SphinxExamples/src/Filtering/ImageIntensity/SubtractTwoImages/Code.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
 *
 *         https://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"
#include "itkRescaleIntensityImageFilter.h"
#include "itkSubtractImageFilter.h"
 
#include "itkImageToVTKImageFilter.h"
 
#include "vtkVersion.h"
#include "vtkImageViewer.h"
#include "vtkImageMapper3D.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkSmartPointer.h"
#include "vtkImageActor.h"
#include "vtkInteractorStyleImage.h"
#include "vtkRenderer.h"
 
using ImageType = itk::Image<unsigned char, 2>;
 
static void
CreateImage1(ImageType::Pointer image);
static void
CreateImage2(ImageType::Pointer image);
 
int
main()
{
  auto image1 = ImageType::New();
  CreateImage1(image1);
 
  auto image2 = ImageType::New();
  CreateImage2(image2);
 
  using SubtractImageFilterType = itk::SubtractImageFilter<ImageType, ImageType>;
 
  auto subtractFilter = SubtractImageFilterType::New();
  subtractFilter->SetInput1(image1);
  subtractFilter->SetInput2(image2);
  subtractFilter->Update();
 
  // Visualize first image
  using ConnectorType = itk::ImageToVTKImageFilter<ImageType>;
  auto connector1 = ConnectorType::New();
  connector1->SetInput(image1);
 
  vtkSmartPointer<vtkImageActor> actor1 = vtkSmartPointer<vtkImageActor>::New();
#if VTK_MAJOR_VERSION <= 5
  actor1->SetInput(connector1->GetOutput());
#else
  connector1->Update();
  actor1->GetMapper()->SetInputData(connector1->GetOutput());
#endif
 
  // Visualize second image
  using ConnectorType = itk::ImageToVTKImageFilter<ImageType>;
  auto connector2 = ConnectorType::New();
  connector2->SetInput(image2);
 
  vtkSmartPointer<vtkImageActor> actor2 = vtkSmartPointer<vtkImageActor>::New();
 
#if VTK_MAJOR_VERSION <= 5
  actor2->SetInput(connector2->GetOutput());
#else
  connector2->Update();
  actor2->GetMapper()->SetInputData(connector2->GetOutput());
#endif
 
  // Visualize subtracted image
  auto subtractConnector = ConnectorType::New();
  subtractConnector->SetInput(subtractFilter->GetOutput());
 
  vtkSmartPointer<vtkImageActor> subtractActor = vtkSmartPointer<vtkImageActor>::New();
#if VTK_MAJOR_VERSION <= 5
  subtractActor->SetInput(subtractConnector->GetOutput());
#else
  subtractConnector->Update();
  subtractActor->GetMapper()->SetInputData(subtractConnector->GetOutput());
#endif
  // There will be one render window
  vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetSize(900, 300);
 
  vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);
 
  // Define viewport ranges
  // (xmin, ymin, xmax, ymax)
  double leftViewport[4] = { 0.0, 0.0, 0.33, 1.0 };
  double centerViewport[4] = { 0.33, 0.0, 0.66, 1.0 };
  double rightViewport[4] = { 0.66, 0.0, 1.0, 1.0 };
 
  // Setup both renderers
  vtkSmartPointer<vtkRenderer> leftRenderer = vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(leftRenderer);
  leftRenderer->SetViewport(leftViewport);
  leftRenderer->SetBackground(.6, .5, .4);
 
  vtkSmartPointer<vtkRenderer> centerRenderer = vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(centerRenderer);
  centerRenderer->SetViewport(centerViewport);
  centerRenderer->SetBackground(.4, .5, .6);
 
  vtkSmartPointer<vtkRenderer> rightRenderer = vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(rightRenderer);
  rightRenderer->SetViewport(rightViewport);
  rightRenderer->SetBackground(.4, .5, .6);
 
  // Add the sphere to the left and the cube to the right
  leftRenderer->AddActor(actor1);
  centerRenderer->AddActor(actor2);
  rightRenderer->AddActor(subtractActor);
 
  leftRenderer->ResetCamera();
  centerRenderer->ResetCamera();
  rightRenderer->ResetCamera();
 
  renderWindow->Render();
 
  vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New();
  interactor->SetInteractorStyle(style);
 
  interactor->Start();
 
  return EXIT_SUCCESS;
}
 
void
CreateImage1(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();
 
  // Make a square
  for (unsigned int r = 20; r < 80; ++r)
  {
    for (unsigned int c = 20; c < 80; ++c)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
 
      image->SetPixel(pixelIndex, 15);
    }
  }
}
 
 
void
CreateImage2(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();
 
  // Make another square
  for (unsigned int r = 40; r < 100; ++r)
  {
    for (unsigned int c = 40; c < 100; ++c)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
 
      image->SetPixel(pixelIndex, 15);
    }
  }
}