content: import java.awt.BorderLayout;
  import java.awt.Container;
  import java.awt.Image;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  
  import javax.swing.BoxLayout;
  import javax.swing.ImageIcon;
  import javax.swing.JComboBox;
  import javax.swing.JFrame;
  import javax.swing.JLabel;
  import javax.swing.JPanel;
  import javax.swing.JSlider;
  import javax.swing.event.ChangeEvent;
  import javax.swing.event.ChangeListener;
  
  import org.opencv.core.Core;
  import org.opencv.core.Mat;
  import org.opencv.core.Point;
  import org.opencv.core.Size;
  import org.opencv.highgui.HighGui;
  import org.opencv.imgcodecs.Imgcodecs;
  import org.opencv.imgproc.Imgproc;
  
  public class MorphologyDemo1 {
      private static final String[] ELEMENT_TYPE = { "Rectangle", "Cross", "Ellipse" };
      private static final String[] MORPH_OP = { "Erosion", "Dilatation" };
      private static final int MAX_KERNEL_SIZE = 21;
      private Mat matImgSrc;
      private Mat matImgDst = new Mat();
      private int elementType = Imgproc.CV_SHAPE_RECT;
      private int kernelSize = 0;
      private boolean doErosion = true;
      private JFrame frame;
      private JLabel imgLabel;
  
      //! [constructor]
      public MorphologyDemo1(String[] args) {
          String imagePath = args.length > 0 ? args[0] : "../data/LinuxLogo.jpg";
          matImgSrc = Imgcodecs.imread(imagePath);
          if (matImgSrc.empty()) {
              System.out.println("Empty image: " + imagePath);
              System.exit(0);
          }
  
          // Create and set up the window.
          frame = new JFrame("Erosion and dilatation demo");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          // Set up the content pane.
          Image img = HighGui.toBufferedImage(matImgSrc);
          addComponentsToPane(frame.getContentPane(), img);
          // Use the content pane's default BorderLayout. No need for
          // setLayout(new BorderLayout());
          // Display the window.
          frame.pack();
          frame.setVisible(true);
      }
      //! [constructor]
  
      //! [components]
      private void addComponentsToPane(Container pane, Image img) {
          if (!(pane.getLayout() instanceof BorderLayout)) {
              pane.add(new JLabel("Container doesn't use BorderLayout!"));
              return;
          }
  
          JPanel sliderPanel = new JPanel();
          sliderPanel.setLayout(new BoxLayout(sliderPanel, BoxLayout.PAGE_AXIS));
  
          JComboBox<String> elementTypeBox = new JComboBox<>(ELEMENT_TYPE);
          elementTypeBox.addActionListener(new ActionListener() {
              @Override
              public void actionPerformed(ActionEvent e) {
                  @SuppressWarnings("unchecked")
                  JComboBox<String> cb = (JComboBox<String>)e.getSource();
                  if (cb.getSelectedIndex() == 0) {
                      elementType = Imgproc.CV_SHAPE_RECT;
                  } else if (cb.getSelectedIndex() == 1) {
                      elementType = Imgproc.CV_SHAPE_CROSS;
                  } else if (cb.getSelectedIndex() == 2) {
                      elementType = Imgproc.CV_SHAPE_ELLIPSE;
                  }
                  update();
              }
          });
          sliderPanel.add(elementTypeBox);
  
          sliderPanel.add(new JLabel("Kernel size: 2n + 1"));
          JSlider slider = new JSlider(0, MAX_KERNEL_SIZE, 0);
          slider.setMajorTickSpacing(5);
          slider.setMinorTickSpacing(5);
          slider.setPaintTicks(true);
          slider.setPaintLabels(true);
          slider.addChangeListener(new ChangeListener() {
              @Override
              public void stateChanged(ChangeEvent e) {
                  JSlider source = (JSlider) e.getSource();
                  kernelSize = source.getValue();
                  update();
              }
          });
          sliderPanel.add(slider);
  
          JComboBox<String> morphOpBox = new JComboBox<>(MORPH_OP);
          morphOpBox.addActionListener(new ActionListener() {
              @Override
              public void actionPerformed(ActionEvent e) {
                  @SuppressWarnings("unchecked")
                  JComboBox<String> cb = (JComboBox<String>)e.getSource();
                  doErosion = cb.getSelectedIndex() == 0;
                  update();
              }
          });
          sliderPanel.add(morphOpBox);
  
          pane.add(sliderPanel, BorderLayout.PAGE_START);
          imgLabel = new JLabel(new ImageIcon(img));
          pane.add(imgLabel, BorderLayout.CENTER);
      }
      //! [components]
  
      //! [update]
      private void update() {
          //! [kernel]
          Mat element = Imgproc.getStructuringElement(elementType, new Size(2 * kernelSize + 1, 2 * kernelSize + 1),
                  new Point(kernelSize, kernelSize));
          //! [kernel]
  
          if (doErosion) {
              //! [erosion]
              Imgproc.erode(matImgSrc, matImgDst, element);
              //! [erosion]
          } else {
              //! [dilation]
              Imgproc.dilate(matImgSrc, matImgDst, element);
              //! [dilation]
          }
          Image img = HighGui.toBufferedImage(matImgDst);
          imgLabel.setIcon(new ImageIcon(img));
          frame.repaint();
      }
      //! [update]
  
      //! [main]
      public static void main(String[] args) {
          // Load the native OpenCV library
          System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
  
          // Schedule a job for the event dispatch thread:
          // creating and showing this application's GUI.
          javax.swing.SwingUtilities.invokeLater(new Runnable() {
              @Override
              public void run() {
                  new MorphologyDemo1(args);
              }
          });
      }
      //! [main]
  }
  