Desktop : OpenCV Rotate Use Remap

<h5>Goal</h5>
Roatate a image with remap.

```OpenCV_Rotate_Use_Remap.java
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

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

public class OpenCV_Rotate_Use_Remap {

    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_Rotate_Use_Remap window = new OpenCV_Rotate_Use_Remap();
                    window.frmjavaSwing.setVisible(true);
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        });
    }

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

    /**
     *  Initialize the contents of the frame.
     */
    private void init(){
        final Mat source = Imgcodecs.imread("D:\\projects\\Java\\OpenCV_Samples\\resource\\imgs\\clean.jpg");
        Mat destination=new Mat(source.rows(),source.cols(),source.type());

        BufferedImage image=matToBufferedImage(source);

        frmjavaSwing = new JFrame();
        frmjavaSwing.setTitle("opencv翻轉練習");
        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(source,2));
                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(source,1));
                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(source,3));
                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());
        Mat map_x=new Mat(source.rows(),source.cols(),CvType.CV_32FC1);
        Mat map_y=new Mat(source.rows(),source.cols(), CvType.CV_32FC1);

        for(int j=0;j<source.rows();j++){
            for(int i=0;i<source.cols();i++){

                if(direction==1){
                    //上下翻轉
                    map_x.put(j, i,i);
                    map_y.put(j, i,source.rows()-j);
                }else if(direction==2){
                    //左右翻轉
                    map_x.put(j, i,source.cols()-i);
                    map_y.put(j, i,j);
                }else if(direction==3){
                    //上下左右翻轉
                    map_x.put(j, i,source.cols()-i);
                    map_y.put(j, i,source.rows()-j);
                }
            }
        }

        Imgproc.remap(source, destination,  map_x,  map_y, 0);
        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_rotate_use_remap.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/b1dbb0a7-85cd-d19c-3c3a-9c2f5b3e04a8.jpeg)