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# WindowModifiedEvent

VTKEx/Cxx/Utilities/WindowModifiedEvent

### Description

This example limits the horizontal window size to 400.

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

WindowModifiedEvent.cxx

    #include <vtkSphereSource.h>
    #include <vtkPolyData.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkCallbackCommand.h>

    void WindowModifiedCallback( vtkObject*
                          caller, long unsigned int vtkNotUsed(eventId), void* vtkNotUsed(clientData), void* vtkNotUsed(callData) )
    {
      std::cout << "Window modified" << std::endl;
      std::cout << caller->GetClassName() << std::endl;

      vtkRenderWindow* window = static_cast<vtkRenderWindow*>(caller);
      int* windowSize = window->GetSize();
      std::cout << "Size: " << windowSize[0] << " " << windowSize[1] << std::endl;

      if(windowSize[0] > 400)
      {
        window->SetSize(400, windowSize[1]);
        window->Render();
        window->Modified();
        window->Render();

      }
    }

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

      // Create a mapper and actor
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(sphereSource->GetOutputPort());

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

      // Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      // Add the actor to the scene
      renderer->AddActor(actor);
      renderer->SetBackground(1,1,1); // Background color white

      vtkSmartPointer<vtkCallbackCommand> m_pModifiedCallback =
        vtkSmartPointer<vtkCallbackCommand>::New();
      m_pModifiedCallback->SetCallback (WindowModifiedCallback);
      //m_pModifiedCallback->SetClientData(this);

      renderWindow->AddObserver(vtkCommand::ModifiedEvent,m_pModifiedCallback);

      // Render and interact
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(WindowModifiedEvent)

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

### Download and Build WindowModifiedEvent

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

    cd WindowModifiedEvent/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:

    ./WindowModifiedEvent

WINDOWS USERS

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