ITK/Examples/SimpleOperations/Transparency

This example demonstrates how to assign transparency to pixels in an image. It then writes the result to a tif file for inspection and verification.

Transparency.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileWriter.h"
3. include "itkImageRegionIterator.h"
4. include "itkTIFFImageIO.h"
5. include "itkRGBAPixel.h"

int main(int argc, char *argv[]) {

 std::string outputFilename;
 if(argc > 1)
   {
   outputFilename = argv[1];
   }
 else
   {
   outputFilename = "test.tif";
   }

 typedef itk::RGBAPixel<unsigned char> PixelType;
 typedef itk::Image< PixelType, 2>  ImageType;

 ImageType::RegionType region;
 ImageType::IndexType start;
 start[0] = 0;
 start[1] = 0;

 ImageType::SizeType size;
 size[0] = 200;
 size[1] = 300;

 region.SetSize(size);
 region.SetIndex(start);

 ImageType::Pointer image = ImageType::New();
 image->SetRegions(region);
 image->Allocate();

 itk::ImageRegionIterator<ImageType> imageIterator(image,region);

 while(!imageIterator.IsAtEnd())
   {
   ImageType::PixelType pixel = imageIterator.Get();
 
   if(imageIterator.GetIndex()[0] > 100)
     {
     pixel.SetRed(0);
     pixel.SetGreen(255);
     pixel.SetBlue(0);
     //pixel.SetAlpha(255); // invisible
     pixel.SetAlpha(122);
     }
   else
     {
     pixel.SetRed(255);
     pixel.SetGreen(0);
     pixel.SetBlue(0);
     pixel.SetAlpha(0.5);
     }
   imageIterator.Set(pixel);
   
   ++imageIterator;
 }

 typedef  itk::ImageFileWriter< ImageType  > WriterType;
 typedef  itk::TIFFImageIO TIFFIOType;
 WriterType::Pointer writer = WriterType::New();
 TIFFIOType::Pointer tiffIO = TIFFIOType::New();
 tiffIO->SetPixelType(itk::ImageIOBase::RGBA);
 writer->SetFileName(outputFilename);
 writer->SetInput(image);
 writer->SetImageIO(tiffIO);
 writer->Update();

 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

<source lang="cmake"> cmake_minimum_required(VERSION 2.6)

PROJECT(Transparency)

FIND_PACKAGE(ITK REQUIRED) INCLUDE(${ITK_USE_FILE})

ADD_EXECUTABLE(Transparency Transparency.cxx) TARGET_LINK_LIBRARIES(Transparency ITKIO ITKBasicFilters ITKCommon )

</source>