Image applet

Hello!
I'm a student and my teacher, for a DSP course, asked us to write an applet to do morphological manipulation on images. I'm a totally newbie of Java but to gain a good mark I'm going to learn it :-)
So my first problem is to create an applet with two images (the original and the modified one) and some controls to change filter parameters. Original images (b/w or grayscale) should be selected by the user on his harddisk and maybe he could save the modified image (and filter parameters...).
My first goal is to create an applet which opens and show images of different sizes. These are the steps I did:
- Open NetBeans IDE 3.6
- Project Manager - New project (called "morph")
- File - New - Local directory
- File - New - Java GUI Forms - AWT Forms - Applet form with "morphapplet" name
Now I've a form editor like Delphi (the IDE I know best)...
After playing with the form properties (background color...) and changing the layout to absolute layout I added some objects (an "Hello World!" label and a button)
- Build - Compile
- Build - Execute
The applet shows... wow! :-)
Now in the applet folder I see an HTML page... wow I can run the applet... double click and the applet in my new FireFox 1.0 doesn't show... a red cross...
On java console I can read:
java.lang.NoClassDefFoundError: org/netbeans/lib/awtextra/AbsoluteLayout
     at morphapplet.initComponents(morphapplet.java:27)
     at morphapplet.init(morphapplet.java:15)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
java.lang.NoClassDefFoundError: org/netbeans/lib/awtextra/AbsoluteLayout
     at morphapplet.initComponents(morphapplet.java:27)
     at morphapplet.init(morphapplet.java:15)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
Where am I wrong?
Second question: where can I find "image" objects? In Delphi (for sure here it's different! note that I'm a newbie... :-)) I've an image object I can add to a form... in java how can I manage images?
Thanks!

I have posted a solution to this issue at:
http://teaching-2.cs.uml.edu/~heines/91.461/91.461-2004-05f/461-lecs/lecture29.jsp
Jesse
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jesse M. Heines, Ed.D.
Associate Professor
Dept. of Computer Science
University of Massachusetts Lowell
One University Avenue
Lowell, MA 01854-2881
E-Mail: mailto:[email protected]
Web: http://www.cs.uml.edu/~heines

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I've created a SSCE below but I can't seem to find the information I need to
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I found some mentions of links to the info, but when I followed them they were no longer there.
I would think the FAQ would have something about this but it doesn't appear to....
Can someone please point me to how to get the code formatted correctly?
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To use this code you will have to have an image called gdata.jpg in your "codebase" directory. What
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import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.net.*;
import javax.imageio.*;
import javax.swing.*;
import javax.swing.JApplet.*;
import javax.swing.event.*;
import java.io.*;
import java.io.Serializable;
import javax.swing.border.*;
public class testApplet extends JApplet implements SwingConstants,
ActionListener
JPanel testPanel = new JPanel();
JButton but = new JButton("test");
URL codeBase,graphURL;
Image gImage = null;
Icon iconImage=null;
// init -- Applet Init
public void init()
Container contentpane = getContentPane();
//Get Server IP information.
codeBase = getCodeBase();
try {
graphURL = new URL(codeBase+"gdata.jpg");
} catch(MalformedURLException e) { }
try {
ImageIO.setUseCache(false);
gImage = ImageIO.read(graphURL);
catch(IOException exc) { }
iconImage = new ImageIcon(gImage);
but.setIcon(iconImage);
testPanel.add(but);
but.addActionListener(this);
contentpane.add(testPanel);
// actionPerformed
public void actionPerformed(ActionEvent e)
if ( e.getSource() == but ) {
//If you uncomment out the 3 lines below, changing the name of the image,
// then it works, otherwise I always get the same image.
// try {
// graphURL = new URL(codeBase+"gdata1.jpg");
// } catch(MalformedURLException ex) { }
try {
ImageIO.setUseCache(false);
gImage = ImageIO.read(graphURL);
catch(IOException exc) { }
iconImage = new ImageIcon(gImage);
but.setIcon(iconImage);
but.revalidate();
testPanel.revalidate();
testPanel.repaint();
return;
Edited by: chippr on Sep 13, 2007 10:32 AM

chippr wrote:
That's odd. It looks like I'm using the same version jre plugin under windows...jre-6u2-windows-i586-p.exe.
Which gives me java 1.6_02
So you changed the image and then hit the button and it worked?Yep.
>
hmmmmm, I wonder what the difference is....I'm using firefox under windows, accessing a linux box
running apache....Same here, except I used appletviewer to test the code on the local machine. Let me upload it to my Linux box (running Apache) and I'll let you know what happens.

