Desktop : OpenCV Expand

<h5>Goal</h5>
Test OpenCV expand.

```OpenCV_Expand.java
import java.awt.Component;
import java.awt.EventQueue;

import javax.swing.JFrame;
import java.awt.Canvas;

import javax.swing.ImageIcon;
import javax.swing.JColorChooser;
import javax.swing.JPanel;
import javax.swing.JLabel;

import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

import java.awt.event.MouseMotionAdapter;
import java.awt.event.MouseEvent;
import java.awt.Color;
import java.awt.event.MouseAdapter;
import java.awt.image.BufferedImage;
import javax.swing.JButton;
import javax.swing.border.LineBorder;
import javax.swing.JSlider;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;

public class OpenCV_Expand {

    static {System.loadLibrary(Core.NATIVE_LIBRARY_NAME);}
    private JFrame frmOpencv;
    private Mat src = Imgcodecs.imread(
            "D:\\projects\\Java\\OpenCV_Samples\\resource\\imgs\\lena.jpg");
    private Color color;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    OpenCV_Expand window = new OpenCV_Expand();
                    window.frmOpencv.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public OpenCV_Expand() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {



        final BufferedImage image=matToBufferedImage(src);

        frmOpencv = new JFrame();
        frmOpencv.setTitle("opencv 凸透鏡效果練習");
        frmOpencv.getContentPane().setBackground(Color.LIGHT_GRAY);
        frmOpencv.setBounds(100, 100, 547, 627);
        frmOpencv.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frmOpencv.getContentPane().setLayout(null);

        final JLabel lblShowXY = new JLabel("");
        lblShowXY.setBounds(405, 2, 124, 23);
        frmOpencv.getContentPane().add(lblShowXY);


        JPanel panel = new JPanel();

        final JLabel lblPaintLabel = new JLabel("");
        lblPaintLabel.setIcon(new ImageIcon(image));
        panel.add(lblPaintLabel);


        panel.setBounds(10, 64, 519, 519);
        frmOpencv.getContentPane().add(panel);

        JLabel lblNewLabel = new JLabel("強度");
        lblNewLabel.setBounds(10, 20, 58, 15);
        frmOpencv.getContentPane().add(lblNewLabel);

        final JSlider slider = new JSlider();
        slider.setMaximum(300);

        slider.setValue(30);
        slider.setMinimum(1);
        slider.setBounds(78, 10, 200, 25);
        frmOpencv.getContentPane().add(slider);

        final JLabel Label_scale = new JLabel("30");
        Label_scale.setBounds(298, 20, 46, 15);
        frmOpencv.getContentPane().add(Label_scale);

        slider.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent arg0) {
                Label_scale.setText(slider.getValue()+"");
            }
        });

        panel.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent arg0) {
                lblShowXY.setText("X:"+arg0.getX()+",Y:"+arg0.getY());
                BufferedImage newImage=matToBufferedImage(expand(src,slider.getValue(),arg0.getX(),arg0.getY()) );
                lblPaintLabel.setIcon(new ImageIcon(newImage));
            }
        });
    }

    public Mat expand(Mat source,int Scale,int PntX,int PntY){
        Point pt=new Point(PntX,PntY);
        Mat destination=new Mat(source.rows(),source.cols(),source.type());
        source.copyTo(destination);
        for (int y=0;y<source.height();y++){

            for(int x=0;x<source.width();x++){

                int dist=(int)getDistance(new Point(x,y),pt);
                if(dist<Scale){
                    int newX=(int) (((x-pt.x)*dist/Scale)+pt.x);
                    int newY=(int) (((y-pt.y)*dist/Scale)+pt.y);
                    double[] temp=source.get(newY,newX*2);
                    double[] temp1=source.get(newY,newX*2+1);
                    double[] temp2=source.get(newY,newX*2+2);

                    if (temp!=null){
                        destination.put(y,2*x,temp);
                    }
                    if (temp1!=null){
                        destination.put(y,2*x+1,temp1);
                    }
                    if (temp2!=null){
                        destination.put(y,2*x+2,temp2);
                    }
                }
            }
        }
        return destination;
    }
    public static double getDistance(Point a,Point b){
        return Math.sqrt(Math.pow(a.x-b.x, 2)+Math.pow(a.y-b.y, 2));
    }

    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;
    }

    public Color getColor() {
        return color;
    }

    public void setColor(Color color) {
        this.color = color;
    }
}
```
<h5>Result</h5>
![opencv_expand.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/e5d1bc62-d45e-2bef-9a97-88d19c9106c8.jpeg)