setting background image on jframe

[jeevansai jinne]

I was trying to set background image for jframe but was not able to do so .Can someone explain mistake in my code.

import java.awt.*;
import javax.swing.*;
import java.io.*;
import java.util.*;
import java.awt.Toolkit.*;
class bg extends JPanel{
Image img;
public bg(){
img = Toolkit.getDefaultToolkit().createImage("background.jpg");
}
public void paintComponent(Graphics g) 
{        
g.drawImage(img,0,0,null);
}        
}       
class test1{
             
public static void main(String args[])
{
JFrame f = new JFrame();
JPanel p = new bg();
f.add(p);
f.setVisible(true); 
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}   
}   

[Paweł Baczyński]

Please, UseCodeTags (this is a link) when posting. I have added them for you this time. Doesn't it look better?

You can try replacing

g.drawImage(img, 0, 0, null);

with

g.drawImage(img, 0, 0, this);

The reason is, the image has not beed loaded when drawImage() is called for the first time. You can verity this by printing the result of this method (it returns false if the image has not been loaded, true otherwise).
Adding the panel as ImageObserver ensures that the image will be drawn when fully loaded.

Also, don't write String args[]. It should be String[] args.

[Campbell Ritchie]

Welcome to the Ranch

Your code would have looked even better with indentation; we have some suggestions here.
I am 99.9% sure that writing .* after Toolkit in the import declaration was a mistake. What do you actually want to import?

[Campbell Ritchie]

I merged your stuff with the following thread. I hope that is okay by you.

[jeevansai jinne]

I was trying to put a image on jpanel but i was gettong a zoomed in image.Can someone tell how to get the actual image as background.
screenshot of output is attached.

    import javax.swing.*;
    import java.awt.*;
    import java.util.*;
    class test1{
    public static void main(String args[])
    {
    JFrame f = new JFrame();
    f.setSize(1800,2880);
    ImageIcon i = new ImageIcon("background.jpg");
    JLabel l = new JLabel();
    l.setIcon(i);
     
    JPanel p = new JPanel();
    p.add(l);
    //JPanel p = new JPanel(new JLabel(new ImageIcon("background.jpg"))); 
    f.add(p);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    }

original image

[Campbell Ritchie]

I think I shall merge your thread with your other one because they are about related subjects.

I am 99% sure that the problem has to do with the size of the image. If you open that image with a photo editor, it will probably say it is 8MB size and 3450×2300px. Now that is larger than most screens. Unlike a photo editor, a Swing component does not zoom automatically. Start by shrinking that image with your photo editor, in which case it will probably occupy little enough space that the whole picture is visible. Not sure what to do to about zooming. You can try adding the panel to a scroll pane. You can try copying the Graphics object with its create() method, casting to Graphics2D and using its scale method. But I am not quite sure how you would code that,

You should also always run Swing code on the Event Dispatch Thread.

[Les Morgan]

Your answer has already been stated, but as I dislike imageIcon, here is another way of doing it:

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;

import java.net.URL;

import javax.swing.JFrame;
import javax.swing.JPanel;

import javax.imageio.ImageIO;

public class JImage{
  BufferedImage bi = null;
  JImage(){
    try{
      bi = ImageIO.read(new URL("http://averweij.web.cern.ch/averweij/d10%5Cd10_07.JPG"));
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      MyJPanel p = new MyJPanel();
      p.setPreferredSize(new Dimension(bi.getWidth(), bi.getHeight()));
      f.add(p);
      f.pack();
      f.setVisible(true);
    }catch(Exception e){
      e.printStackTrace();
    }
  }
  public static void main(String[] args){
    new JImage();
  }
  class MyJPanel extends JPanel{
    @Override
    public void paintComponent(Graphics g){
      super.paintComponent(g);
      g.drawImage(bi, 0, 0, this);
    }
  } 
}