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I am able to reproduce this problem on the following PC configurations:
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Thank you in advance for your feedback.
Regards,
Marco.

Hi Marco,
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This behaviour that you are observing, weather the origin is something like I speculated or not, is not nice but I would not expect it to be fixed even if you filed a bug report. I guess we are left with relleasing all significatn memory structures in destroy. A simple way to code this is not to store anything in the member fields of the applet but in a separate class; then one has to do is to null that one reference from the applet to that class in the destroy method and everything will be relased when necessary. This way it is not easy to forget to release things.
Hey, here is a simple, imaginary, way in which the browser could cause this problem:
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Applet instantiateAndInit(Class appletClass) {
Applet applet=appletClass.newInstance();
applet.init();
return applet;
When the browser sees the applet tag it instantiates and inits the new applet as follows:
m_Applet=instantiateAndInit(appletClass);
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br Kusti

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OF

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You have not closed off the constructor function in class UFO. You need to add a '}' to close off the constructor.

Image Processing using applet

hi,
I am doing my project in java.My project is " Online Image Processing ".
I did some processing like gray Scale, Invert , Contrast and rotate 90 degree.
can any one help me for
1. I vant to rotate Image to 1 degree...
2. How to get Blure and Sharpen image?
3. Can i append frames inside applet?
plz Help me ..

I did not read the content of the links (To lazy) just found them for you.
You say that the examples use frames:
this should not be a problem as the required code is the same.
Tip:
How whould you display a image in a frame?
How whould you display a image in a applet?
Concentrate on the above 2 and simply change the code accordingly.
This should be easy also try asking google.

Image processing with applets

Hi
I need to create a website with several image processing applets on it. however although the applets work locally they will not load at all through a server (i'm a student) my supervisor tells me i cant use an applet to display an image stored on a server. but as applets specifically have getImage methods which must be able to get images from the server i think he is wrong but do not know how to do it.
Any advice will result in some really great Karma directed your way.
thanks

here's the code I use, make special note of the getDocumentBase(), as this request will be a URL based request, rather than a file read
try {
img = getImage(getDocumentBase(), "logo.gif");
}catch(Throwable t) {
System.out.println("Unable to load logo image",t);
t.printStackTrace();
hope this helps

Problem with Image I/O and applet

I am having trouble using Image I/O to load a PNG image in an applet. I am just using a very basic applet that simply loads the image from a URL and that's it, and the exception I get is -
java.lang.SecurityException: Unable to create temporary file
at java.io.File.checkAndCreate(File.java:1294)
at java.io.File.createTempFile(File.java:1385)
The simple applet is as follows -
import java.awt.image.*;
import java.net.*;
import java.io.*;
import javax.swing.*;
import javax.imageio.ImageIO;
public class CheckImageApplet extends JApplet
public BufferedImage bi = null;
public void init()
URL url = null;
BufferedImage bi = null;
try
url = new URL( "http://localhost/CheckImageSystem/checkimages/backGS.png" );
catch ( MalformedURLException mfue )
try
bi = ImageIO.read( url );
catch ( IOException ioe )
Any thoughts on this exception would be appreciated

It seems the line
bi = ImageIO.read( url );
fails. Can't see anything else. Perhaps this method needs to create a temp image for some reason, and tries to do this at the local harddrive (not allowed). Use getImage(URL, String); instead. ImageIO isn't intended for applets, I think, so you should use the applet methods.
Nille

Image applet

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