{

// Software Guide : BeginLatex

//

// We first create a simple 2D image of size 10 by 10 pixels.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

using Image = itk::Image<short, 2>;

auto image = Image::New();

constexpr Image::SizeType size = { { 10, 10 } };

Image::RegionType region;

region.SetSize(size);

image->SetRegions(region);

image->Allocate();

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// Next we fill the image with increasing values.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

using Iterator = itk::ImageRegionIterator<Image>;

Iterator it(image, region);

short pixelValue = 0;

for (it.GoToBegin(); !it.IsAtEnd(); ++it, ++pixelValue)

{

it.Set(pixelValue);

}

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// We can now define the \code{ImageSpatialObject} which is templated over

// the dimension and the pixel type of the image.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

using ImageSpatialObject = itk::ImageSpatialObject<2, short>;

auto imageSO = ImageSpatialObject::New();

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// Then we set the itkImage to the \code{ImageSpatialObject} by using the

// \code{SetImage()} function.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

imageSO->SetImage(image);

imageSO->Update();

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// At this point we can use \code{IsInsideInWorldSpace()},

// \code{IsInsideInObjectSpace()}, \code{ValueAtInWorldSpace()},

// \code{ValueAtInObjectSpace()}, \code{DerivativeAtInWorldSpace()},

// and \code{DerivativeAtInObjectSpace()} functions inherent in

// SpatialObjects. The \code{IsInsideInWorldSpace()} value can be

// particularly useful when dealing with registration.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

using Point = itk::Point<double, 2>;

auto insidePoint = itk::MakeFilled<Point>(9);

if (imageSO->IsInsideInWorldSpace(insidePoint))

{

std::cout << insidePoint << " is inside the image." << std::endl;

}

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// The \code{ValueAtInWorldSpace()} returns the value of the closest pixel,

// i.e no interpolation, to a given physical point.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

double returnedValue;

imageSO->ValueAtInWorldSpace(insidePoint, returnedValue);

std::cout << "ValueAt(" << insidePoint << ") = " << returnedValue

<< std::endl;

// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex

//

// The derivative at a specified position in space can be computed using

// the \code{DerivativeAtInWorldSpace()} function. The first argument is

// the point in physical coordinates where we are evaluating the

// derivatives. The second argument is the order of the derivation, and the

// third argument is the result expressed as a \itkref{Vector}.

// Derivatives are computed iteratively using finite differences and, like

// the \code{ValueAtInWorldSpace()}, no interpolator is used.

//

// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet

ImageSpatialObject::DerivativeVectorType returnedDerivative;

imageSO->DerivativeAtInWorldSpace(insidePoint, 1, returnedDerivative);

std::cout << "First derivative at " << insidePoint;

std::cout << " = " << returnedDerivative << std::endl;

// Software Guide : EndCodeSnippet

return EXIT_SUCCESS;