/*=========================================================================
 *
 *  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 itkEigenAnalysis2DImageFilter_h
#define itkEigenAnalysis2DImageFilter_h

#include "itkImageToImageFilter.h"

namespace itk
{
/** \class EigenAnalysis2DImageFilter
 * \brief Computes pixel-wise the eigen values and eigen vectors
 *        of a 2D symmetrical matrix.
 *
 * The filter expects three inputs images { A, B, C } representing
 * the component of the matrix
 *
 *                    | A  B |
 *                    | B  c |
 *
 * The eigen values are stored in two output images, and the eigen
 * vector associated with the maximum eigenvalue is stored in an
 * image using vector as pixel type.
 *
 * \ingroup ShouldBeThreaded IntensityImageFilters
 * \ingroup ITKEigen
 */

template< typename TInputImage, typename TEigenValueImage, typename TEigenVectorImage >
class EigenAnalysis2DImageFilter:
  public ImageToImageFilter< TInputImage, TEigenValueImage >
{
public:
  /** Standard class typedefs. */
  typedef EigenAnalysis2DImageFilter                          Self;
  typedef ImageToImageFilter< TInputImage, TEigenValueImage > Superclass;
  typedef SmartPointer< Self >                                Pointer;
  typedef SmartPointer< const Self >                          ConstPointer;

  /** Run-time type information (and related methods).   */
  itkTypeMacro(EigenAnalysis2DImageFilter, ImageToImageFilter);

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

  /** Typedef for the vector type representing the eigen vectors */
  typedef typename TEigenVectorImage::PixelType EigenVectorType;
  typedef typename EigenVectorType::ValueType   VectorComponentType;

  /** Superclass typedefs. */
  typedef typename Superclass::OutputImageRegionType OutputImageRegionType;

  /** Some convenient typedefs. */
  typedef TEigenValueImage                          EigenValueImageType;
  typedef typename EigenValueImageType::Pointer     EigenValueImagePointer;
  typedef typename EigenValueImageType::RegionType  EigenValueImageRegionType;
  typedef typename EigenValueImageType::PixelType   EigenValueImagePixelType;
  typedef TEigenVectorImage                         EigenVectorImageType;
  typedef typename EigenVectorImageType::Pointer    EigenVectorImagePointer;
  typedef typename EigenVectorImageType::RegionType EigenVectorImageRegionType;
  typedef typename EigenVectorImageType::PixelType  EigenVectorImagePixelType;

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

  /** Connect the image containting the elements [0,0]
   * of the input 2D matrix */
  void SetInput1(TInputImage *image1);

  /** Connect the image containting the elements [0,1]
   * of the input 2D matrix. This is the same [1,0]
   * element given that the input matrix is expected
   * to be symmetric */
  void SetInput2(TInputImage *image2);

  /** Connect the image containting the elements [1,1]
   * of the input 2D matrix */
  void SetInput3(TInputImage *image3);

  /** Get the Output image with the greatest eigenvalue */
  EigenValueImageType * GetMaxEigenValue();

  /** Get the Output image with the smallest eigenvalue */
  EigenValueImageType * GetMinEigenValue();

  /** Get the Output image with the eigen vector associated with
   * the greatest eigen value */
  EigenVectorImageType * GetMaxEigenVector();

  /**  Create the Output */
  typedef ProcessObject::DataObjectPointerArraySizeType DataObjectPointerArraySizeType;
  using Superclass::MakeOutput;
  DataObject::Pointer MakeOutput(DataObjectPointerArraySizeType idx) ITK_OVERRIDE;

#ifdef ITK_USE_CONCEPT_CHECKING
  // Begin concept checking
  itkConceptMacro( VectorComponentHasNumericTraitsCheck,
                   ( Concept::HasNumericTraits< VectorComponentType > ) );
  // End concept checking
#endif

protected:
  EigenAnalysis2DImageFilter();
  virtual ~EigenAnalysis2DImageFilter() {}

  void GenerateData(void) ITK_OVERRIDE;

private:
  EigenAnalysis2DImageFilter(const Self &) ITK_DELETE_FUNCTION;
  void operator=(const Self &) ITK_DELETE_FUNCTION;
};
} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkEigenAnalysis2DImageFilter.hxx"
#endif

#endif
