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我的问题是我拍摄了一张图像，然后我更改了一些像素值，然后将它们设置到所需的位置，然后我写入图像，然后我使用 ImageIO.read() 通过使用图像对象读取图像我没有得到以前的值.. .那么我怎样才能得到以前的值

import java.awt.*;

import java.awt.event.*;

import java.awt.image.*;

import java.io.*;

import javax.imageio.*;

import javax.swing.*;


public class LoadImageApp extends JFrame implements ActionListener

{

      BufferedImage img=null;
  BufferedImage img1=null;
  BufferedImage mask=null;
  BufferedImage rao=null;
      JButton b1;
  int pixel[][];
  int w,h;
  JFileChooser chooser;
  File file;
      public void paint(Graphics g)
      {
         g.drawImage(img,50,50,150,200,this);
     g.drawImage(mask,600,100,150,200,this);

      }

  public LoadImageApp()
      {  
         super("Image...");
     setSize(800,800);
     setLayout(new FlowLayout());
     b1=new JButton("Select Image");
     b1.setSize(250,20);
     add(b1);
     b1.addActionListener(this);
     setVisible(true);
      }
  public void actionPerformed(ActionEvent ae)
  {
     try
     {  

                    chooser = new JFileChooser("C:/Users/Ravi/Desktop");
            chooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
                int returnVal = chooser.showOpenDialog(this);
                if(returnVal == JFileChooser.APPROVE_OPTION) 
            {
             file=chooser.getSelectedFile();
             img=ImageIO.read(file);
             mask=new BufferedImage(img.getWidth(),img.getHeight(),img.getType());
             repaint();
             img1=img.getSubimage(0,0,100,150);
                }
            repaint();
            pixel=getPixels(img);
            int i=80,j=50;
            int temp[]={1,1,1,1};
            int temp1=setPixel(temp);
            for(j=0;j<w;j++)
             pixel[i][j]=temp1;
            System.out.println("pixels before.."+pixel[80][3]);
            this.setPixels();//setting pixels....
            ImageIO.write(mask,"jpeg",new File("aft-con.jpeg"));//write the image

           BufferedImage next=ImageIO.read(new File("aft-con.jpeg"));
           ord=getPixels(next);//getting the previous values...
           org=getARGB(ord[80][3]);
           System.out.println("pixels before.."+pixel[80][3]);//but it is not same...

         }
         catch(Exception e)
         {
            System.out.println("error in action");
         }
   }
   public int setPixel(int rgb[])
   {
        int pixel = (((rgb[0] & 0x0ff)<<24)|((rgb[1] & 0x0ff)<<16)|((rgb[2] & 0x0ff)<<8)|(rgb[3] & 0x0ff));
        return pixel;
   }
   public int[] getARGB(int pixel)
   {
          int rgb[]=new int[4];
          rgb[0] =((pixel >> 24) & 0xff);
          rgb[1] = ((pixel >> 16) & 0xff);
          rgb[2] =((pixel >> 8) & 0xff);
          rgb[3] =((pixel ) & 0xff);

           return rgb;
    }

    public int[][] getPixels(BufferedImage img)
   { 
      w=img.getWidth();
      h=img.getHeight();
      int pixels[][]=new int[h][w];

     int i=0,j=0;
     try
     {
       for(i=0;i<h;i++)
        for(j=0;j<w;j++)
            pixels[i][j]=img.getRGB(j,i);

     }
     catch(Exception e)
     {
         System.out.println("i:"+i+" j:"+j);
     }


     return pixels;
 }
 public void setPixels()
 {
      w=img.getWidth();
      h=img.getHeight();

          int i=0,j=0;
      try
      {
       for(i=0;i<h;i++)
         for(j=0;j<w;j++)
         mask.setRGB(j,i,pixel[i][j]);
      }
      catch(Exception e)
      {
                System.out.println("error at setting pixel");
      }
 }

     public static void main(String[] args) 
     {

        LoadImageApp f = new LoadImageApp();
            f.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e) {
            System.exit(0);
             }
           });
    }

}

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1 回答 1

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当图像保存为 JPEG 时，它会被压缩。这会导致像素值发生变化。如果您不希望发生任何更改，则需要以无损格式保存，例如 PNG。

于 2013-03-16T22:00:32.570 回答