# ClipArt

VTKExamples/Cxx/Visualization/ClipArt

### Description

This is an adaptation of the VTK test clipArt.tcl. Provide a jpg file with 2D clipart and the example will create 3D polydata model. The examples illustrates a number of VTK classes including vtkImageThreshold, vtkImageSeedConnectivity, vtkDecimatePro and vtkClipPolyData.

The example assumes that the image has a white background. Try it with this input data.

### Code

ClipArt.cxx

    #include <vtkVersion.h>
    #include <vtkSmartPointer.h>

    #include <vtkActor.h>
    #include <vtkCamera.h>
    #include <vtkClipPolyData.h>
    #include <vtkDecimatePro.h>
    #include <vtkImageConstantPad.h>
    #include <vtkImageData.h>
    #include <vtkImageDataGeometryFilter.h>
    #include <vtkImageExtractComponents.h>
    #include <vtkImageGaussianSmooth.h>
    #include <vtkImageRGBToHSV.h>
    #include <vtkImageSeedConnectivity.h>
    #include <vtkImageShrink3D.h>
    #include <vtkImageThreshold.h>
    #include <vtkLinearExtrusionFilter.h>
    #include <vtkPointData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkJPEGReader.h>
    #include <vtkTexture.h>
    #include <vtkTextureMapToPlane.h>
    #include <vtkTriangleFilter.h>

    #include <vtkInformation.h>
    #include <vtkStreamingDemandDrivenPipeline.h>

    int main (int argc, char *argv[])
    {
      if (argc < 2)
      {
        std::cout << "Usage: " << argv[0]
                  << " Filename(.jpg)" << std::endl;
        return EXIT_FAILURE;
      }

      vtkSmartPointer<vtkJPEGReader> imageIn =
        vtkSmartPointer<vtkJPEGReader>::New();
      imageIn->SetFileName(argv[1]);

      // Convert the image to hsv so that we can threshold on value
      vtkSmartPointer<vtkImageRGBToHSV> toHSV =
        vtkSmartPointer<vtkImageRGBToHSV>::New();
      toHSV->SetInputConnection(imageIn->GetOutputPort());

      // Just work with the value
      vtkSmartPointer<vtkImageExtractComponents> extractImage =
        vtkSmartPointer<vtkImageExtractComponents>::New();
      extractImage->SetInputConnection(toHSV->GetOutputPort());
      extractImage->SetComponents(2);

      // Threshold to a black/white image
      vtkSmartPointer<vtkImageThreshold> threshold1 =
        vtkSmartPointer<vtkImageThreshold>::New();
      threshold1->SetInputConnection(extractImage->GetOutputPort());
      threshold1->ThresholdByUpper(230);
      threshold1->SetInValue(255);
      threshold1->SetOutValue(0);
      threshold1->Update();

      // Place a seed in each corner and label connected pixels with 255
    #if VTK_MAJOR_VERSION <= 5
      int *extent = threshold1->GetOutput()->GetWholeExtent();
    #else
      threshold1->UpdateInformation();

      int *extent = threshold1->GetOutputInformation(0)->Get(
        vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT());
    #endif
      vtkSmartPointer<vtkImageSeedConnectivity> connect =
        vtkSmartPointer<vtkImageSeedConnectivity>::New();
      connect->SetInputConnection(threshold1->GetOutputPort());
      connect->SetInputConnectValue(255);
      connect->SetOutputConnectedValue(255);
      connect->SetOutputUnconnectedValue(0);
      connect->AddSeed(extent[0], extent[2]);
      connect->AddSeed(extent[1], extent[2]);
      connect->AddSeed(extent[1], extent[3]);
      connect->AddSeed(extent[0], extent[3]);

      // Smooth a little before clipping
      vtkSmartPointer<vtkImageGaussianSmooth> smooth =
        vtkSmartPointer<vtkImageGaussianSmooth>::New();
      smooth->SetDimensionality(2);
      smooth->SetStandardDeviation(1.0, 1.0);
      smooth->SetInputConnection(connect->GetOutputPort());

      vtkSmartPointer<vtkImageShrink3D> shrink =
        vtkSmartPointer<vtkImageShrink3D>::New();
      shrink->SetInputConnection(smooth->GetOutputPort());
      shrink->SetShrinkFactors(1, 1, 1);
      shrink->AveragingOn();

      // Convert the image to polydata
      vtkSmartPointer<vtkImageDataGeometryFilter> geometry =
        vtkSmartPointer<vtkImageDataGeometryFilter>::New();
      geometry->SetInputConnection(shrink->GetOutputPort());

      // Create texture coordinates
      vtkSmartPointer<vtkTextureMapToPlane> geometryTexture =
        vtkSmartPointer<vtkTextureMapToPlane>::New();
      geometryTexture->SetInputConnection(geometry->GetOutputPort());
      geometryTexture->SetOrigin(0, 0, 0);
      geometryTexture->SetPoint1(extent[1], 0, 0);
      geometryTexture->SetPoint2(0, extent[3], 0);

      // Clip the geometry
      vtkSmartPointer<vtkClipPolyData> clip =
        vtkSmartPointer<vtkClipPolyData>::New();
      clip->SetInputConnection(geometryTexture->GetOutputPort());
      clip->SetValue(5.5);
      clip->GenerateClipScalarsOff();
      clip->InsideOutOff();
      clip->InsideOutOn();

      vtkSmartPointer<vtkTriangleFilter> triangles =
        vtkSmartPointer<vtkTriangleFilter>::New();
      triangles->SetInputConnection(clip->GetOutputPort());

      vtkSmartPointer<vtkDecimatePro> decimate =
        vtkSmartPointer<vtkDecimatePro>::New();
      decimate->SetInputConnection(triangles->GetOutputPort());
      decimate->BoundaryVertexDeletionOn();
      decimate->SetDegree(100);
      decimate->PreserveTopologyOn();
      decimate->SetTargetReduction(.99);

      vtkSmartPointer<vtkLinearExtrusionFilter> extrude =
        vtkSmartPointer<vtkLinearExtrusionFilter>::New();
      extrude->SetInputConnection(decimate->GetOutputPort());
      extrude->SetExtrusionTypeToNormalExtrusion();
      extrude->SetScaleFactor(-10);

      vtkSmartPointer<vtkPolyDataMapper> map =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      map->SetInputConnection(extrude->GetOutputPort());
      map->ScalarVisibilityOff();

      vtkSmartPointer<vtkTexture> imageTexture =
        vtkSmartPointer<vtkTexture>::New();
      imageTexture->InterpolateOn();
      imageTexture->SetInputConnection(imageIn->GetOutputPort());

      vtkSmartPointer<vtkActor> clipart =
        vtkSmartPointer<vtkActor>::New();
      clipart->SetMapper(map);
      clipart->SetTexture(imageTexture);

      // Create the RenderWindow, Renderer and Interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

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

      renderer->AddActor(clipart);

      // Create a nice view
      renderer->ResetCamera();
      renderer->GetActiveCamera()->Azimuth(30);
      renderer->GetActiveCamera()->Elevation(30);
      renderer->GetActiveCamera()->Dolly(1.5);
      renderer->ResetCameraClippingRange();

      renderer->SetBackground(0.2, 0.3, 0.4);
      renderWindow->SetSize(320, 256);

      interactor->Initialize();

      renderWindow->Render();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ClipArt)

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

    add_executable(ClipArt MACOSX_BUNDLE ClipArt.cxx)

    target_link_libraries(ClipArt ${VTK_LIBRARIES})

### Download and Build ClipArt

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

    cd ClipArt/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:

    ./ClipArt

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.