/*
 * Copyright (C) 2005-2020 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * 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
 *
 * 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 otbAffineFunctor_h
#define otbAffineFunctor_h

namespace otb
{
namespace Functor
{
/** \class AffineFunctor
 *  \brief This functor performs a linear transform of its input.
 *
 *  \f[ output = a*input + b \f]
 *
 * Coefficient a is a scalar, its type is templated (default is double).
 * Coefficient b has the same type as output type. Standard casting is applied
 * between input and output type.
 *
 * TInput and TOutput type are supposed to be scalar types.
 *
 * \ingroup OTBImageManipulation
 */
template <class TInput, class TOutput, class TScale = double>
class AffineFunctor
{
public:
  /// Constructor
  AffineFunctor() : m_A(0.), m_B(0.)
  {
  }

  /// Constructor
  virtual ~AffineFunctor()
  {
  }

  /// Accessors
  void SetA(TScale value)
  {
    m_A = value;
  }
  TScale GetA()
  {
    return m_A;
  }
  void SetB(TOutput value)
  {
    m_B = value;
  }
  TOutput GetB()
  {
    return m_B;
  }

  bool operator!=(const AffineFunctor& other) const
  {
    return ((m_A != other.GetA()) || (m_B != other.GetB()));
  }

  bool operator==(const AffineFunctor& other) const
  {
    return ((m_A == other.GetA()) && (m_B == other.GetB()));
  }

  // main computation method
  inline TOutput operator()(const TInput& x) const
  {
    return (m_B + static_cast<TOutput>(m_A * x));
  }

private:
  TScale  m_A;
  TOutput m_B;
};
} // End namespace Functor
} // End namespace otb

#endif
