ITK  5.3.0
Insight Toolkit
Examples/DataRepresentation/Image/Image3.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.
* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*=========================================================================*/
// Software Guide : BeginLatex
//
// This example illustrates the use of the \code{SetPixel()} and
// \code{GetPixel()} methods. These two methods provide direct access to the
// pixel data contained in the image. Note that these two methods are
// relatively slow and should not be used in situations where
// high-performance access is required. Image iterators are the appropriate
// mechanism to efficiently access image pixel data. (See
// Chapter~\ref{sec:ImageIteratorsChapter} on page
// \pageref{sec:ImageIteratorsChapter} for information about image
// iterators.)
//
// Software Guide : EndLatex
#include "itkImage.h"
int
main(int, char *[])
{
// First the image type should be declared
using ImageType = itk::Image<unsigned short, 3>;
// Then the image object can be created
ImageType::Pointer image = ImageType::New();
// The image region should be initialized
const ImageType::SizeType size = {
{ 200, 200, 200 }
}; // Size along {X,Y,Z}
const ImageType::IndexType start = {
{ 0, 0, 0 }
}; // First index on {X,Y,Z}
region.SetSize(size);
region.SetIndex(start);
// Pixel data is allocated
image->SetRegions(region);
image->Allocate(true); // initialize buffer to zero
// Software Guide : BeginLatex
//
// The individual position of a pixel inside the image is identified by a
// unique index. An index is an array of integers that defines the position
// of the pixel along each dimension of the image. The \code{IndexType}
// is automatically defined by the image and can be accessed using the
// scope operator \doxygen{Index}. The length of the array will match
// the dimensions of the associated image.
//
// The following code illustrates the declaration of an index variable and
// the assignment of values to each of its components. Please note that
// no \code{SmartPointer} is used to access the \code{Index}. This is
// because \code{Index} is a lightweight object that is not intended to be
// shared between objects. It is more efficient to produce multiple copies
// of these small objects than to share them using the SmartPointer
// mechanism.
//
// The following lines declare an instance of the index type and initialize
// its content in order to associate it with a pixel position in the image.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
const ImageType::IndexType pixelIndex = {
{ 27, 29, 37 }
}; // Position of {X,Y,Z}
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Having defined a pixel position with an index, it is then possible to
// access the content of the pixel in the image. The \code{GetPixel()}
// method allows us to get the value of the pixels.
//
// \index{itk::Image!GetPixel()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
ImageType::PixelType pixelValue = image->GetPixel(pixelIndex);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \code{SetPixel()} method allows us to set the value of the pixel.
//
// \index{itk::Image!SetPixel()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
image->SetPixel(pixelIndex, pixelValue + 1);
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// Please note that \code{GetPixel()} returns the pixel value using copy
// and not reference semantics. Hence, the method cannot be used to
// modify image data values.
//
// Remember that both \code{SetPixel()} and \code{GetPixel()} are
// inefficient and should only be used for debugging or for supporting
// interactions like querying pixel values by clicking with the mouse.
//
// Software Guide : EndLatex
return EXIT_SUCCESS;
}
itk::GTest::TypedefsAndConstructors::Dimension2::SizeType
ImageBaseType::SizeType SizeType
Definition: itkGTestTypedefsAndConstructors.h:49
itkImage.h
itk::GTest::TypedefsAndConstructors::Dimension2::IndexType
ImageBaseType::IndexType IndexType
Definition: itkGTestTypedefsAndConstructors.h:50
itk::GTest::TypedefsAndConstructors::Dimension2::RegionType
ImageBaseType::RegionType RegionType
Definition: itkGTestTypedefsAndConstructors.h:54
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:88
itk::ImageRegion::SetSize
void SetSize(const SizeType &size)
Definition: itkImageRegion.h:174