# LogoWidget

VTKExamples/Cxx/Widgets/LogoWidget

### Description

Turn the widget on before the render. Otherwise, it won't appear until you interact with the scene.

### Code

LogoWidget.cxx

    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkImageCanvasSource2D.h>
    #include <vtkLogoRepresentation.h>
    #include <vtkLogoWidget.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty2D.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSphereSource.h>
    #include <vtkSphereSource.h>

    int main(int, char *[])
    {
      // A sphere
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->SetCenter(0.0, 0.0, 0.0);
      sphereSource->SetRadius(4.0);
      sphereSource->SetPhiResolution(4);
      sphereSource->SetThetaResolution(8);
      sphereSource->Update();

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

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

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

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

      // Create an image
      vtkSmartPointer<vtkImageCanvasSource2D> drawing =
        vtkSmartPointer<vtkImageCanvasSource2D>::New();
      drawing->SetScalarTypeToUnsignedChar();
      drawing->SetNumberOfScalarComponents(3);
      drawing->SetExtent(0,200,0,200,0,0);

      // Clear the image
      drawing->SetDrawColor(255, 127, 100);
      drawing->FillBox(0,200,0,200);
      drawing->SetDrawColor(0, 0, 0);
      drawing->DrawCircle(100, 100, 50);
      drawing->Update();

      vtkSmartPointer<vtkLogoRepresentation> logoRepresentation =
        vtkSmartPointer<vtkLogoRepresentation>::New();
      logoRepresentation->SetImage(drawing->GetOutput());
      logoRepresentation->SetPosition(0,0);
      logoRepresentation->SetPosition2(.4, .4);
      logoRepresentation->GetImageProperty()->SetOpacity(.7);

      vtkSmartPointer<vtkLogoWidget> logoWidget =
        vtkSmartPointer<vtkLogoWidget>::New();
      logoWidget->SetInteractor(renderWindowInteractor);
      logoWidget->SetRepresentation(logoRepresentation);

      renderWindow->Render();
      logoWidget->On();
      renderer->SetBackground(.2, .3, .4);
      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(LogoWidget)

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

    add_executable(LogoWidget MACOSX_BUNDLE LogoWidget.cxx)

    target_link_libraries(LogoWidget ${VTK_LIBRARIES})

### Download and Build LogoWidget

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

    cd LogoWidget/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:

    ./LogoWidget

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