Examples/Statistics/PointSetToAdaptor.cxx

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// Software Guide : BeginLatex
//
// We will describe how to use \doxygen{PointSet} as a \code{Sample}
// using an adaptor in this example.
//
// \index{itk::Sample!PointSetToListSampleAdaptor}
//
// \subdoxygen{Statistics}{PointSetToListSampleAdaptor} class requires the
// type of input \doxygen{PointSet} object. The \doxygen{PointSet} class is an
// associative data container. Each point in a \code{PointSet} object can have
// its associated data value (optional). For the statistics subsystem, current
// implementation of \code{PointSetToListSampleAdaptor} takes only the point
// part into consideration. In other words, the measurement vectors from a
// \code{PointSetToListSampleAdaptor} object are points from the
// \code{PointSet} object that is plugged-into the adaptor object.
//
// To use, an \doxygen{PointSetToListSampleAdaptor} object, we include the
// header file for the class.
//
// Software Guide : EndLatex
 
 
// Software Guide : BeginCodeSnippet
#include "itkPointSetToListSampleAdaptor.h"
// Software Guide : EndCodeSnippet
 
// Software Guide : BeginLatex
//
// Since, we are using an adaptor, we also include the header file for
// the \doxygen{PointSet} class.
//
// Software Guide :EndLatex
 
// Software Guide : BeginCodeSnippet
#include "itkPointSet.h"
// Software Guide : EndCodeSnippet
 
int
main()
{
  // Software Guide : BeginLatex
  //
  // We assume you already know how to create an \doxygen{PointSet} object.
  // The following code snippet will create a 2D image of float pixels filled
  // with random values.
  //
  // Software Guide :EndLatex
 
  // Software Guide : BeginCodeSnippet
  using FloatPointSet2DType = itk::PointSet<float, 2>;
 
  auto random = itk::RandomPointSetSource<FloatPointSet2DType>::New();
  random->SetMin(0.0);
  random->SetMax(1000.0);
 
  unsigned long size[2] = { 20, 20 };
  random->SetSize(size);
  float spacing[2] = { 0.7, 2.1 };
  random->SetSpacing(spacing);
  float origin[2] = { 15, 400 };
  random->SetOrigin(origin);
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // We now have an \doxygen{PointSet} object and need to cast it to an
  // \doxygen{PointSet} object with array type (anything derived from
  // the \doxygen{FixedArray} class) pixels.
  //
  // Since, the \doxygen{PointSet} object's pixel type is \code{float},
  // We will use single element \code{float} \doxygen{FixedArray}
  // as our measurement vector type. And that will also be our pixel
  // type for the cast filter.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using MeasurementVectorType = itk::FixedArray<float, 1>;
  using ArrayPointSetType = itk::PointSet<MeasurementVectorType, 2>;
  using CasterType = itk::ScalarToArrayCastPointSetFilter<FloatPointSet2DType,
                                                          ArrayPointSetType>;
 
  auto caster = CasterType::New();
  caster->SetInput(random->GetOutput());
  caster->Update();
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // Up to now, we spend most of time to prepare an \doxygen{PointSet} object
  // suitable for the adaptor. Actually, the hard part of this example is
  // done. Now, we must define an adaptor with the image type and
  // instantiate an object.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  using SampleType =
    itk::Statistics::PointSetToListSampleAdaptor<ArrayPointSetType>;
  auto sample = SampleType::New();
  // Software Guide : EndCodeSnippet
 
  // Software Guide : BeginLatex
  //
  // The final thing we have to is to plug-in the image object to the adaptor.
  // After that, we can use the common methods and iterator interfaces
  // shown in \ref{sec:SampleInterface}.
  //
  // Software Guide : EndLatex
 
  // Software Guide : BeginCodeSnippet
  sample->SetPointSet(caster->GetOutput());
  // Software Guide : EndCodeSnippet
 
  return EXIT_SUCCESS;
}