Desktop : OpenCV Gui Change Alpha and Gamma Value

<H5></h5>
Change gamma or alpha value of a image.

```OpenCV_BrightnessUseAddWeighted.java
import java.awt.EventQueue;
import java.awt.image.BufferedImage;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

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

public class OpenCV_BrightnessUseAddWeighted {
	static {
		System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
	}
	
	private JFrame frmjavaSwing;
	double alpha = 1.0;
	double gamma =1;
	

	public static void main(String[] args) {
		
		EventQueue.invokeLater(new Runnable() {
			
			@Override
			public void run() {
				try {
					OpenCV_BrightnessUseAddWeighted window = new OpenCV_BrightnessUseAddWeighted();
					window.frmjavaSwing.setVisible(true);		
				}catch (Exception e) {
					e.printStackTrace();
				}
				
			}
		});
	}
	
	public OpenCV_BrightnessUseAddWeighted() {
		initialize();
	}
	
	private void initialize() {
		final Mat source = Imgcodecs.imread("D:\\projects\\Java\\OpenCV_Samples\\resource\\imgs\\clean.jpg");
		
		BufferedImage image=matToBufferedImage(merge(source,source,alpha,gamma));
		
		frmjavaSwing = new JFrame();
		frmjavaSwing.setTitle("opencv ���G�׽m��");
		frmjavaSwing.setBounds(100, 100, 520, 550);
		frmjavaSwing.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frmjavaSwing.getContentPane().setLayout(null);
		
		final JLabel showAlphaValue = new JLabel("1.0");
		showAlphaValue.setBounds(260, 10, 29, 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_Gamma = new JSlider();
		slider_Gamma.setMaximum(200);
		slider_Gamma.setValue(0);
		slider_Gamma.setBounds(57, 45, 115, 25);
		frmjavaSwing.getContentPane().add(slider_Gamma);
		
		
		final JSlider slider_Alpha = new JSlider();
		slider_Alpha.setMinimum(10);
		slider_Alpha.setMaximum(50);
		slider_Alpha.setValue(10);
		slider_Alpha.addChangeListener(new ChangeListener() {
			public void stateChanged(ChangeEvent arg0) {
				//System.out.println(slider_Alpha.getValue()/10);
				showAlphaValue.setText((float)slider_Alpha.getValue()/10+"");
				BufferedImage newImage=matToBufferedImage(merge(source,source,(float)slider_Alpha.getValue()/10,slider_Gamma.getValue()));
				lblNewLabel.setIcon(new ImageIcon(newImage));
			}
		});
		slider_Alpha.setBounds(57, 10, 200, 25);
		frmjavaSwing.getContentPane().add(slider_Alpha);
		
		JLabel lblAlpha = new JLabel("Alpha");
		lblAlpha.setBounds(10, 20, 46, 15);
		frmjavaSwing.getContentPane().add(lblAlpha);
		
		JLabel lblGamma = new JLabel("Gamma");
		lblGamma.setBounds(10, 43, 46, 15);
		frmjavaSwing.getContentPane().add(lblGamma);
		
		final JLabel showTypeValue = new JLabel("0");
		showTypeValue.setBounds(182, 45, 19, 15);
		frmjavaSwing.getContentPane().add(showTypeValue);
		
		slider_Gamma.addChangeListener(new ChangeListener() {
			public void stateChanged(ChangeEvent arg0) {
				showTypeValue.setText(slider_Gamma.getValue()+"");
				BufferedImage newImage=matToBufferedImage(merge(source,source,(float)slider_Alpha.getValue()/10,slider_Gamma.getValue()));
				lblNewLabel.setIcon(new ImageIcon(newImage));
				
			}
		});
	}
	
	public Mat merge(Mat source1,Mat source2,double alpha,double gamma){
		
		 Mat destination=new Mat(source1.rows(),source1.cols(),source1.type());
		 Core.addWeighted(source1, alpha, source2, 0, gamma, destination);
		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_ch_alpha_gamma.JPG](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/276243/51896e61-c803-d81e-9865-2f57638b6da6.jpeg)