WikiExamples/ImageProcessing/CropImageFilter.cxx

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkImageFileReader.h"
#include "itkCropImageFilter.h"

#include "itksys/SystemTools.hxx"

#include "QuickView.h"

using PixelType = itk::RGBPixel<unsigned char>;
using ImageType = itk::Image<PixelType, 2>;

static void CreateImage(ImageType::Pointer image);

int main(int argc, char *argv[])
{
  ImageType::Pointer image = ImageType::New();
  ImageType::SizeType cropSize;
  std::stringstream desc;

  if (argc > 1)
    {
    using ReaderType = itk::ImageFileReader<ImageType>;
    ReaderType::Pointer reader = ReaderType::New();
    reader->SetFileName( argv[1] );
    if (argc > 2)
      {
      cropSize[0] = atoi(argv[2]);
      cropSize[1] = atoi(argv[3]);
      }
    reader->Update();
    image = reader->GetOutput();
    desc << itksys::SystemTools::GetFilenameName(argv[1]);
    }
  else
    {
    CreateImage(image);
    cropSize[0] = 10;
    cropSize[1] = 14;
    desc << "Synthetic image";
    }

  using CropImageFilterType = itk::CropImageFilter <ImageType, ImageType>;

  CropImageFilterType::Pointer cropFilter
    = CropImageFilterType::New();
  cropFilter->SetInput(image);
  // The SetBoundaryCropSize( cropSize ) method specifies the size of
  // the boundary to be cropped at both the uppper & lower ends of the
  // image eg. cropSize/2 pixels will be removed at both upper & lower
  // extents

  cropFilter->SetBoundaryCropSize(cropSize);

  // The below three lines are equivalent to the above two lines:
  //ImageType::SizeType halfCropSize = {5,7};
  //cropFilter->SetUpperBoundaryCropSize(halfCropSize);
  //cropFilter->SetLowerBoundaryCropSize(halfCropSize);

  QuickView viewer;
  viewer.AddRGBImage(
    image.GetPointer(),
    true,
    desc.str());  

  std::stringstream desc2;
  desc2 << "CropImageFilter, crop size = {"
        << cropSize[0] << ", " << cropSize[1] << "}";
  viewer.AddRGBImage(
    cropFilter->GetOutput(),
    true,
    desc2.str());  

  viewer.Visualize();

  return EXIT_SUCCESS;
}

void CreateImage(ImageType::Pointer image)
{
  // Create an image with 2 connected components
  ImageType::RegionType region;
  ImageType::IndexType start;
  start[0] = 0;
  start[1] = 0;

  ImageType::SizeType size;
  unsigned int NumRows = 200;
  unsigned int NumCols = 300;
  size[0] = NumRows;
  size[1] = NumCols;

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

  image->SetRegions(region);
  image->Allocate();
  image->FillBuffer( itk::NumericTraits<ImageType::PixelType>::Zero);

  // Make a rectangle, centered at (100,150) with sides 160 & 240
  // This provides a 20 x 30 border around the square for the crop filter to remove
  for(unsigned int r = 20; r < 180; r++)
    {
    for(unsigned int c = 30; c < 270; c++)
      {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
      
      image->SetPixel(pixelIndex, 200);
      }
    }
}