# SeedWidget

VTKExamples/Cxx/Widgets/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.

### Code

SeedWidget.cxx

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

    int main( int vtkNotUsed( argc ), char* vtkNotUsed( argv )[] )
    {
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->Update();

      // Create a mapper and actor
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(sphereSource->GetOutputPort());
      vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);

      vtkSmartPointer<vtkRenderWindow> window =
        vtkSmartPointer<vtkRenderWindow>::New();
      window->AddRenderer( renderer );

      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow( window );

      // Create the representation for the seed widget and for its handles
      vtkSmartPointer<vtkPointHandleRepresentation2D> handleRep =
        vtkSmartPointer<vtkPointHandleRepresentation2D>::New();
      handleRep->GetProperty()->SetColor( 1, 1, 0 ); // Make the handles yellow
      vtkSmartPointer<vtkSeedRepresentation> widgetRep =
        vtkSmartPointer<vtkSeedRepresentation>::New();
      widgetRep->SetHandleRepresentation( handleRep );

      // Create the seed widget
      vtkSmartPointer<vtkSeedWidget> seedWidget =
        vtkSmartPointer<vtkSeedWidget>::New();
      seedWidget->SetInteractor( interactor );
      seedWidget->SetRepresentation( widgetRep );

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

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(SeedWidget)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(SeedWidget MACOSX_BUNDLE SeedWidget.cxx )

    target_link_libraries(SeedWidget ${VTK_LIBRARIES})

### 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.