Desktop : Opencv webcam preview

import javax.swing.JFrame;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.videoio.VideoCapture;

public class OpenCV_webcam3 {

    static {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    }

    public static void main(String[] args) {

        VideoCapture camera = null;
        camera =  initWebcam();
        JFrame frame1 = new JFrame("Show image");
        frame1.setTitle("從 webcam 讀取影像到 Java swing 視窗");
        frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame1.setSize(640, 480);
        frame1.setBounds(0,0,frame1.getWidth(),frame1.getHeight());
        Panel panel1 = new Panel();
        frame1.setContentPane(panel1);
        frame1.setVisible(true);

        if(camera.isOpened()) {
            Mat webcam_frame = new Mat();
            camera.read(webcam_frame);
            frame1.setSize(webcam_frame.width(),webcam_frame.height());

            while (true) {
                camera.read(webcam_frame);
                panel1.setimagewithMat(webcam_frame);
                frame1.repaint();
            }

        }else {
            System.out.print("Error");
        }

    }


    private static VideoCapture initWebcam() {
        VideoCapture cameraCapture = new VideoCapture();
        cameraCapture.open(0);

        return cameraCapture;
    }
}