I'd like to "capture" a screenshot of what a java applet would currently look like if it were loaded, effectively screenshoting an applet without the use of a vdu.
The purpose of this is to display the image to a user that doesn't have a JVM. Lets assume the applet is a digital clock and has no requirement on user input. So what could be done is set up a pc connected to a vdu, open the applet, schedule a script to take a screenshot and upload the image. Clients could then access what the applet would look like at any given time without the requirement on a jvm.
It'd be such a hassle to have a pc running all the time etc. Surely this could be done somehow without a display.
Would it be possible to create a virtual display in a jvm that can render an applet and then take a screen capture?
If this were possible then perhaps a really high resolution display could be virtualized to create a very high resolution screenshot.
The ScreenImage class should handle this.
Look at java.awt.Robot#createScreenCapture(java.awt.Rectangle)
If this would work, i would wonder, remind the sandbox, and as the above link stated "This will work whether you have an AWT or Swing application."
If you use a "rendering-engine" (composing each pixel to something paintable before repaint()'ing) within you applet, you could use this information and create an image.
Related
I am creating a program using Java Sockets in which I capture the client desktop and send messaging to client. Its working properly but now I want to block Client applications like Notepad, MS-Word, etc.
How can I do this?
Thanks.
It is hard to do using pure java API.
I do not know what do you mean when you say "block". The easiest way is to check from time to time running processes and kill one named "notepad" by executing taskkill from java.
If you wish to achieve effect of inactivity of application, i.e. user sees the notepad but cannot type you can do the following.
You have to check which application is on front. There is no clean pure java solution for this but you can probably write VBScript or JScript that does this task and run it from java. Once you detected that notepad is on top create transparent window (or even probably half-transparent window) that occupies full screen. Bring it on top. User will not be able to type into notepad because your window is on top but will see it.
Here is reference how to create transparent windows: http://java.sun.com/developer/technicalArticles/GUI/translucent_shaped_windows/
Good luck.
I'm trying to capture images by using webcam in an applet. The applet makes use of JMF. But I managed to run applet without actually installing JMF. I kept a button in HTML webpage so that when the button gets clicked, the applet should capture the image.
But for me it is giving a java.lang.RuntimeException: No permission to capture from applets. How can this exception be resolved so an applet can capture image using webcam in HTML page?
In order to capture images in an applet, it is necessary:
For you to digitally sign the code.
For the user to click "OK" when prompted to run the signed code.
If the functionality is being called from a button using JavaScript, wrap the Java code in one of the AccessController.doPrivileged(PrivilegedAction) variants.
AFAIR the installer for JMF does not have the 'allow capture from applets' checked by default. That needs to be reconfigured in the JMF options. I forget how.
Update
I dont want to give client package to extra overhead of the installation of JMF.
That is just silly.
The components of the JMF must be available on the run-time class-path of the applet, for it to function. If they are downloaded by the JRE using the applet element (or whatever), then the user has incurred that 'overhead'.
But perhaps you mean you don't want to make the end user run the installer that advises to 'reboot' at the end. In that case, you are missing my point while avoiding answering my question. That question, again, is "How did you get the DLL?".
Applets run with very limited permissions and that might be causing the issue.. Here is an old post which has information about signing an applet to get the necessary permissions..hope this helps
I think flash is a much better option. There are really easy solutions for that even using Javascript + Flash.
Take a look at this: http://www.xarg.org/project/jquery-webcam-plugin/
This question asked Too many times in this forum..
Anyways..Here is the solution: Java swing Program to capture webcam images
you have to modify it for applet which takes only 30 minutes
I wrote a Java application that uses the java.awt.Robot to take screen captures of the screen and was wondering if capturing a program using DirectX/OpenGL would be possible?
Each time I try to do this, I get a black screen
Don't know if this is really a solution but seems there's more possible ways to get the screenshot information using a "FrameGrabber" or some related class from JavaCV possibly: http://code.google.com/p/javacv/
Some of the final output shown on the screen could be calculated on a graphics card that has shaders set to act on the image data before it gets put into a display buffer for what's shown so it's possible some effects would be impossible to capture without an analog loopback (go from video out to video in on a capture card).
Related post How to take screenshots fast in Java?
OpenGL is a drawing API, not an all purpose interface to the graphics system. There were times, when taking screenshots with OpenGL was indeed possible through some dirty hacks. However recently I tried to re-implement this on modern OS to see if it still works, and no, it doesn't anymore.
Yes it is possible. But maybe only in limited circiumstances.
I've successfully captured the contents on OpenGL (jogl) windows on linux and windows using the Robot createScreenCapture.
Some specific information about the implementation that may be different for you:
The call to createScreenCapture was done from within the OpenGL
application.
The application used heavyweight GLCanvas
It used Java 6
Make sure you pass it the correct coordinates. You can get the screen coordinates to use from the GraphicsEnvironment
Uhh... a hard one ;o)
I had a try with some other screenshot utils and got a black screen, too. Looks like DirectX is passing the graphics directly to the monitor output. I am wondering if that could be accessed within a java application.
I want to automate an external application, but I have several problems:
How can I recognize a button or other field of an external application in Java?
I use the Robot class in Java for making notepad automation where I open notepad, select file menu, and save or exit, etc.
The problem is, it needs X,Y coordinates for the mouse pointer to go to the proper location.
I want to make it more dynamic, i.e. it should recognize the file menu of a running notepad anywhere on the desktop.
How can this be done in Java? Is there any class in Java I can use to do this?
Thanks everyone to give me response, I want to be more specific i want to know how can i make ui automation by using any tool if it is not possible in java or using any api of java.automation tool must be freeware.....i am searching net for that i found AutoIt is like that.But if any one do this type of things please share his/her experiance means is it possible to do that in AutoIt or not possible if not then which tool do that kind of things.
It is easy to integrate Sikuli into a Java-application since it is written in Java. Sikuli uses image recognition to find elements visible on the screen like buttons and such. It is very easy to use and provides an alternative for tasks that are difficult to handle with static positioning, like finding moving windows and such.
Take a look at this: http://sikuli.org/docx/faq/030-java-dev.html
Hope this helps!
You should have a look at Sikuli. It takes as inputs images of the ui elements to select an area in the targeted app. It's a UI Automation Application
That's a bit difficult to install (at least on Debian/Ubuntu, where I tested it), as you'll need a recent version of OpenCV, a particular version of JXGrabKey but the quality of the program worth the trip. Good Luck
Java doesn't have an API to examine the UI of another application; that would be a very big security risk.
Which is why the Robot class can only record events (key presses, mouse movements and clicks) but not which UI element was involved in most cases.
It would be possible to do more if the external application was written in Java because then, you could analyze the objects in memory but for obvious reasons, this isn't possible for C++ or .NET applications.
Is it possible to take a screen shot (using the Print Screen) and paste it from the System Clipboard directly into a web pages text area field (which I would create)? Do I need a browser plug-in? Can Flash do this?
**The solution only has to work in Internet Explorer.
This is not possible without a plugin.
It's not possible in Flash or Silverlight either, although it is possible in AIR.
I think you will have to write a custom ActiveX Control in order to do this. The control should automatically take a screenshot and send captured image to server-side code..
There is one more option - create a java applet, which will do the job, and also will help you to avoid cross browser issue.