java applet screenshot

[antoine c.]

dear experts,

i am wondering if this simple screenshot.java program, developed by
Marco Schmidt could be ported as a applet?

I would like to port such a program as an applet i.e. take a
screenshot of the web user's browser's front window, get the picture
transferred and written on the server side and email the resulting
image back to the web user. My aim is also that all the whole process
remains painless for the user.

My question: do you know if such an implementation the current program
is possible? Is it possible to send the BufferedImage image =
robot.createScreenCapture() and write it on the server side? Would any
restrictions occur, or certificate need to be established?

You would save me all a lot of time if you could answer the question.

for a complete link to the following code, please take a look at:
http://www.geocities.com/marcoschmidt.geo/java-save-screenshot.html


/*
* Screenshot.java (requires Java 1.4+)
*/

import java.awt.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;

public class Screenshot {
public static void main(String[] args) throws Exception {
// make sure we have exactly two arguments,
// a waiting period and a file name
if (args.length != 2) {
System.err.println("Usage: java Screenshot " +
"WAITSECONDS OUTFILE.png");
System.exit(1);
}
// check if file name is valid
String outFileName = args[1];
if (!outFileName.toLowerCase().endsWith(".png")) {
System.err.println("Error: output file name
must " +
"end with \".png\".");
System.exit(1);
}
// wait for a user-specified time
try {
long time = Long.parseLong(args[0]) * 1000L;
System.out.println("Waiting " + (time / 1000L)
+
" second(s)...");
Thread.sleep(time);
} catch(NumberFormatException nfe) {
System.err.println(args[0] + " does not seem
to be a " +
"valid number of seconds.");
System.exit(1);
}
// determine current screen size
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
Rectangle screenRect = new Rectangle(screenSize);
// create screen shot
Robot robot = new Robot();
BufferedImage image =
robot.createScreenCapture(screenRect);
// save captured image to PNG file
ImageIO.write(image, "png", new File(outFileName));
// give feedback
System.out.println("Saved screen shot (" +
image.getWidth() +
" x " + image.getHeight() + " pixels) to file
\"" +
outFileName + "\".");
// use System.exit if the program hangs after writing
the file;
// that's an old bug which got fixed only recently
// System.exit(0);
}
}


thank you,

antoine

 

[Matt Humphrey]

dear experts,

i am wondering if this simple screenshot.java program, developed by
Marco Schmidt could be ported as a applet?

I would like to port such a program as an applet i.e. take a
screenshot of the web user's browser's front window, get the picture
transferred and written on the server side and email the resulting
image back to the web user. My aim is also that all the whole process
remains painless for the user.

My question: do you know if such an implementation the current program
is possible? Is it possible to send the BufferedImage image =
robot.createScreenCapture() and write it on the server side? Would any
restrictions occur, or certificate need to be established?

I would think at the very least it would be (or should be) some kind of
security violation for an untrusted applet to get a full screen shot. I
think "CanvasAccess" or possibly "UniversalTopLevelWindow" privileges would
be required. If you can get the user to agree to that privilege, however
(by requesting it with a signed applet), everything else should work
(presuming you're sending the image back to the original server. Saving it
as a file is another privilege.)

Cheers,
Matt Humphrey (e-mail address removed) http://www.iviz.com/

 

[Andrew Thompson]

i am wondering if this simple screenshot.java program, developed by
Marco Schmidt could be ported as a applet?

Applets operate within a tighter security
sandbox than applications, but once the
security restrictions are relaxed, thet
can achieve anything an application can..

I would like to port such a program as an applet i.e. take a
screenshot

And that is definitely an activity that will
require the code to be jar'd and signed. Then,
if the user agrees to accept the code, it can proceed.

..of the web user's browser's front window, get the picture
transferred and written on the server side

Would require JSP/Servlets or some other
server side support..

..and email the resulting
image back to the web user.

What is the point of the round trip to the server?
Does this entire process have an advantage over
a short page describing this* key and it's effects..
<http://www.physci.org/kbd.jsp?key=prt>

And, ..why exactly does the user want a
screenshot of your web-page?

My aim is also that all the whole process
remains painless for the user.

Accepting a signed applet and fessing up an
email address to the author seems more painful
than doing a 'print screen' somehow..

My question: do you know if such an implementation the current program
is possible?

Possible, yes, though I still do not quite
get the point of what you are trying to achieve.

[ F'Ups set to c.l.j.gui. 'cos my newsreader
whines at me if I do not set F'Ups.. ]