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 itkScalarToRGBPixelFunctor_hxx
  #define itkScalarToRGBPixelFunctor_hxx
  
  #include "itkByteSwapper.h"
  
  namespace itk
  {
  namespace Functor
  {
  template <typename TScalar>
  ScalarToRGBPixelFunctor<TScalar>::ScalarToRGBPixelFunctor()
  {
    m_ColorIndex[0] = 0;
    m_ColorIndex[1] = 0;
    m_ColorIndex[2] = 0;
    const auto scalarSize = static_cast<unsigned int>(sizeof(ScalarType));
    for (unsigned int i = 0; i < scalarSize && i < 3; ++i)
    {
      m_ColorIndex[i] = i;
    }
  
  #ifdef ITK_WORDS_BIGENDIAN
    m_UseMSBForHashing = true;
  #else
    m_UseMSBForHashing = false;
  #endif
  }
  
  template <typename TScalar>
  auto
  ScalarToRGBPixelFunctor<TScalar>::operator()(const TScalar & v) const -> RGBPixelType
  {
    TScalar      buf = v;
    const auto * bytes = reinterpret_cast<const unsigned char *>(&buf);
  
    if (this->m_UseMSBForHashing == true)
    { // swap bytes
      // always swap regardless of system endianness
      if (ByteSwapper<TScalar>::SystemIsBigEndian())
      {
        ByteSwapper<TScalar>::SwapFromSystemToLittleEndian(&buf);
      }
      else
      {
        ByteSwapper<TScalar>::SwapFromSystemToBigEndian(&buf);
      }
    }
  
    RGBPixelType ans;
  
    ans[0] = static_cast<RGBComponentType>(bytes[m_ColorIndex[0]] * 3);
    ans[1] = static_cast<RGBComponentType>((bytes[m_ColorIndex[0]] + bytes[m_ColorIndex[1]]) * 5);
    ans[2] = static_cast<RGBComponentType>((bytes[m_ColorIndex[0]] + bytes[m_ColorIndex[2]]));
  
    return ans;
  }
  } // end namespace Functor
  } // end namespace itk
  
  #endif
  