Output image file and displaying it on screen

[feda alshahwan]

I want to write a program that allow user to select a number and based on that number an image is displayed on the monitor so is there a way for displaying images

[Campbell Ritchie]

Of course there is. Go to the Java Tutorials and you find this, which should help.

We usually discuss this sort of thing in the Swing forum, so I shall move this thread.

[feda alshahwan]

I tried the following code from the tutorial but it didnot work

   
BufferedImage bi;
File f = new File("c:\images\myimage.png");
ImageIO.write(im, "png", f);
 

[Rob Spoor]

There are two ways of displaying an Image:

- paint it directly on a Graphics object, mostly in paintComponent:

class MyPanel extends JPanel
{
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.drawImage(...);
    }
}

- use a JLabel to display it. The most common way of getting an Icon that displays an Image is a class with a name that says it all: ImageIcon.

[feda alshahwan]

I tried it but it is not working?

[Rob Spoor]

What have you tried? Can you show us the image painting / creating code?

[Marky Vasconcellos]

Here a example:

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.*;

public class ImageScreen extends JPanel{
	private static final long serialVersionUID = 1L;
	private BufferedImage image;

	public ImageScreen() throws Exception {
		setMinimumSize(new Dimension(400,200));

		try {
                                                //Load the image
			image = ImageIO.read(new File("C:/image.png"));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paint(g);
		Graphics2D g2d = (Graphics2D) g.create();
                                //Paint it on screen
		g2d.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);
		g2d.dispose();
	}

	public static void main(String[] args) {
		JFrame window = new JFrame("An Image On Screen");
                                window.add(new ImageScreen());
                                window.setLocationRelativeTo(null);
                                window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                                window.pack();
                                window.setVisible(true);
	}

}

[feda alshahwan]

it is error in line 37 ImageScreen cannot be resolved to a type

[Campbell Ritchie]

No it isn't that error. You have an unnecessary declaration of a thrown Exception, which you ought to get rid of, and the invocation of super.paint(g); in the paintComponent() method should read "super.paintComponent(g);".

[feda alshahwan]

Hi, I got the following error
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
ImageScreen cannot be resolved to a type

at image.main(image.java:39)

My code is:

 
  import java.awt.Dimension;   
import java.awt.Graphics;   
import java.awt.Graphics2D;   
import java.awt.image.BufferedImage;   
import java.io.File;   
import java.io.IOException;   
  
import javax.imageio.ImageIO;   
import javax.swing.*;   
  
public class image extends JPanel{   
    private static final long serialVersionUID = 1L;   
    private BufferedImage images;   
  
    public void ImageScreen() throws Exception {   
        setMinimumSize(new Dimension(400,200));   
  
        try {   
                                                //Load the image   
            images = ImageIO.read(new File("C:/image1.png"));   
        } catch (IOException e) 
        {   
            e.printStackTrace();   
        }   
    }   
  
    @Override  
    public void paintComponent(Graphics g) {   
        super.paintComponent(g);   
        Graphics2D g2d = (Graphics2D) g.create();   
                                //Paint it on screen   
        g2d.drawImage(images, 0, 0, images.getWidth(), images.getHeight(), null);   
        g2d.dispose();   
    }   
  
    public static void main(String args[]) {   
        JFrame window = new JFrame("An Image On Screen");   
                                window.add(new ImageScreen());   
                                window.setLocationRelativeTo(null);   
                                window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   
                                window.pack();   
                                window.setVisible(true);   
    }   
  
}  

 

[Marky Vasconcellos]

Sorry.. i only copy&paste and change some things.
Its orginally a JWindow.
Here it's fixed.

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.*;

public class ImageScreen extends JPanel{
	private static final long serialVersionUID = 1L;
	private BufferedImage image;

	public ImageScreen() {
		setMinimumSize(new Dimension(400,200));

		try {
                                                //Load the image
			image = ImageIO.read(new File("C:/image.png"));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		Graphics2D g2d = (Graphics2D) g.create();
                                //Paint it on screen
		g2d.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);
		g2d.dispose();
	}

	public static void main(String[] args) {
		JFrame window = new JFrame("An Image On Screen");
                                window.add(new ImageScreen());
                                window.setLocationRelativeTo(null);
                                window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                                window.pack();
                                window.setVisible(true);
	}

}

[Rob Spoor]

Check your compiler error, and fix those first. Campbell already told you how to fix the main one.

Edit: never mind, you beat me to it

[Marky Vasconcellos]

Your code is wrong cause your class name is 'image' and have a Constructor named as ImageScreen and you call a new ImageScreen.

change

public class image extends JPanel

to:

public class ImageScreen extends JPanel

If you want more options in this Screen theres a JImagePanel who a friend mine posted in another forum.

i'm searching the code.. when i found i post.

[/code]

[Campbell Ritchie]

There is no end of confusion in this thread because people aren't copying each other's code correctly. Remember the tiniest spelling mistake can cause errors, and also look at this FAQ.

[feda alshahwan]

when running it it gives me this error " it doesnot contain a main type"

[Marky Vasconcellos]

How are you compiling and running?

[feda alshahwan]

using eclipse

[Campbell Ritchie]

Marky Vasconcellos wrote:How are you compiling and running?

I copied the code you had corrected, when I said to get rid of the Exception declaration, changed the name of the image file and compiled it. The code ran first time, showing the image, only the window started off very small.

[Marky Vasconcellos]

Campbell Ritchie wrote:

Marky Vasconcellos wrote:How are you compiling and running?

I copied the code you had corrected, when I said to get rid of the Exception declaration, changed the name of the image file and compiled it. The code ran first time, showing the image, only the window started off very small.

This is cause i hard-coded the size of the window.

But it's only a example.

@feda
Copy it on the Eclipse and change the Compilation Unit Name for the name of the class (ImageScreen).

[Campbell Ritchie]

What I meant was, your code worked first time, once I changed the name of the image file. I didn't mean the size was a particular problem. Sorry if I gave that impression. Au contraire, it was correct working code, which I shall remember for next time I can't get my own images displayed

[Marky Vasconcellos]

Dont worry. xD

[Jason Check]

If the image is not diplayed, I suggest you make the following changes of you paintComponent:

public void paintComponent(Graphics g) {
g.drawImage(image, 0, 0, this);
}

[Marky Vasconcellos]

Jason Check wrote:If the image is not diplayed, I suggest you make the following changes of you paintComponent:

public void paintComponent(Graphics g) {
g.drawImage(image, 0, 0, this);
}

If the Image is not displayed dont use a workaround.. try understand why its not being displayed.. using Grapgics drawimage directly can cause weird paintning in the screen.
I cant explain it very well.. but the code i post can work perfectly.

[Rob Spoor]

Jason Check wrote:If the image is not diplayed, I suggest you make the following changes of you paintComponent:

public void paintComponent(Graphics g) {
g.drawImage(image, 0, 0, this);
}

Also, you forgot to call super.paintComponent. And why did you make the method public? There is absolutely no need for that.

[Darryl Burke]

Rob Prime wrote:
Also, you forgot to call super.paintComponent.

Necessary if the image does not fill the component. If the image fills the visible area of the component, a call to the super method is redundant.

I usually keep it in and comment it out, if only to remind myself that it's not an oversight ;)

And why did you make the method public? There is absolutely no need for that.

Rob, would you have the time to explain why? I usually declare overridden protected methods as public, without ever really thinking about it.

the Sun tutorial on painting also declares the paintComponent overrids as public.
http://java.sun.com/docs/books/tutorial/uiswing/painting/step2.html
(about halfway down the page, in red)