;

  typedef typename Superclass::OutputType OutputType;

  typedef DefaultConvertPixelTraits<OutputType> OutputConvertType;

  typedef typename OutputConvertType::ComponentType OutputValueType;

  typedef CovariantVector<OutputValueType, itkGetStaticConstMacro(ImageDimension) > ScalarDerivativeType;

  typedef typename Superclass::IndexType IndexType;

  typedef typename Superclass::ContinuousIndexType ContinuousIndexType;

  typedef typename Superclass::PointType PointType;

  typedef typename TInputImage::SpacingType SpacingType;

  typedef InterpolateImageFunction< TInputImage, TCoordRep > InterpolatorType;
  typedef typename InterpolatorType::Pointer                 InterpolatorPointer;

  virtual void SetInputImage(const TInputImage *inputData) ITK_OVERRIDE;

  virtual void SetInterpolator(InterpolatorType *interpolator);

  itkGetModifiableObjectMacro(Interpolator, InterpolatorType );

  virtual OutputType EvaluateAtIndex(const IndexType & index) const ITK_OVERRIDE;

  virtual OutputType Evaluate(const PointType & point) const ITK_OVERRIDE;

  virtual OutputType EvaluateAtContinuousIndex( const ContinuousIndexType & cindex) const ITK_OVERRIDE;

  itkSetMacro(UseImageDirection, bool);
  itkGetConstMacro(UseImageDirection, bool);
  itkBooleanMacro(UseImageDirection);

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

private:
  ITK_DISALLOW_COPY_AND_ASSIGN(CentralDifferenceImageFunction);


  template<typename T>
  struct OutputTypeSpecializationStructType
  {
    typedef T Type;
  };

  template< typename Type >
  inline void EvaluateAtIndexSpecialized( const IndexType & index, OutputType & derivative, OutputTypeSpecializationStructType<OutputType>) const;
  template< typename Type >
  inline void EvaluateAtIndexSpecialized( const IndexType & index, OutputType & derivative, OutputTypeSpecializationStructType<Type>) const;

  template< typename Type >
  inline void EvaluateAtContinuousIndexSpecialized( const ContinuousIndexType & index, OutputType & derivative, OutputTypeSpecializationStructType<OutputType>) const;
  template< typename Type >
  inline void EvaluateAtContinuousIndexSpecialized( const ContinuousIndexType & index, OutputType & derivative, OutputTypeSpecializationStructType<Type>) const;

  // NOTE: for some unknown reason, making these methods inline (as those above are inlined) makes them run *slower*.
  template< typename Type >
  void EvaluateSpecialized( const PointType & point, OutputType & derivative, OutputTypeSpecializationStructType<OutputType>) const;
  template< typename Type >
  void EvaluateSpecialized( const PointType & point, OutputType & derivative, OutputTypeSpecializationStructType<Type>) const;

  // flag to take or not the image direction into account
  // when computing the derivatives.
  bool m_UseImageDirection;

  // interpolator
  InterpolatorPointer   m_Interpolator;
};
} // end namespace itk

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

#endif