VTK/Examples/Cxx/Utilities/WindowModifiedEvent

#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;
}