SeedWidget

Description¶

This example demonstrates how to use vtkSeedWidget, which generates (seeds) points to be placed in the scene in the locations where the user clicks.

The points can then be used for operations like connectivity, segmentation, and region growing. For an example using a custom callback where such operations can be assembled, see SeedWidgetWithCustomCallback.

Other languages

See (Java)

Question

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

Code¶

SeedWidget.cxx

#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPointHandleRepresentation2D.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkProperty2D.h> // For setting the color in the handles
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSeedRepresentation.h>
#include <vtkSeedWidget.h>
#include <vtkSphereSource.h>

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

  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->Update();

  // Create a mapper and actor
  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(sphereSource->GetOutputPort());
  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("MidnightBlue").GetData());

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

  vtkNew<vtkRenderWindow> window;
  window->AddRenderer(renderer);
  window->SetWindowName("SeedWidget");

  vtkNew<vtkRenderWindowInteractor> interactor;
  interactor->SetRenderWindow(window);

  // Create the representation for the seed widget and for its handles
  vtkNew<vtkPointHandleRepresentation2D> handleRep;
  handleRep->GetProperty()->SetColor(colors->GetColor3d("Red").GetData());
  vtkNew<vtkSeedRepresentation> widgetRep;
  widgetRep->SetHandleRepresentation(handleRep);

  // Create the seed widget
  vtkNew<vtkSeedWidget> seedWidget;
  seedWidget->SetInteractor(interactor);
  seedWidget->SetRepresentation(widgetRep);

  seedWidget->On();
  window->Render();
  interactor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(SeedWidget)

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

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

Download and Build SeedWidget¶

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

cd SeedWidget/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:

./SeedWidget

WINDOWS USERS

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