initial commit

samples/java/tutorial_code/ImgTrans/canny_detector/CannyDetectorDemo.java

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+import java.awt.BorderLayout;
+import java.awt.Container;
+import java.awt.Image;
+
+import javax.swing.BoxLayout;
+import javax.swing.ImageIcon;
+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.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.Scalar;
+import org.opencv.core.Size;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+public class CannyDetectorDemo {
+    private static final int MAX_LOW_THRESHOLD = 100;
+    private static final int RATIO = 3;
+    private static final int KERNEL_SIZE = 3;
+    private static final Size BLUR_SIZE = new Size(3,3);
+    private int lowThresh = 0;
+    private Mat src;
+    private Mat srcBlur = new Mat();
+    private Mat detectedEdges = new Mat();
+    private Mat dst = new Mat();
+    private JFrame frame;
+    private JLabel imgLabel;
+
+    public CannyDetectorDemo(String[] args) {
+        String imagePath = args.length > 0 ? args[0] : "../data/fruits.jpg";
+        src = Imgcodecs.imread(imagePath);
+        if (src.empty()) {
+            System.out.println("Empty image: " + imagePath);
+            System.exit(0);
+        }
+
+        // Create and set up the window.
+        frame = new JFrame("Edge Map (Canny detector demo)");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        // Set up the content pane.
+        Image img = HighGui.toBufferedImage(src);
+        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);
+    }
+
+    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));
+
+        sliderPanel.add(new JLabel("Min Threshold:"));
+        JSlider slider = new JSlider(0, MAX_LOW_THRESHOLD, 0);
+        slider.setMajorTickSpacing(10);
+        slider.setMinorTickSpacing(5);
+        slider.setPaintTicks(true);
+        slider.setPaintLabels(true);
+        slider.addChangeListener(new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                JSlider source = (JSlider) e.getSource();
+                lowThresh = source.getValue();
+                update();
+            }
+        });
+        sliderPanel.add(slider);
+
+        pane.add(sliderPanel, BorderLayout.PAGE_START);
+        imgLabel = new JLabel(new ImageIcon(img));
+        pane.add(imgLabel, BorderLayout.CENTER);
+    }
+
+    private void update() {
+        Imgproc.blur(src, srcBlur, BLUR_SIZE);
+        Imgproc.Canny(srcBlur, detectedEdges, lowThresh, lowThresh * RATIO, KERNEL_SIZE, false);
+        dst = new Mat(src.size(), CvType.CV_8UC3, Scalar.all(0));
+        src.copyTo(dst, detectedEdges);
+        Image img = HighGui.toBufferedImage(dst);
+        imgLabel.setIcon(new ImageIcon(img));
+        frame.repaint();
+    }
+
+    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 CannyDetectorDemo(args);
+            }
+        });
+    }
+}