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UserEvent

vtk-examples/Cxx/Interaction/UserEvent


Question

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Code

UserEvent.cxx

#include <vtkActor.h>
#include <vtkCallbackCommand.h>
#include <vtkCommand.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>

#include "vtkTestFilter.h"

namespace {

void CallbackFunction(vtkObject* caller, long unsigned int eventId,
                      void* clientData, void* callData);

}

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  sphereSource->Update();

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(sphereSource->GetOutputPort());

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("MistyRose").GetData());

  // Create a renderer, render window, and interactor
  vtkNew<vtkRenderer> renderer;
  renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("UserEvent");

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  vtkNew<vtkTestFilter> filter;

  vtkNew<vtkCallbackCommand> callback;
  callback->SetCallback(CallbackFunction);
  filter->AddObserver(filter->RefreshEvent, callback);

  filter->Update();

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

  return EXIT_SUCCESS;
}

namespace {

void CallbackFunction(vtkObject* /* caller */, long unsigned int /* eventId */,
                      void* /* clientData */, void* /* callData */)
{
  std::cout << "CallbackFunction called." << std::endl;
}

} // namespace

vtkTestFilter.h

#ifndef __vtkTestFilter_h
#define __vtkTestFilter_h

#include <vtkPolyDataAlgorithm.h>

class vtkTestFilter : public vtkPolyDataAlgorithm
{
public:
  vtkTypeMacro(vtkTestFilter,vtkPolyDataAlgorithm);
  static vtkTestFilter *New();

  int RefreshEvent;

protected:
  vtkTestFilter();

  int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *) override;

private:
  vtkTestFilter(const vtkTestFilter&);  // Not implemented.
  void operator=(const vtkTestFilter&);  // Not implemented.

};

#endif

#include <vtkObjectFactory.h>
#include <vtkCommand.h>
#include <vtkStreamingDemandDrivenPipeline.h>
#include <vtkInformationVector.h>
#include <vtkInformation.h>
#include <vtkDataObject.h>
#include <vtkSmartPointer.h>
#include <vtkAppendPolyData.h>
#include <vtkSphereSource.h>

vtkStandardNewMacro(vtkTestFilter);

vtkTestFilter::vtkTestFilter()
{
  this->SetNumberOfInputPorts(0);

  this->RefreshEvent = vtkCommand::UserEvent + 1;

}

int vtkTestFilter::RequestData(vtkInformation *vtkNotUsed(request),
 vtkInformationVector **,
 vtkInformationVector *)
{
  // Get the info object
//  auto outInfo = outputVector->GetInformationObject(0);

//  auto output = vtkPolyData::SafeDownCast(
//      outInfo->Get(vtkDataObject::DATA_OBJECT()));
  this->InvokeEvent(this->RefreshEvent, nullptr);

  return 1;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(UserEvent)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkFiltersSources
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping UserEvent: ${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(UserEvent MACOSX_BUNDLE UserEvent.cxx )
  target_link_libraries(UserEvent PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(UserEvent MACOSX_BUNDLE UserEvent.cxx )
  target_link_libraries(UserEvent PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS UserEvent
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build UserEvent

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

cd UserEvent/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:

./UserEvent

WINDOWS USERS

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