# ImageMathematics

VTKExamples/Cxx/Images/ImageMathematics

### Code

ImageMathematics.cxx

    #include <vtkSmartPointer.h>
    #include <vtkImageMapper3D.h>
    #include <vtkMath.h>
    #include <vtkImageData.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkImageMathematics.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageActor.h>

    int main(int, char *[])
    {
      // Create an image
      vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      imageSource->SetNumberOfScalarComponents(3);
      imageSource->SetScalarTypeToUnsignedChar();
      imageSource->SetExtent(0, 4, 0, 4, 0, 0);
      imageSource->SetDrawColor(100.0, 0, 0);
      imageSource->FillBox(0, 4, 0, 4);
      imageSource->Update();

      vtkSmartPointer<vtkImageMathematics> imageMath =
        vtkSmartPointer<vtkImageMathematics>::New();
      imageMath->SetOperationToMultiplyByK();
      imageMath->SetConstantK(2.0);
      imageMath->SetInputConnection(imageSource->GetOutputPort());
      imageMath->Update();

      // Create actors
      vtkSmartPointer<vtkImageActor> originalActor =
        vtkSmartPointer<vtkImageActor>::New();
      originalActor->GetMapper()->SetInputConnection(
        imageSource->GetOutputPort());

      vtkSmartPointer<vtkImageActor> mathActor =
        vtkSmartPointer<vtkImageActor>::New();
      mathActor->GetMapper()->SetInputConnection(
        imageMath->GetOutputPort());

      // Define viewport ranges
      // (xmin, ymin, xmax, ymax)
      double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
      double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

      // Setup renderers
      vtkSmartPointer<vtkRenderer> originalRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      originalRenderer->SetViewport(leftViewport);
      originalRenderer->AddActor(originalActor);
      originalRenderer->ResetCamera();
      originalRenderer->SetBackground(.4, .5, .6);

      vtkSmartPointer<vtkRenderer> mathRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      mathRenderer->SetViewport(rightViewport);
      mathRenderer->AddActor(mathActor);
      mathRenderer->ResetCamera();
      mathRenderer->SetBackground(.4, .5, .7);

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

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

      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();
      renderWindowInteractor->SetInteractorStyle(style);

      renderWindowInteractor->Start();
      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ImageMathematics)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(ImageMathematics MACOSX_BUNDLE ImageMathematics.cxx)

    target_link_libraries(ImageMathematics ${VTK_LIBRARIES})

### Download and Build ImageMathematics

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

    cd ImageMathematics/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:

    ./ImageMathematics

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