# MatrixMathFilter

VTKExamples/CSharp/Meshes/MatrixMathFilter

### Description

A tutorial on how to setup a Windows Forms Application utilizing ActiViz.NET can be found here: Setup a Windows Forms Application to use ActiViz.NET

### Code

MatrixMathFilter.cs

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Diagnostics;

    using Kitware.VTK;

    namespace ActiViz.Examples {
       public partial class Form1 : Form {
          public Form1() {
             InitializeComponent();
          }

          private void renderWindowControl1_Load(object sender, EventArgs e) {
             try {
                MatrixMathFilter();
             }
             catch(Exception ex) {
                MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK);
             }
          }

          private void MatrixMathFilter() {
             // Path to vtk data must be set as an environment variable
             // VTK_DATA_ROOT = "C:\VTK\vtkdata-5.8.0"
             vtkTesting test = vtkTesting.New();
             string root = test.GetDataRoot();
             string filePath = System.IO.Path.Combine(root, @"Data\tensors.vtk");
             vtkUnstructuredGridReader reader = vtkUnstructuredGridReader.New();
             reader.SetFileName(filePath);
             reader.Update();

             vtkDataSetSurfaceFilter surfaceFilter = vtkDataSetSurfaceFilter.New();
             surfaceFilter.SetInputConnection(reader.GetOutputPort());
             surfaceFilter.Update();

             vtkMatrixMathFilter matrixMathFilter = vtkMatrixMathFilter.New();
             //matrixMathFilter.SetOperationToDeterminant();
             matrixMathFilter.SetOperationToEigenvalue();
             matrixMathFilter.SetInputConnection(surfaceFilter.GetOutputPort());
             matrixMathFilter.Update();
             matrixMathFilter.GetOutput().GetPointData().SetActiveScalars("Eigenvalue");

             vtkXMLPolyDataWriter writer = vtkXMLPolyDataWriter.New();
             writer.SetInputConnection(matrixMathFilter.GetOutputPort());
             writer.SetFileName(System.IO.Path.Combine(root, @"Data\output.vtp"));
             writer.Write();

             vtkPolyDataMapper mapper = vtkPolyDataMapper.New();
             mapper.SetInputConnection(matrixMathFilter.GetOutputPort());

             // actor
             vtkActor actor = vtkActor.New();
             actor.SetMapper(mapper);
             // get a reference to the renderwindow of our renderWindowControl1
             vtkRenderWindow renderWindow = renderWindowControl1.RenderWindow;
             // renderer
             vtkRenderer renderer = renderWindow.GetRenderers().GetFirstRenderer();
             // set background color
             renderer.SetBackground(0.2, 0.3, 0.4);
             // add our actor to the renderer
             renderer.AddActor(actor);
          }
       }
    }