# CornerAnnotation

VTKExamples/Cxx/Visualization/CornerAnnotation

### Code

CornerAnnotation.cxx

    #include <vtkSmartPointer.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkTextProperty.h>
    #include <vtkSphereSource.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkCornerAnnotation.h>

    int main( int, char *[] )
    {
      vtkSmartPointer<vtkSphereSource> sphereSource =
          vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();

      vtkSmartPointer<vtkPolyDataMapper> mapper =
          vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection( sphereSource->GetOutputPort() );

      vtkSmartPointer<vtkActor> actor =
          vtkSmartPointer<vtkActor>::New();
      actor->SetMapper( mapper );

      // Visualize
      vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer( renderer );

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

       // Annotate the image with window/level and mouse over pixel information
      vtkSmartPointer<vtkCornerAnnotation> cornerAnnotation =
          vtkSmartPointer<vtkCornerAnnotation>::New();
      cornerAnnotation->SetLinearFontScaleFactor( 2 );
      cornerAnnotation->SetNonlinearFontScaleFactor( 1 );
      cornerAnnotation->SetMaximumFontSize( 20 );
      cornerAnnotation->SetText( 0, "lower left" );
      cornerAnnotation->SetText( 1, "lower right" );
      cornerAnnotation->SetText( 2, "upper left" );
      cornerAnnotation->SetText( 3, "upper right" );
      cornerAnnotation->GetTextProperty()->SetColor( 1, 0, 0 );

      renderer->AddViewProp( cornerAnnotation );

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(CornerAnnotation)

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

### Download and Build CornerAnnotation

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

    cd CornerAnnotation/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:

    ./CornerAnnotation

WINDOWS USERS

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