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MouseEvents

vtk-examples/Cxx/Interaction/MouseEvents


Description

This example shows how to subclass an interactor style to implement custom behaviors.

See MouseEventsObserver for a different approach that uses an existing interactor style class and adds an event observer to it.

Other languages

See (Python)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

MouseEvents.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointPicker.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>

namespace {

// Define interaction style
class customMouseInteractorStyle : public vtkInteractorStyleTrackballCamera
{
public:
  static customMouseInteractorStyle* New();
  vtkTypeMacro(customMouseInteractorStyle, vtkInteractorStyleTrackballCamera);

  virtual void OnLeftButtonDown() override
  {
    std::cout << "Pressed left mouse button." << std::endl;
    // Forward events
    vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
  }

  virtual void OnMiddleButtonDown() override
  {
    std::cout << "Pressed middle mouse button." << std::endl;
    // Forward events
    vtkInteractorStyleTrackballCamera::OnMiddleButtonDown();
  }

  virtual void OnRightButtonDown() override
  {
    std::cout << "Pressed right mouse button." << std::endl;
    // Forward events
    vtkInteractorStyleTrackballCamera::OnRightButtonDown();
  }
};

vtkStandardNewMacro(customMouseInteractorStyle);

} // namespace

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());

  vtkNew<vtkRenderer> renderer;
  renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());
  renderer->AddActor(actor);

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

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

  vtkNew<customMouseInteractorStyle> style;
  renderWindowInteractor->SetInteractorStyle(style);

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

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(MouseEvents)

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

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

Download and Build MouseEvents

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

cd MouseEvents/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:

./MouseEvents

WINDOWS USERS

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