ITK  5.3.0
Insight Toolkit
Examples/DataRepresentation/Image/RGBImage.cxx
/*=========================================================================
*
* Copyright NumFOCUS
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#include "itkImage.h"
// Software Guide : BeginLatex
//
// Thanks to the flexibility offered by the
// \href{http://www.boost.org/more/generic_programming.html}{Generic
// Programming} style on which ITK is based, it is possible to
// instantiate images of arbitrary pixel type. The following example
// illustrates how a color image with RGB pixels can be defined.
//
// A class intended to support the RGB pixel type is available in ITK. You
// could also define your own pixel class and use it to instantiate a
// custom image type. In order to use the \doxygen{RGBPixel} class, it is
// necessary to include its header file.
//
// \index{itk::RGBPixel}
// \index{itk::RGBPixel!Image}
// \index{itk::RGBPixel!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkRGBPixel.h"
// Software Guide : EndCodeSnippet
int
main(int, char * argv[])
{
// Software Guide : BeginLatex
//
// The RGB pixel class is templated over a type used to represent each one
// of the red, green and blue pixel components. A typical instantiation of
// the templated class is as follows.
//
// \index{itk::RGBPixel!Instantiation}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using PixelType = itk::RGBPixel<unsigned char>;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The type is then used as the pixel template parameter of the image.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ImageType = itk::Image<PixelType, 3>;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The image type can be used to instantiate other filter, for example,
// an \doxygen{ImageFileReader} object that will read the image from a
// file.
//
// \index{itk::ImageFileReader!RGB Image}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
using ReaderType = itk::ImageFileReader<ImageType>;
// Software Guide : EndCodeSnippet
ReaderType::Pointer reader = ReaderType::New();
const char * const filename = argv[1];
reader->SetFileName(filename);
reader->Update();
ImageType::Pointer image = reader->GetOutput();
const ImageType::IndexType pixelIndex = { { 25, 35, 0 } };
// Software Guide : BeginLatex
//
// Access to the color components of the pixels can now be performed using
// the methods provided by the RGBPixel class.
//
// \index{itk::Image!GetPixel()}
// \index{itk::RGBPixel!GetRed()}
// \index{itk::RGBPixel!GetGreen()}
// \index{itk::RGBPixel!GetBlue()}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
PixelType onePixel = image->GetPixel(pixelIndex);
PixelType::ValueType red = onePixel.GetRed();
PixelType::ValueType green = onePixel.GetGreen();
PixelType::ValueType blue = onePixel.GetBlue();
// Software Guide : EndCodeSnippet
std::cout << "Pixel values from GetRed,GetGreen,GetBlue:" << std::endl;
std::cout << "Red = "
<< std::endl;
std::cout << "Green = "
<< std::endl;
std::cout << "Blue = "
<< std::endl;
// Software Guide : BeginLatex
//
// The subindex notation can also be used since the \doxygen{RGBPixel}
// inherits the \code{[]} operator from the \doxygen{FixedArray} class.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
red = onePixel[0]; // extract Red component
green = onePixel[1]; // extract Green component
blue = onePixel[2]; // extract Blue component
std::cout << "Pixel values:" << std::endl;
std::cout << "Red = "
<< std::endl;
std::cout << "Green = "
<< std::endl;
std::cout << "Blue = "
<< std::endl;
// Software Guide : EndCodeSnippet
// Lets repeat that both \code{SetPixel()} and \code{GetPixel()} are
// inefficient and should only be used for debugging purposes or for
// implementing interactions with a graphical user interface such as
// querying pixel value by clicking with the mouse.
//
return EXIT_SUCCESS;
}
itk::RGBPixel
Represent Red, Green and Blue components for color images.
Definition: itkRGBPixel.h:58
itkRGBPixel.h
itkImageFileReader.h
itkImage.h
itk::ImageFileReader
Data source that reads image data from a single file.
Definition: itkImageFileReader.h:75
itk::GTest::TypedefsAndConstructors::Dimension2::IndexType
ImageBaseType::IndexType IndexType
Definition: itkGTestTypedefsAndConstructors.h:50
itk::NumericTraits::PrintType
T PrintType
Definition: itkNumericTraits.h:68
itk::Image
Templated n-dimensional image class.
Definition: itkImage.h:88