text: /*=========================================================================
   *
   *  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 __itkInterpolateImageFunction_h
  #define __itkInterpolateImageFunction_h
  
  #include "itkImageFunction.h"
  
  namespace itk
  {
  /** \class InterpolateImageFunction
   * \brief Base class for all image interpolaters.
   *
   * InterpolateImageFunction is the base for all ImageFunctions that
   * interpolates image intensity at a non-integer pixel position.
   * This class is templated over the input image type and the
   * coordinate representation type (e.g. float or double ).
   *
   * \warning This hierarchy of functions work only for images
   * with scalar pixel types. For images of vector pixel types
   * use VectorInterpolateImageFunctions.
   *
   * \sa VectorInterpolateImageFunction
   * \ingroup ImageFunctions ImageInterpolators
   *
   *
   * \ingroup ITKImageFunction
   */
  template< typename TInputImage, typename TCoordRep = double >
  class InterpolateImageFunction:
    public ImageFunction< TInputImage,
                          typename NumericTraits< typename TInputImage::PixelType >::RealType, TCoordRep >
  {
  public:
    /** Standard class typedefs. */
    typedef InterpolateImageFunction Self;
    typedef ImageFunction< TInputImage,
                           typename NumericTraits< typename TInputImage::PixelType >::RealType,
                           TCoordRep >                         Superclass;
  
    typedef SmartPointer< Self >       Pointer;
    typedef SmartPointer< const Self > ConstPointer;
  
    /** Run-time type information (and related methods). */
    itkTypeMacro(InterpolateImageFunction, ImageFunction);
  
    /** OutputType typedef support. */
    typedef typename Superclass::OutputType OutputType;
  
    /** InputImageType typedef support. */
    typedef typename Superclass::InputImageType InputImageType;
  
    /** Dimension underlying input image. */
    itkStaticConstMacro(ImageDimension, unsigned int,
                        Superclass::ImageDimension);
  
    /** Point typedef support. */
    typedef typename Superclass::PointType PointType;
  
    /** Index typedef support. */
    typedef typename Superclass::IndexType      IndexType;
    typedef typename Superclass::IndexValueType IndexValueType;
  
    /** ContinuousIndex typedef support. */
    typedef typename Superclass::ContinuousIndexType ContinuousIndexType;
  
    /** RealType typedef support. */
    typedef typename NumericTraits< typename TInputImage::PixelType >::RealType RealType;
  
    /** Interpolate the image at a point position
     *
     * Returns the interpolated image intensity at a
     * specified point position. No bounds checking is done.
     * The point is assume to lie within the image buffer.
     *
     * ImageFunction::IsInsideBuffer() can be used to check bounds before
     * calling the method. */
    virtual OutputType Evaluate(const PointType & point) const
    {
      ContinuousIndexType index;
  
      this->GetInputImage()->TransformPhysicalPointToContinuousIndex(point, index);
      return ( this->EvaluateAtContinuousIndex(index) );
    }
  
    /** Interpolate the image at a continuous index position
     *
     * Returns the interpolated image intensity at a
     * specified index position. No bounds checking is done.
     * The point is assume to lie within the image buffer.
     *
     * Subclasses must override this method.
     *
     * ImageFunction::IsInsideBuffer() can be used to check bounds before
     * calling the method. */
    virtual OutputType EvaluateAtContinuousIndex(
      const ContinuousIndexType & index) const = 0;
  
    /** Interpolate the image at an index position.
     *
     * Simply returns the image value at the
     * specified index position. No bounds checking is done.
     * The point is assume to lie within the image buffer.
     *
     * ImageFunction::IsInsideBuffer() can be used to check bounds before
     * calling the method. */
    virtual OutputType EvaluateAtIndex(const IndexType & index) const
    {
      return ( static_cast< RealType >( this->GetInputImage()->GetPixel(index) ) );
    }
  
  protected:
    InterpolateImageFunction(){}
    ~InterpolateImageFunction(){}
    void PrintSelf(std::ostream & os, Indent indent) const
    { Superclass::PrintSelf(os, indent); }
  
  private:
    InterpolateImageFunction(const Self &); //purposely not implemented
    void operator=(const Self &);           //purposely not implemented
  };
  } // end namespace itk
  
  #endif
  