text: /*=========================================================================
   *
   *  Copyright NumFOCUS
   *
   *  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 itkRedPixelAccessor_h
  #define itkRedPixelAccessor_h
  
  #include "itkRGBPixel.h"
  
  namespace itk
  {
  /**
   *\class RedPixelAccessor
   * \brief Give access to the red component of a RGBPixel type.
   *
   * This class is intended to be used as parameter of
   * an ImageAdaptor to make an RGBPixel image appear as being
   * of scalar type T, showing only the Red component.
   *
   * \sa ImageAdaptor
   * \ingroup ImageAdaptors
   * \ingroup ITKImageAdaptors
   */
  
  template <typename T>
  class RedPixelAccessor
  {
  public:
    /** Standard class type aliases. */
    using Self = RedPixelAccessor;
  
    /** External type alias. It defines the external aspect
     * that this class will exhibit */
    using ExternalType = T;
  
    /** Internal type alias. It defines the internal real
     * representation of data */
    using InternalType = RGBPixel<T>;
  
    /** Write access to the Red component */
    inline void
    Set(InternalType & output, const ExternalType & input) const
    {
      output.SetRed(input);
    }
  
    /** Read access to the Red component */
    inline const ExternalType &
    Get(const InternalType & input) const
    {
      return input.GetRed();
    }
  
    bool
    operator==(const Self &) const
    {
      return true;
    }
  
    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(Self);
  };
  } // end namespace itk
  
  #endif
  