# ReadSLC

VTKExamples/Java/IO/ReadSLC

### Description

In this example you will familiarize yourself with the stages required to read a .slc file and create a visualization pipeline in VTK. Following is the three step procedure:

1. Read the data from .slc file using vtkSLCReader

2. Implement Marching cubes Algorithm using vtkContourFilter

3. Create Visualization pipeline to visualize data using an actor, mapper and rendering window

Cite

This example was provided by Bharatesh Chakravarthi from Virtual Environment Lab, Chung-Ang University, Seoul, South Korea

Other Languages

See (Cxx), (Python)

### Code

ReadSLC.java

    import vtk.vtkActor;
    import vtk.vtkNamedColors;
    import vtk.vtkNativeLibrary;
    import vtk.vtkPolyDataMapper;
    import vtk.vtkRenderWindow;
    import vtk.vtkRenderWindowInteractor;
    import vtk.vtkRenderer;
    import vtk.vtkSLCReader;
    import vtk.vtkContourFilter;
    import vtk.vtkOutlineFilter;
    import vtk.vtkExtractVOI;

    public class  ReadSLC
    {
      // -----------------------------------------------------------------
      // Load VTK library and print which library was not properly loaded
      static
      {
        if (!vtkNativeLibrary.LoadAllNativeLibraries())
        {
          for (vtkNativeLibrary lib : vtkNativeLibrary.values())
          {
            if (!lib.IsLoaded())
            {
              System.out.println(lib.GetLibraryName() + " not loaded");
            }
          }
        }
        vtkNativeLibrary.DisableOutputWindow(null);
      }
      // -----------------------------------------------------------------

      public static void main(String args[])
      {
        //parse command line arguments
        if (args.length != 2)
        {
          System.err.println("Usage: java -classpath ... Filename(.slc) e.g vw_knee.slc");
          return;
        }
        String inputFilename = args[0];

        double isoValue = 72.0;
        if (args.length != 2)
        {
          isoValue = 72.0;
        }
        else
        {
          isoValue = Integer.valueOf(args[1]);
        }

        vtkNamedColors colors = new vtkNamedColors();

        //For Actor Color
        double actorColor[] = new double[4];
        //Renderer Background Color
        double Bgcolor[] = new double[4];

        colors.GetColor("Ivory", actorColor);
        colors.GetColor("SlateGray", Bgcolor);

        //Using vtkSLCReader to read Volumetric file format(<filename.slc>)
        vtkSLCReader reader = new vtkSLCReader();
        reader.SetFileName(inputFilename);
        reader.Update();

        // Implementing Marching Cubes Algorithm to create the surface using vtkContourFilter object
        vtkContourFilter cFilter = new vtkContourFilter();
        cFilter.SetInputConnection(reader.GetOutputPort());

        // Change the range(2nd and 3rd Paramater) based on your
        // requirement. recomended value for 1st parameter is above 1
        // cFilter.GenerateValues(5, 80.0, 100.0);
        cFilter.SetValue(0, isoValue);
        cFilter.Update();

        //Adding the outliner using vtkOutlineFilter object
        vtkOutlineFilter outliner = new vtkOutlineFilter();
        outliner.SetInputConnection(reader.GetOutputPort());
        outliner.Update();

        // Visualize
        vtkPolyDataMapper mapper = new vtkPolyDataMapper();
        mapper.SetInputConnection(cFilter.GetOutputPort());
        mapper.SetScalarVisibility(0);

        vtkActor actor = new vtkActor();
        actor.SetMapper(mapper);
        actor.GetProperty().SetDiffuse(.8);
        actor.GetProperty().SetDiffuseColor(actorColor);
        actor.GetProperty().SetSpecular(.8);
        actor.GetProperty().SetSpecularPower(120.0);

        //extractVOI is used to fix the problem of subsampling of data and reduce slow interaction and increase loading speed
        vtkExtractVOI extractVOI = new vtkExtractVOI();
        extractVOI.SetInputConnection(reader.GetOutputPort());
        extractVOI.SetSampleRate(2, 2, 2);
        extractVOI.Update();

        // Create the renderer, render window and interactor.
        vtkRenderer ren = new vtkRenderer();
        vtkRenderWindow renWin = new vtkRenderWindow();
        renWin.AddRenderer(ren);
        vtkRenderWindowInteractor iren = new vtkRenderWindowInteractor();
        iren.SetRenderWindow(renWin);

        // Visualise
        ren.AddActor(actor);

        ren.SetBackground(Bgcolor);

        renWin.SetSize(640, 512);
        renWin.Render();

        iren.Initialize();
        iren.Start();
      }
    }