使用JSlider更改图像后刷新图像

Question

我有一个程序，将改变阈值在img，但我不知道如何刷新图像。它将创建两个JFrame窗口，一个用于滑动条，一个用于图像。我确实从滑块中获取value去到threshold。但是我如何刷新改变的图像。对不起，张贴整个代码，但我不能弄清楚这个

import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import java.awt.image.BufferedImage;
import  java.awt.image.DataBufferByte;
import java.lang.Math;
import java.util.ArrayList;
import java.util.List;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.Size;
import org.opencv.core.MatOfPoint;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;
import org.opencv.core.CvType;
import org.opencv.core.MatOfDouble;
public class Draw extends JFrame{
    JSlider slider;
    JLabel label;
    JLabel test1;
    int Actual;
    int value = 100;
    public Draw(){
        setLayout(new FlowLayout());
        slider = new JSlider(JSlider.HORIZONTAL, 0, 255, 100);
        add(slider);
        label = new JLabel();
        add(label);
        test1 = new JLabel();
        add(test1);
        event e = new event();
        slider.addChangeListener(e);


    }
     public class event implements ChangeListener {
         public void stateChanged(ChangeEvent e){
              value = slider.getValue();
              label.setText("Current Value " + value);

         }
     }

     public static void main(String agrs[]){
         System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
         Draw sl = new Draw();
         sl.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         sl.setSize(300,100);
         sl.setVisible(true);
         sl.setTitle("Slider Bar");
         sl.converter();
         sl.repaint();
         sl.revalidate();

     }
 public void converter(){

         Mat imageInMat = Imgcodecs.imread("C:/Users/ja/workspace/imgtomath/bin/imgtomath/bowl.jpg",0);
         if(imageInMat.empty()== true)
             {System.out.println("Error no image found!!");}
         else
             System.out.println("Image loaded");

         Mat thresh = new Mat();
        Imgproc.threshold(imageInMat, thresh, value, 250, Imgproc.THRESH_BINARY_INV);
        BufferedImage bufImage = Mat2BufferedImage(thresh); 
        displayImage(bufImage); 
        }
 public BufferedImage Mat2BufferedImage(Mat m){
        //source: http://answers.opencv.org/question/10344/opencv-java-load-image-to-gui/
        //Fastest code
        //The output can be assigned either to a BufferedImage or to an Image
         int type = BufferedImage.TYPE_BYTE_GRAY;
         if ( m.channels() > 1 ) {
             type = BufferedImage.TYPE_3BYTE_BGR;
         }
         int bufferSize = m.channels()*m.cols()*m.rows();
         byte [] b = new byte[bufferSize];
         m.get(0,0,b); // get all the pixels
         BufferedImage image = new BufferedImage(m.cols(),m.rows(), type);
         final byte[] targetPixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
         System.arraycopy(b, 0, targetPixels, 0, b.length);  
         return image;
        }
 public void displayImage(Image img2)
    {   
    //BufferedImage img=ImageIO.read(new File("/HelloOpenCV/lena.png"));
    ImageIcon icon=new ImageIcon(img2);
    JFrame frame=new JFrame();
    frame.setLayout(new FlowLayout());  
    frame.setSize(img2.getWidth(null)+50, img2.getHeight(null)+50);     
    JLabel lbl=new JLabel();
    lbl.setIcon(icon);  
    frame.add(lbl);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}


}

Answer 1

我理解的问题是，如果你从stateChanged()调用converter()，它会创建一个新的JFrame每次你改变滑块上的值?

这里有一个简单的建议来防止这种情况:

stateChanged:

public void stateChanged(ChangeEvent e){
  value = slider.getValue();
  label.setText("Current Value " + value);
  converter();
}

displayImage:

 private JFrame frame = new JFrame("Image JFrame");
 JLabel lbl = null;
 public void displayImage(Image img2){   
    if(lbl==null){
       lbl = new JLabel();
       frame.setLayout(new FlowLayout());    
       frame.setSize(img2.getWidth(null)+50, img2.getHeight(null)+50);     
       frame.add(lbl);
       frame.setVisible(true);
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    ImageIcon icon=new ImageIcon(img2);
    lbl.setIcon(icon);  
}

还有:您应该从您的主方法在Event线程上创建Swing组件，如https://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html