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# ImageContinuousErode3D

VTKEx/Cxx/Images/ImageContinuousErode3D

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

### Code

ImageContinuousErode3D.cxx

    #include <vtkSmartPointer.h>
    #include <vtkProperty.h>
    #include <vtkImageData.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageContinuousErode3D.h>
    #include <vtkPNGReader.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkDataSetMapper.h>

    int main(int argc, char *argv[])
    {
      vtkSmartPointer<vtkImageData> image =
        vtkSmartPointer<vtkImageData>::New();

      if(argc < 2)
      {
        // Create an image
        vtkSmartPointer<vtkImageCanvasSource2D> source =
          vtkSmartPointer<vtkImageCanvasSource2D>::New();
        source->SetScalarTypeToUnsignedChar();
        source->SetExtent(0, 200, 0, 200, 0, 0);
        source->SetDrawColor(0,0,0);
        source->FillBox(0,200,0,200);
        source->SetDrawColor(255,0,0);
        source->FillBox(100,150,100,150);
        source->Update();
        image->ShallowCopy(source->GetOutput());
      }
      else
      {
        vtkSmartPointer<vtkPNGReader> reader =
          vtkSmartPointer<vtkPNGReader>::New();
        reader->SetFileName(argv[1]);
        reader->Update();
        image->ShallowCopy(reader->GetOutput());
      }

      vtkSmartPointer<vtkImageContinuousErode3D> erodeFilter =
        vtkSmartPointer<vtkImageContinuousErode3D>::New();
      erodeFilter->SetInputData(image);
      erodeFilter->SetKernelSize(10,10,1);
      erodeFilter->Update();

      vtkSmartPointer<vtkDataSetMapper> originalMapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      originalMapper->SetInputData(image);
      originalMapper->Update();

      vtkSmartPointer<vtkActor> originalActor =
        vtkSmartPointer<vtkActor>::New();
      originalActor->SetMapper(originalMapper);

      vtkSmartPointer<vtkDataSetMapper> erodedMapper =
        vtkSmartPointer<vtkDataSetMapper>::New();
      erodedMapper->SetInputConnection(erodeFilter->GetOutputPort());
      erodedMapper->Update();

      vtkSmartPointer<vtkActor> erodedActor =
        vtkSmartPointer<vtkActor>::New();
      erodedActor->SetMapper(erodedMapper);

      // Visualize
      double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
      double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(600, 300);

      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(renderWindow);

      vtkSmartPointer<vtkRenderer> leftRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderWindow->AddRenderer(leftRenderer);
      leftRenderer->SetViewport(leftViewport);
      leftRenderer->SetBackground(.6, .5, .4);

      vtkSmartPointer<vtkRenderer> rightRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderWindow->AddRenderer(rightRenderer);
      rightRenderer->SetViewport(rightViewport);
      rightRenderer->SetBackground(.4, .5, .6);

      leftRenderer->AddActor(originalActor);
      rightRenderer->AddActor(erodedActor);

      leftRenderer->ResetCamera();
      rightRenderer->SetActiveCamera(leftRenderer->GetActiveCamera());

      renderWindow->Render();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ImageContinuousErode3D)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkIOImage
      vtkImagingMorphological
      vtkImagingSources
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ImageContinuousErode3D: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(ImageContinuousErode3D MACOSX_BUNDLE ImageContinuousErode3D.cxx )
      target_link_libraries(ImageContinuousErode3D PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ImageContinuousErode3D MACOSX_BUNDLE ImageContinuousErode3D.cxx )
      target_link_libraries(ImageContinuousErode3D PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ImageContinuousErode3D
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ImageContinuousErode3D

Click here to download ImageContinuousErode3D and its CMakeLists.txt file. Once the tarball ImageContinuousErode3D.tar has been downloaded and extracted,

    cd ImageContinuousErode3D/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./ImageContinuousErode3D

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.