Skip to content

MoveAGlyph

vtk-examples/Cxx/Interaction/MoveAGlyph

Description

This example allows the user to reposition a glyph. It does this by faking the interactor into thinking that a new actor (MoveActor) is the object to be interacted with. We use the array generated by glyph3D->GeneratePointIdsOn() to determine the point associated with the glyph that the user selected. A "ghost" actor of the selected glyph is generated (because all of the glyphs are part of the same actor, so they would all move together). This actor is moved, and its final position is used to update the point in the original data set.

Question

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

Code

MoveAGlyph.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkCellPicker.h>
#include <vtkGlyph3D.h>
#include <vtkIdTypeArray.h>
#include <vtkInteractorStyleTrackballActor.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointData.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>

namespace {

// Define interaction style.
class InteractorStyleMoveGlyph : public vtkInteractorStyleTrackballActor
{
public:
  static InteractorStyleMoveGlyph* New();
  vtkTypeMacro(InteractorStyleMoveGlyph, vtkInteractorStyleTrackballActor);

  InteractorStyleMoveGlyph()
  {
    this->MoveSphereSource = vtkSmartPointer<vtkSphereSource>::New();
    this->MoveSphereSource->SetRadius(.1);
    this->MoveSphereSource->Update();

    this->MoveMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    this->MoveMapper->SetInputConnection(
        this->MoveSphereSource->GetOutputPort());

    this->MoveActor = vtkSmartPointer<vtkActor>::New();
    this->MoveActor->SetMapper(this->MoveMapper);
    this->MoveActor->GetProperty()->SetColor(
        this->color->GetColor3d("Pink").GetData());
    // this->MoveActor->VisibilityOff();

    this->Move = false;
  }

  void OnMouseMove() override
  {
    if (!this->Move)
    {
      return;
    }

    vtkInteractorStyleTrackballActor::OnMouseMove();
  }

  void OnMiddleButtonUp() override
  {
    // Forward events.
    vtkInteractorStyleTrackballActor::OnMiddleButtonUp();
    this->Move = false;
    this->MoveActor->VisibilityOff();

    this->Data->GetPoints()->SetPoint(this->SelectedPoint,
                                      this->MoveActor->GetPosition());
    this->Data->Modified();
    this->GetCurrentRenderer()->Render();
    this->GetCurrentRenderer()->GetRenderWindow()->Render();
  }
  void OnMiddleButtonDown() override
  {
    // Forward events.
    vtkInteractorStyleTrackballActor::OnMiddleButtonDown();
    this->MoveActor->VisibilityOn();
    if (static_cast<vtkCellPicker*>(this->InteractionPicker)->GetPointId() >= 0)
    {
      vtkIdType id =
          dynamic_cast<vtkIdTypeArray*>(
              this->GlyphData->GetPointData()->GetArray("InputPointIds"))
              ->GetValue(static_cast<vtkCellPicker*>(this->InteractionPicker)
                             ->GetPointId());
      std::cout << "Id: " << id << std::endl;
      this->Move = true;
      this->SelectedPoint = id;

      double p[3];
      this->Data->GetPoint(id, p);
      std::cout << "p: " << p[0] << " " << p[1] << " " << p[2] << std::endl;
      this->MoveActor->SetPosition(p);
    }

    this->GetCurrentRenderer()->AddActor(this->MoveActor);
    this->InteractionProp = this->MoveActor;
  }
  vtkNew<vtkNamedColors> color;

  vtkPolyData* Data;
  vtkPolyData* GlyphData;

  vtkSmartPointer<vtkPolyDataMapper> MoveMapper;
  vtkSmartPointer<vtkActor> MoveActor;
  vtkSmartPointer<vtkSphereSource> MoveSphereSource;

  bool Move;
  vtkIdType SelectedPoint;
};
vtkStandardNewMacro(InteractorStyleMoveGlyph);

} // namespace

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

  vtkNew<vtkPoints> points;
  points->InsertNextPoint(0, 0, 0);
  points->InsertNextPoint(1, 0, 0);
  points->InsertNextPoint(2, 0, 0);

  vtkNew<vtkPolyData> input;
  input->SetPoints(points);

  vtkNew<vtkSphereSource> glyphSource;
  glyphSource->SetRadius(0.1);
  glyphSource->Update();

  vtkNew<vtkGlyph3D> glyph3D;
  glyph3D->GeneratePointIdsOn();
  glyph3D->SetSourceConnection(glyphSource->GetOutputPort());
  glyph3D->SetInputData(input);
  glyph3D->SetScaleModeToDataScalingOff();
  glyph3D->Update();

  // Create a mapper and actor.
  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(glyph3D->GetOutputPort());

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

  // Visualize
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("MoveAGlyph");

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

  renderer->AddActor(actor);
  renderer->SetBackground(color->GetColor3d("Burlywood").GetData());

  renderWindow->Render();

  vtkNew<InteractorStyleMoveGlyph> style;
  renderWindowInteractor->SetInteractorStyle(style);
  style->Data = input;
  style->GlyphData = glyph3D->GetOutput();

  renderer->GetActiveCamera()->Zoom(0.9);
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(MoveAGlyph)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "MoveAGlyph: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(MoveAGlyph MACOSX_BUNDLE MoveAGlyph.cxx )
  target_link_libraries(MoveAGlyph PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS MoveAGlyph
  MODULES ${VTK_LIBRARIES}
)

Download and Build MoveAGlyph

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

cd MoveAGlyph/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:

./MoveAGlyph

WINDOWS USERS

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