Slider2D

VTKEx/Cxx/Widgets/Slider2D

Description

This example demonstrates how to use a slider that is drawn in window coordinates - so if you move the scene the slider is not affected. Contrast this with the 3D slider widget that remains at a fixed location in the world coordinates.

If the callback is connected to InteractionEvent, the scene will update immediately. This is not ideal if the re-rendering takes significant time as it will make the interaction very choppy. If you want to move the slider and have the scene update when the mouse button is released, connect the callback to EndInteractionEvent instead.

Note

This original source code for this example is here.

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

Slider2D.cxx

#include <vtkSphereSource.h>
#include <vtkTextProperty.h>
#include <vtkProperty2D.h>
#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkSliderWidget.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkCommand.h>
#include <vtkWidgetEvent.h>
#include <vtkCallbackCommand.h>
#include <vtkWidgetEventTranslator.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkSliderWidget.h>
#include <vtkSliderRepresentation2D.h>
#include <vtkProperty.h>

// This does the actual work.
// Callback for the interaction
class vtkSliderCallback : public vtkCommand
{
public:
  static vtkSliderCallback *New()
  {
    return new vtkSliderCallback;
  }
  virtual void Execute(vtkObject *caller, unsigned long, void*)
  {
    vtkSliderWidget *sliderWidget =
      reinterpret_cast<vtkSliderWidget*>(caller);
    this->SphereSource->SetPhiResolution(static_cast<vtkSliderRepresentation *>(sliderWidget->GetRepresentation())->GetValue());
    this->SphereSource->SetThetaResolution(static_cast<vtkSliderRepresentation *>(sliderWidget->GetRepresentation())->GetValue());
  }
  vtkSliderCallback():SphereSource(0) {}
  vtkSphereSource *SphereSource;
};

int main (int, char *[])
{
  // A sphere
  vtkSmartPointer<vtkSphereSource> sphereSource =
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(4.0);

  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(sphereSource->GetOutputPort());

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

  // A renderer and render window
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);

  // An interactor
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actors to the scene
  renderer->AddActor(actor);

  // Render an image (lights and cameras are created automatically)
  renderWindow->Render();

  vtkSmartPointer<vtkSliderRepresentation2D> sliderRep =
    vtkSmartPointer<vtkSliderRepresentation2D>::New();

  sliderRep->SetMinimumValue(3.0);
  sliderRep->SetMaximumValue(20.0);
  sliderRep->SetValue(5.0);
  sliderRep->SetTitleText("Sphere Resolution");

  // Set color properties:
  // Change the color of the knob that slides
  sliderRep->GetSliderProperty()->SetColor(1,0,0);//red

  // Change the color of the text indicating what the slider controls
  sliderRep->GetTitleProperty()->SetColor(1,0,0);//red

  // Change the color of the text displaying the value
  sliderRep->GetLabelProperty()->SetColor(1,0,0);//red

  // Change the color of the knob when the mouse is held on it
  sliderRep->GetSelectedProperty()->SetColor(0,1,0);//green

  // Change the color of the bar
  sliderRep->GetTubeProperty()->SetColor(1,1,0);//yellow

  // Change the color of the ends of the bar
  sliderRep->GetCapProperty()->SetColor(1,1,0);//yellow

  sliderRep->GetPoint1Coordinate()->SetCoordinateSystemToDisplay();
  sliderRep->GetPoint1Coordinate()->SetValue(40 ,40);
  sliderRep->GetPoint2Coordinate()->SetCoordinateSystemToDisplay();
  sliderRep->GetPoint2Coordinate()->SetValue(100, 40);

  vtkSmartPointer<vtkSliderWidget> sliderWidget =
    vtkSmartPointer<vtkSliderWidget>::New();
  sliderWidget->SetInteractor(renderWindowInteractor);
  sliderWidget->SetRepresentation(sliderRep);
  sliderWidget->SetAnimationModeToAnimate();
  sliderWidget->EnabledOn();

  vtkSmartPointer<vtkSliderCallback> callback =
    vtkSmartPointer<vtkSliderCallback>::New();
  callback->SphereSource = sphereSource;

  sliderWidget->AddObserver(vtkCommand::InteractionEvent,callback);

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

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(Slider2D)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersSources
  vtkvtkInteractionStyle
  vtkvtkInteractionWidgets
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping Slider2D: ${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(Slider2D MACOSX_BUNDLE Slider2D.cxx )
  target_link_libraries(Slider2D PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(Slider2D MACOSX_BUNDLE Slider2D.cxx )
  target_link_libraries(Slider2D PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS Slider2D
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build Slider2D

Click here to download Slider2D and its CMakeLists.txt file. Once the tarball Slider2D.tar has been downloaded and extracted,

cd Slider2D/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:

./Slider2D

WINDOWS USERS

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