Desktop : OpenCV Color Map

<H5>Goal</H5>
Test OpenCV Color Map.

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

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.awt.*;
import java.awt.image.BufferedImage;

public class OpenCV_Apply_Color_Map {
    static {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    }

    private JFrame frmjavaSwing;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    OpenCV_Apply_Color_Map window = new OpenCV_Apply_Color_Map();
                    window.frmjavaSwing.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public OpenCV_Apply_Color_Map() {
        initialize();
        System.out.println( "Imgproc.COLORMAP_AUTUMN="+Imgproc.COLORMAP_AUTUMN);
        System.out.println( "Imgproc.COLORMAP_BONE="+Imgproc.COLORMAP_BONE);
        System.out.println( "Imgproc.COLORMAP_COOL="+Imgproc.COLORMAP_COOL);
        System.out.println( "Imgproc.COLORMAP_HOT="+Imgproc.COLORMAP_HOT);
        System.out.println( "Imgproc.COLORMAP_HSV="+Imgproc.COLORMAP_HSV);
        System.out.println( "Imgproc.COLORMAP_JET="+Imgproc.COLORMAP_JET);
        System.out.println( "Imgproc.COLORMAP_OCEAN="+Imgproc.COLORMAP_OCEAN);
        System.out.println( "Imgproc.COLORMAP_PARULA="+Imgproc.COLORMAP_PARULA);
        System.out.println( "Imgproc.COLORMAP_PINK="+Imgproc.COLORMAP_PINK);
        System.out.println( "Imgproc.COLORMAP_RAINBOW="+Imgproc.COLORMAP_RAINBOW);
        System.out.println( "Imgproc.COLORMAP_SPRING="+Imgproc.COLORMAP_SPRING);
        System.out.println( "Imgproc.COLORMAP_SUMMER="+Imgproc.COLORMAP_SUMMER);
        System.out.println( "Imgproc.COLORMAP_WINTER="+ Imgproc.COLORMAP_WINTER);
    }

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

        //BufferedImage image=matToBufferedImage(applyColorMap(source,alpha));

        frmjavaSwing = new JFrame();
        frmjavaSwing.setTitle("讀取影像至Java Swing視窗");
        frmjavaSwing.setBounds(100, 100, 520, 550);
        frmjavaSwing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frmjavaSwing.getContentPane().setLayout(null);

        final JLabel showAlphaValue = new JLabel("2");
        showAlphaValue.setBounds(311, 20, 46, 15);
        frmjavaSwing.getContentPane().add(showAlphaValue);

        final JLabel lblNewLabel = new JLabel("");
        lblNewLabel.setBounds(10, 68, 438, 438);
        //lblNewLabel.setIcon(new ImageIcon(image));
        frmjavaSwing.getContentPane().add(lblNewLabel);

        final JSlider slider_alpha = new JSlider();
        slider_alpha.setMaximum(12);
        slider_alpha.setValue(2);
        slider_alpha.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent arg0) {
                //System.out.println(slider_alpha.getValue());
                showAlphaValue.setText(slider_alpha.getValue()+"");
                BufferedImage newImage=matToBufferedImage(applyColorMap(source,slider_alpha.getValue()));
                lblNewLabel.setIcon(new ImageIcon(newImage));
            }
        });
        slider_alpha.setBounds(101, 10, 200, 25);
        frmjavaSwing.getContentPane().add(slider_alpha);

        JLabel lblAlpha = new JLabel("ColorMap");

        lblAlpha.setBounds(10, 20, 92, 15);
        frmjavaSwing.getContentPane().add(lblAlpha);

    }
    public Mat applyColorMap(Mat source,int colormap){

        Mat destination=new Mat(source.rows(),source.cols(),source.type());
        Imgproc.applyColorMap(source, destination, colormap);

        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_color_map.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/a4f056e4-8f0b-c148-ca57-7d5651922750.jpeg)