Examples/DataRepresentation/Path/PolyLineParametricPath1.cxx

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// Software Guide : BeginLatex
//
// This example illustrates how to use the \doxygen{PolyLineParametricPath}.
// This class will typically be used for representing in a concise way the
// output of an image segmentation algorithm in 2D.  The
// \code{PolyLineParametricPath} however could also be used for representing
// any open or close curve in N-Dimensions as a linear piece-wise approximation.
//
//
// First, the header file of the \code{PolyLineParametricPath} class must be included.
//
// Software Guide : EndLatex


#include "itkImage.h"
#include "itkImageFileReader.h"

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

int main(int argc, char * argv [] )
{

  if( argc < 2 )
    {
    std::cerr << "Missing arguments" << std::endl;
    std::cerr << "Usage: PolyLineParametricPath  inputImageFileName" << std::endl;
    return EXIT_FAILURE;
    }

  // Software Guide : BeginLatex
  //
  // The path is instantiated over the dimension of the image.
  // In this example the image and path are two-dimensional.
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  constexpr unsigned int Dimension = 2;

  using ImageType = itk::Image< unsigned char, Dimension >;

  using PathType = itk::PolyLineParametricPath< Dimension >;
  // Software Guide : EndCodeSnippet


  using ReaderType = itk::ImageFileReader< ImageType >;

  ReaderType::Pointer   reader = ReaderType::New();

  reader->SetFileName( argv[1] );

  try
    {
    reader->Update();
    }
  catch( itk::ExceptionObject & excp )
    {
    std::cout << "Problem reading the input image " << std::endl;
    std::cout << excp << std::endl;
    return EXIT_FAILURE;
    }

  // Software Guide : BeginCodeSnippet
  ImageType::ConstPointer image = reader->GetOutput();
  PathType::Pointer path = PathType::New();
  path->Initialize();

  using ContinuousIndexType = PathType::ContinuousIndexType;
  ContinuousIndexType cindex;

  using ImagePointType = ImageType::PointType;
  ImagePointType origin = image->GetOrigin();

  ImageType::SpacingType spacing = image->GetSpacing();
  ImageType::SizeType    size    = image->GetBufferedRegion().GetSize();

  ImagePointType point;

  point[0] = origin[0] + spacing[0] * size[0];
  point[1] = origin[1] + spacing[1] * size[1];

  image->TransformPhysicalPointToContinuousIndex( origin, cindex );
  path->AddVertex( cindex );
  image->TransformPhysicalPointToContinuousIndex( point, cindex );
  path->AddVertex( cindex );
  // Software Guide : EndCodeSnippet

  return EXIT_SUCCESS;
}