# Flip

VTKExamples/Cxx/Images/Flip

### Description

This example demonstrates how to flip an image over an axis.

Need a better source image (non-symmetrical!).

### Code

Flip.cxx

    #include <vtkImageData.h>
    #include <vtkImageCast.h>
    #include <vtkSmartPointer.h>
    #include <vtkImageMapper3D.h>
    #include <vtkImageFlip.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkInteractorStyleImage.h>
    #include <vtkRenderer.h>
    #include <vtkImageMandelbrotSource.h>
    #include <vtkImageActor.h>

    int main(int, char *[])
    {
      // Create an image
      vtkSmartPointer<vtkImageMandelbrotSource> source =
        vtkSmartPointer<vtkImageMandelbrotSource>::New();
      source->Update();

      vtkSmartPointer<vtkImageCast> castSource =
        vtkSmartPointer<vtkImageCast>::New();
      castSource->SetOutputScalarTypeToUnsignedChar();
      castSource->SetInputConnection(source->GetOutputPort());
      castSource->Update();

      vtkSmartPointer<vtkImageFlip> flipXFilter =
        vtkSmartPointer<vtkImageFlip>::New();
      flipXFilter->SetFilteredAxis(0); // flip x axis
      flipXFilter->SetInputConnection(source->GetOutputPort());
      flipXFilter->Update();

      vtkSmartPointer<vtkImageCast> castXFilter =
        vtkSmartPointer<vtkImageCast>::New();
      castXFilter->SetOutputScalarTypeToUnsignedChar();
      castXFilter->SetInputConnection(flipXFilter->GetOutputPort());
      castXFilter->Update();

      vtkSmartPointer<vtkImageFlip> flipYFilter =
        vtkSmartPointer<vtkImageFlip>::New();
      flipYFilter->SetFilteredAxis(1); // flip y axis
      flipYFilter->SetInputConnection(source->GetOutputPort());
      flipYFilter->Update();

      vtkSmartPointer<vtkImageCast> castYFilter =
        vtkSmartPointer<vtkImageCast>::New();
      castYFilter->SetOutputScalarTypeToUnsignedChar();
      castYFilter->SetInputConnection(flipYFilter->GetOutputPort());
      castYFilter->Update();

      vtkSmartPointer<vtkImageFlip> flipZFilter =
        vtkSmartPointer<vtkImageFlip>::New();
      flipZFilter->SetFilteredAxis(2); // flip z axis
      flipZFilter->SetInputConnection(source->GetOutputPort());
      flipZFilter->Update();

      vtkSmartPointer<vtkImageCast> castZFilter =
        vtkSmartPointer<vtkImageCast>::New();
      castZFilter->SetOutputScalarTypeToUnsignedChar();
      castZFilter->SetInputConnection(flipZFilter->GetOutputPort());
      castZFilter->Update();

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

      vtkSmartPointer<vtkImageActor> xActor =
        vtkSmartPointer<vtkImageActor>::New();
      xActor->GetMapper()->SetInputConnection(castXFilter->GetOutputPort());

      vtkSmartPointer<vtkImageActor> yActor =
        vtkSmartPointer<vtkImageActor>::New();
      yActor->GetMapper()->SetInputConnection(castYFilter->GetOutputPort());

      vtkSmartPointer<vtkImageActor> zActor =
        vtkSmartPointer<vtkImageActor>::New();
      zActor->GetMapper()->SetInputConnection(castZFilter->GetOutputPort());

      // Define viewport ranges
      // (xmin, ymin, xmax, ymax)
      double inputViewport[4] = {0.0, 0.0, 0.25, 1.0};
      double xViewport[4] = {0.25, 0.0, 0.5, 1.0};
      double yViewport[4] = {0.5, 0.0, 0.75, 1.0};
      double zViewport[4] = {0.75, 0.0, 1.0, 1.0};

      // Setup renderers
      vtkSmartPointer<vtkRenderer> inputRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      inputRenderer->SetViewport(inputViewport);
      inputRenderer->AddActor(inputActor);
      inputRenderer->ResetCamera();
      inputRenderer->SetBackground(.4, .5, .9);

      vtkSmartPointer<vtkRenderer> xRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      xRenderer->SetViewport(xViewport);
      xRenderer->AddActor(xActor);
      xRenderer->ResetCamera();
      xRenderer->SetBackground(.4, .5, .6);

      vtkSmartPointer<vtkRenderer> yRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      yRenderer->SetViewport(yViewport);
      yRenderer->AddActor(yActor);
      yRenderer->ResetCamera();
      yRenderer->SetBackground(.4, .5, .7);

      vtkSmartPointer<vtkRenderer> zRenderer =
        vtkSmartPointer<vtkRenderer>::New();
      zRenderer->SetViewport(zViewport);
      zRenderer->AddActor(zActor);
      zRenderer->ResetCamera();
      zRenderer->SetBackground(.4, .5, .8);

      // Setup render window
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->SetSize(1000, 250);
      renderWindow->AddRenderer(inputRenderer);
      renderWindow->AddRenderer(xRenderer);
      renderWindow->AddRenderer(yRenderer);
      renderWindow->AddRenderer(zRenderer);

      // Setup render window interactor
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      vtkSmartPointer<vtkInteractorStyleImage> style =
        vtkSmartPointer<vtkInteractorStyleImage>::New();

      renderWindowInteractor->SetInteractorStyle(style);

      // Render and start interaction
      renderWindowInteractor->SetRenderWindow(renderWindow);
      renderWindow->Render();
      renderWindowInteractor->Initialize();

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(Flip)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkImagingCore
      vtkImagingSources
      vtkInteractionStyle
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping Flip: ${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(Flip MACOSX_BUNDLE Flip.cxx )
      target_link_libraries(Flip PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(Flip MACOSX_BUNDLE Flip.cxx )
      target_link_libraries(Flip PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS Flip
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build Flip

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

    cd Flip/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:

    ./Flip

WINDOWS USERS

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