Examples/DataRepresentation/Path/PolyLineParametricPath1.cxx

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 *  Copyright NumFOCUS
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 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
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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>;
 
  auto reader = ReaderType::New();
 
  reader->SetFileName(argv[1]);
 
  try
  {
    reader->Update();
  }
  catch (const 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();
  auto                    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];
 
  using ContinuousIndexValueType = ContinuousIndexType::ValueType;
 
  cindex =
    image->TransformPhysicalPointToContinuousIndex<ContinuousIndexValueType>(
      origin);
  path->AddVertex(cindex);
  cindex =
    image->TransformPhysicalPointToContinuousIndex<ContinuousIndexValueType>(
      point);
  path->AddVertex(cindex);
  // Software Guide : EndCodeSnippet
 
  return EXIT_SUCCESS;
}