Drawing an image on JPanel

[mneskovic]

Hello!

I have made applet using Swing, which has one JPanel and one DesktopPane with labels and sliders. I want to draw shapes and images on JPanel, but I don't know how to do it. I tried to draw image, but I lose all my panels and got just picture. I think that main problem is that I don't know how to access to my JPanel on which I want to draw and then to make drawing.

I have just made a new panel and wrote code for connectiong with the applet. I also wrote code for drawing an image, but it doesn't work. Can anybody help?
Here is the code:

package org.me.pack;

import javax.swing.JPanel;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import java.net.*;

public class MajaPanel extends JPanel {
    private static BasicStroke bs1 = new BasicStroke(3.0f);
    BufferedImage bmp;
    BufferedImage bimg;

 public void init() {
      URL slika;
        try {
            slika = new URL("http://www.wolflodge.org/prophecy/endofdays_2/White_Rabbit.gif");
            try {
                bmp = ImageIO.read(slika);
            } catch (IOException ex) {
                Logger.getLogger(Simulacija.class.getName()).log(Level.SEVERE, null, ex);
            }
        } catch (MalformedURLException ex) {
            Logger.getLogger(Simulacija.class.getName()).log(Level.SEVERE, null, ex);
        }
 }

public void render(int w, int h, Graphics2D g2) {
        g2.drawImage(bmp, null, this);
        }
        public Graphics2D createGraphics2D(int w, int h) {
        Graphics2D g2 = null;
        if (bimg == null || bimg.getWidth() != w || bimg.getHeight() != h) {
            bimg = (BufferedImage) createImage(w, h);
        }
        g2 = bimg.createGraphics();
        g2.setStroke(bs1);
         g2.setBackground(getBackground());
        g2.clearRect(0, 0, w, h);
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        return g2;
}

public void paint(Graphics g) {

	Dimension d1 = getSize();
        Graphics2D g2=(Graphics2D)g;
        render(d1.width, d1.height, g2);
        g.drawImage(bimg, 0, 0, this);
        g2.dispose();
    }
}

[PhHein]

Read this: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

[bleah]

I guess you should override paintComponent( Graphics g ) method and call super.paintComponent( g ); before calling anything else so you won't lose your panels.

[mneskovic]

Problem solved! Thank you, guys for interesting :) I have new problem: I drow gif images and rectangle and I would like to make them not transparent, because rectangle edges go over them, but I don't know how to fix this. I read something about opaque, but where to set it?

Here is the code:

package org.me.pack;
import java.awt.Color;
import javax.swing.*;
import javax.imageio.ImageIO;
import java.net.URL;
import java.awt.Image;
import java.awt.Graphics;
public class MajaPanel extends JPanel
{
  public Image backgroundImage;
  public MajaPanel()
  {
                setOpaque(true);
      try
      {
         this.backgroundImage = ImageIO.read(new URL("http://www.ajmalbeig.addr.com/pgc/images/icons/icon_computer.GIF"));
      }
      catch(Exception e)
      {
         throw new RuntimeException(e);
      }
  }
  public static void main(String[] args)
  {
     JFrame frame = new JFrame("Testiranje panela");
     frame.setContentPane(new MajaPanel());
     frame.getContentPane().setLayout(null);
     frame.setSize(565,214);
     frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
     frame.setVisible(true);
  }
  protected void paintComponent(Graphics g)
  {
     
     g.drawImage(backgroundImage,30,70,null);
     g.drawImage(backgroundImage,580,70,null);
     g.setColor(Color.blue);
     g.fillRect(90, 100, 500, 14);
     g.fillRect(50, 50, 10, 10);
  }
}