DataRepresentation/Image/RGBImage.cxx

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

  Program:   ORFEO Toolbox
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


  Copyright (c) Centre National d'Etudes Spatiales. All rights reserved.
  See OTBCopyright.txt for details.

  Some parts of this code are derived from ITK. See ITKCopyright.txt
  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.

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


#include "otbImage.h"
#include "otbImageFileReader.h"

//  Software Guide : BeginLatex
//
//  Thanks to the flexibility offered by the
//  \href{http://www.boost.org/more/generic_programming.html}{Generic
//  Programming} style on which OTB is based, it is possible to
//  instantiate images of arbitrary pixel type.  The following example
//  illustrates how a color image with RGB pixels can be defined.
//
//  A class intended to support the RGB pixel type is available in ITK.  You
//  could also define your own pixel class and use it to instantiate a
//  custom image type. In order to use the \doxygen{itk}{RGBPixel} class, it is
//  necessary to include its header file.
//
//  \index{itk::RGBPixel}
//  \index{itk::RGBPixel!Image}
//  \index{itk::RGBPixel!header}
//
//  Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
#include "itkRGBPixel.h"
// Software Guide : EndCodeSnippet

int main(int, char * argv[])
{
  // Software Guide : BeginLatex
  //
  // The RGB pixel class is templated over a type used to represent each one
  // of the red, green and blue pixel components. A typical instantiation of the
  // templated class is as follows.
  //
  //  \index{itk::RGBPixel!Instantiation}
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  typedef itk::RGBPixel<unsigned char> PixelType;
  // Software Guide : EndCodeSnippet

  // Software Guide : BeginLatex
  //
  // The type is then used as the pixel template parameter of the image.
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  typedef otb::Image<PixelType, 2> ImageType;
  // Software Guide : EndCodeSnippet

  // Software Guide : BeginLatex
  //
  // The image type can be used to instantiate other filter, for example,
  // an \doxygen{otb}{ImageFileReader} object that will read the image from a
  // file.
  //
  // \index{otb::ImageFileReader!RGB Image}
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  typedef otb::ImageFileReader<ImageType> ReaderType;
  // Software Guide : EndCodeSnippet

  ReaderType::Pointer reader = ReaderType::New();
  const char *        filename = argv[1];
  reader->SetFileName(filename);
  reader->Update();

  ImageType::Pointer image = reader->GetOutput();

  ImageType::IndexType pixelIndex;

  pixelIndex[0] = 25;
  pixelIndex[1] = 35;

  // Software Guide : BeginLatex
  //
  // Access to the color components of the pixels can now be performed using
  // the methods provided by the RGBPixel class.
  //
  // \index{otb::Image!GetPixel()}
  // \index{itk::RGBPixel!GetRed()}
  // \index{itk::RGBPixel!GetGreen()}
  // \index{itk::RGBPixel!GetBlue()}
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  PixelType onePixel = image->GetPixel(pixelIndex);

  PixelType::ValueType red   = onePixel.GetRed();
  PixelType::ValueType green = onePixel.GetGreen();
  PixelType::ValueType blue  = onePixel.GetBlue();
  // Software Guide : EndCodeSnippet

  std::cout << "Pixel values from GetRed, GetGreen, GetBlue:" << std::endl;
  std::cout << "Red = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(red)
            << std::endl;
  std::cout << "Green = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(green)
            << std::endl;
  std::cout << "Blue = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(blue)
            << std::endl;

  // Software Guide : BeginLatex
  //
  // The subindex notation can also be used since the \doxygen{itk}{RGBPixel} inherits the
  // \code{[]} operator from the \doxygen{itk}{FixedArray} class.
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  red   = onePixel[0];  // extract Red   component
  green = onePixel[1];  // extract Green component
  blue  = onePixel[2];  // extract Blue  component

  std::cout << "Pixel values:" << std::endl;
  std::cout << "Red = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(red)
            << std::endl;
  std::cout << "Green = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(green)
            << std::endl;
  std::cout << "Blue = "
            << itk::NumericTraits<PixelType::ValueType>::PrintType(blue)
            << std::endl;
  // Software Guide : EndCodeSnippet

  // Lets repeat that both \code{SetPixel()} and \code{GetPixel()} are
  // inefficient and should only be used for debugging purposes or for
  // implementing interactions with a graphical user interface such as
  // querying pixel value by clicking with the mouse.
  //

  return EXIT_SUCCESS;
}