text: /*
   * Copyright (C) 2005-2017 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.
   */
  
  
  
  // Software Guide : BeginLatex
  //
  //This example illustrates how the \doxygen{itk}{ImageAdaptor} can be used to cast
  // an image from one pixel type to another. In particular, we will
  // \emph{adapt} an \code{unsigned char} image to make it appear as an image of
  // pixel type \code{float}.
  //
  // \index{itk::ImageAdaptor!Instantiation}
  // \index{itk::ImageAdaptor!Header}
  //
  // We begin by including the relevant headers.
  //
  // Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
  #include "otbImage.h"
  #include "itkImageAdaptor.h"
  // Software Guide : EndCodeSnippet
  
  #include "itkImageRegionIteratorWithIndex.h"
  #include "otbImageFileReader.h"
  
  //  Software Guide : BeginLatex
  //
  // First, we need to define a \emph{pixel accessor} class that does the actual
  // conversion. Note that in general, the only valid operations for pixel
  // accessors are those that only require the value of the input pixel. As
  // such, neighborhood type operations are not possible. A pixel accessor must
  // provide methods \code{Set()} and \code{Get()}, and define the types of
  // \code{InternalPixelType} and \code{ExternalPixelType}. The
  // \code{InternalPixelType} corresponds to the pixel type of the image to be
  // adapted (\code{unsigned char} in this example). The \code{ExternalPixelType}
  // corresponds to the pixel type we wish to emulate with the ImageAdaptor
  // (\code{float} in this case).
  //
  //  Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
  class CastPixelAccessor
  {
  public:
    typedef unsigned char InternalType;
    typedef float         ExternalType;
  
    static void Set(InternalType& output, const ExternalType& input)
    {
      output = static_cast<InternalType>(input);
    }
  
    static ExternalType Get(const InternalType& input)
    {
      return static_cast<ExternalType>(input);
    }
  };
  // Software Guide : EndCodeSnippet
  
  //-------------------------
  //
  //   Main code
  //
  //-------------------------
  
  int main(int argc, char *argv[])
  {
    if (argc < 2)
      {
      std::cerr << "Usage: " << std::endl;
      std::cerr << "ImageAdaptor1   inputFileName" << std::endl;
      return -1;
      }
  
  //  Software Guide : BeginLatex
  //
  //  The CastPixelAccessor class simply applies a
  //  \code{static\_cast} to the pixel values. We now use this pixel accessor
  //  to define the image adaptor type and create an instance using
  //  the standard \code{New()} method.
  //
  //  Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
    typedef unsigned char InputPixelType;
    const unsigned int Dimension = 2;
    typedef otb::Image<InputPixelType, Dimension> ImageType;
  
    typedef itk::ImageAdaptor<ImageType, CastPixelAccessor> ImageAdaptorType;
    ImageAdaptorType::Pointer adaptor = ImageAdaptorType::New();
  // Software Guide : EndCodeSnippet
  
  // Software Guide : BeginLatex
  //
  // We also create an image reader templated over the input image type and
  // read the input image from file.
  //
  // Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
    typedef otb::ImageFileReader<ImageType> ReaderType;
    ReaderType::Pointer reader = ReaderType::New();
  // Software Guide : EndCodeSnippet
  
    reader->SetFileName(argv[1]);
    reader->Update();
  
  //  Software Guide : BeginLatex
  //
  //  The output of the reader is then connected as the input to the image
  //  adaptor.
  //
  //  Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
    adaptor->SetImage(reader->GetOutput());
  // Software Guide : EndCodeSnippet
  
  //  Software Guide : BeginLatex
  //
  //  In the following code, we visit the image using an iterator
  //  instantiated using the adapted image type and compute the
  //  sum of the pixel values.
  //
  //  Software Guide : EndLatex
  
  // Software Guide : BeginCodeSnippet
    typedef itk::ImageRegionIteratorWithIndex<ImageAdaptorType> IteratorType;
    IteratorType it(adaptor, adaptor->GetBufferedRegion());
  
    double sum = 0.0;
    it.GoToBegin();
    while (!it.IsAtEnd())
      {
      float value = it.Get();
      sum += value;
      ++it;
      }
  // Software Guide : EndCodeSnippet
  
    std::cout << "Sum of pixels is: " << sum << std::endl;
  
  //  Software Guide : BeginLatex
  //
  // Although in this example, we are just performing a simple summation, the key
  // concept is that access to pixels is performed as if the pixel is of type
  //  \code{float}. Additionally, it should be noted that the adaptor is used
  // as if it was an actual image and not as a filter. ImageAdaptors conform
  // to the same API as the  \doxygen{otb}{Image} class.
  //
  //  Software Guide : EndLatex
  
    return EXIT_SUCCESS;
  }
  