Desktop : OpenCV Flip image

<h5>Goal</h5>
Test OpenCV flip a image.

```java:OpenCV_RotateUseFlip.java

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;

public class OpenCV_RotateUseFlip {

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

    private JFrame frmjavaSwing;

    /**
     *  Launch the application.
     */

    public static void main(String[] args){
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try{
                    OpenCV_RotateUseFlip window = new OpenCV_RotateUseFlip();
                    window.frmjavaSwing.setVisible(true);
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     *  Create the application.
     */
    public OpenCV_RotateUseFlip(){
        init();
    }

    public void init(){
        final Mat src = Imgcodecs.imread("D:\\projects\\Java\\OpenCV_Samples\\resource\\imgs\\clean.jpg");
        Mat dst = new Mat(src.rows(),src.cols(),src.type());

        BufferedImage image  = matToBufferedImage(src);

        frmjavaSwing = new JFrame();
        frmjavaSwing.setTitle("opencv翻轉練習2,使用Core.flip");
        frmjavaSwing.setBounds(100, 100, 560, 620);
        frmjavaSwing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frmjavaSwing.getContentPane().setLayout(null);

        final JLabel lblNewLabel = new JLabel("");
        lblNewLabel.setBounds(5, 60, image.getHeight()+10, image.getWidth()+10);
        lblNewLabel.setIcon(new ImageIcon(image));
        frmjavaSwing.getContentPane().add(lblNewLabel);

        JButton btnX = new JButton("水平翻轉");
        btnX.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(chgDirection(src,1));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnX.setBounds(30, 10, 87, 23);
        frmjavaSwing.getContentPane().add(btnX);

        JButton btnNewButton = new JButton("垂直翻轉");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(chgDirection(src,0));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnNewButton.setBounds(178, 10, 87, 23);
        frmjavaSwing.getContentPane().add(btnNewButton);

        JButton btnNewButton_1 = new JButton("水平及垂直翻轉");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                BufferedImage newImage=matToBufferedImage(chgDirection(src,-1));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        btnNewButton_1.setBounds(316, 10, 134, 23);
        frmjavaSwing.getContentPane().add(btnNewButton_1);

    }

    public Mat chgDirection(Mat source,int direction){

        Mat destination=new Mat(source.rows(),source.cols(),source.type());
        Core.flip(source, destination, direction);
        return destination;
    }

    public BufferedImage matToBufferedImage(Mat matrix) {
        int cols = matrix.cols();
        int rows = matrix.rows();
        int elemSize = (int)matrix.elemSize();
        byte[] data = new byte[cols * rows * elemSize];
        int type;
        matrix.get(0, 0, data);
        switch (matrix.channels()) {
            case 1:
                type = BufferedImage.TYPE_BYTE_GRAY;
                break;
            case 3:
                type = BufferedImage.TYPE_3BYTE_BGR;
                // bgr to rgb
                byte b;
                for(int i=0; i<data.length; i=i+3) {
                    b = data[i];
                    data[i] = data[i+2];
                    data[i+2] = b;
                }
                break;
            default:
                return null;
        }
        BufferedImage image2 = new BufferedImage(cols, rows, type);
        image2.getRaster().setDataElements(0, 0, cols, rows, data);
        return image2;
    }
}
```

<h5>Result</h5>
![opencv_filp.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/7f062fdb-e295-e50b-4129-6ff44176a7e5.jpeg)