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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkScalarVector.h,v $
  Language:  C++
  Date:      $Date: 2003/09/10 14:29:25 $
  Version:   $Revision: 1.17 $

  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 __itkScalarVector_h
#define __itkScalarVector_h

#include "itkMacro.h"
#include "vnl/vnl_vector_fixed.h"

#include <memory>

namespace itk
{

/** \class ScalarVector
 * \brief A templated class holding bot scalar and vector values and
 *         responding to the GetScalar() and GetVector() methods.
 * 
 * ScalarVector is a templated class that holds a scalar value plus an
 * array of values (a vector).  ScalarVector can be used as the data type
 * held at each pixel in an Image or at each vertex of an Mesh. There
 * are three template parameters: the type of scalar, the type of vector, and
 * the number of components of the vector. The types can be any data type
 * that behaves like a primitive (or atomic) data type (int, short, float,
 * complex).  itk filters that rely on scalar data assume the data type held
 * at each pixel or each vertex responds to GetScalar()/SetScalar()
 * methods. itk filters that rely on vector data assume the data type held at
 * each pixel or each vertex responds to GetVector()/SetVector() methods. If
 * not, a compile time error will occur.
 *
 * ScalarVector is not a dynamically extendible array like std::vector. It
 * is intended to be used like a mathematical vector.
 *
 * If you wish a simpler pixel types, you can use Scalar, which represents
 * a single data value at a pixel. YOu can also use Vector, which supports
 * (for a given pixel) an array of vector values.
 * 
 * \sa Image
 * \sa Mesh
 * \sa Scalar
 * \sa Vector 
 * \ingroup DataRepresentation
 */
template<class TScalar, class TVector, unsigned int TVectorDimension=3>
class ITK_EXPORT ScalarVector
{
public:
  /** Standard class typedefs. */
  typedef ScalarVector  Self;
  
  /** ValueType can be used to declare a variable that is the same type
   * as the data held in the scalar portion of the ScalarVector.   */
  typedef TScalar ValueType;

  /** ValueType can be used to declare a variable that is the same type
   * as the data held in the scalar portion of the ScalarVector.   */
  typedef TScalar ScalarValueType;

  /** ValueType can be used to declare a variable that is the same type
   * as the data held in the scalar portion of the ScalarVector.   */
  typedef TVector VectorValueType;

  /** VectorType can be used to declare a variable that is the same type
   * as the internal vector.   */
  typedef vnl_vector_fixed<TVector, TVectorDimension> VectorType;

  /** Get the scalar value. \sa SetScalar() */
  TScalar GetScalar() const 
    { return m_Scalar; }

  /** Set the scalar value. \sa GetScalar() */
  void SetScalar(const TScalar &val) 
    { m_Scalar = val; }

  /** Get the dimension (size) of the vector. */
  static unsigned int GetVectorDimension() 
    { return TVectorDimension; }
  
  /** Get the vector. This provides a read only reference to the vector.
   * \sa SetVector(). */
  const VectorType &GetVector() const 
    { return m_Vector; }

  /** Get the vector. This provides a read/write reference to the vector.
   * \sa SetVector */
  VectorType &GetVector()  
    { return m_Vector; }

  /** Set the vector. \sa GetVector */
  void SetVector(const VectorType &vec)
    { m_Vector = vec; }

private:
  TScalar m_Scalar;
  VectorType m_Vector;
};

  
} // end namespace itk
  
#endif 
