Solved

Java robot class capturing black/blank desktop images - Help

Posted on 2007-03-25
9
1,632 Views
Last Modified: 2013-12-29
I am currently capturing various images from the desktop using the robot class. Yet every now and again my program will take a completely black image, which renders my program useless. Does anyone have any suggestion why this is happening ? and what I can do prevent or fix it ?

At the moment I just restart my computer and it seems fine, but I don't want this to happen on my clients computer.

Thanks
0
Comment
Question by:mr_mooray
9 Comments
 
LVL 86

Expert Comment

by:CEHJ
ID: 18787711
How are you running the Robot?
0
 

Author Comment

by:mr_mooray
ID: 18787773
     try {
                  Robot robot = new Robot();

                  //capture a screenshot of desktop size
                  Rectangle captureSize = new Rectangle(Toolkit.getDefaultToolkit()
                              .getScreenSize());
                  BufferedImage capture = robot.createScreenCapture(captureSize);

                  //save to file
                  ImageIO.write(capture, "bmp", new File("C:/Desktop.bmp"));

                  //Set Desktop Image
                  desktopImage = capture;

            } catch (HeadlessException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
            } catch (AWTException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
            } catch (IOException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
            }
0
 
LVL 35

Expert Comment

by:TimYates
ID: 18787868
The screensaver hasn't kicked in has it?
0
Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 

Author Comment

by:mr_mooray
ID: 18787881
No all screen savers are disabled, it just returns a completely black image. I don't think its my code, do you think it could be a different program interfering ?
0
 
LVL 30

Accepted Solution

by:
Mayank S earned 250 total points
ID: 18788981
http://forum.java.sun.com/thread.jspa?threadID=465261&messageID=2142224 says createScreenCapture () is slow - try JNI.
0
 
LVL 3

Assisted Solution

by:stimpyjcat
stimpyjcat earned 250 total points
ID: 19397447

There are some instances where the robot (at least in its current implementation) is not capable of capturing the screen contents.   Some transparent windows, video, or other direct-to-hardware rendering may not be available for capture by the robot.  The capture will also be blank on w32 systems when effectively run as a service as the System user without desktop access.

If the capture is intermittently getting invalid results, then there's likely a bug in the capture.  One workaround would be to sample a few pixels to ensure the capture is not blank, re-capturing if the capture appears to have failed.

0
 
LVL 35

Expert Comment

by:girionis
ID: 19675493
mr_mooray,
This question has been classified as abandoned.  I will make a recommendation to the moderators on its resolution in approximately four days.  I would appreciate any comments by the experts that would help me in making a recommendation.

It is assumed that any participant not responding to this request is no longer interested in its final disposition.

If the asker does not know how to close the question, the options are here:
http://www.experts-exchange.com/help.jsp#hs5

girionis
EE Cleanup Volunteer
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
by zero exception 10 52
Java program running SQL query 5 37
running on tomcat not jboss eap 7.0 3 18
American Express @Work site and Java 4 20
Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
This video teaches viewers about errors in exception handling.
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.

839 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question