Welcome to the Java Programming Forums


The professional, friendly Java community. 21,500 members and growing!


The Java Programming Forums are a community of Java programmers from all around the World. Our members have a wide range of skills and they all have one thing in common: A passion to learn and code Java. We invite beginner Java programmers right through to Java professionals to post here and share your knowledge. Become a part of the community, help others, expand your knowledge of Java and enjoy talking with like minded people. Registration is quick and best of all free. We look forward to meeting you.


>> REGISTER NOW TO START POSTING


Members have full access to the forums. Advertisements are removed for registered users.

Results 1 to 4 of 4

Thread: Java tip Sep 22, 2010 - "Screenshots" of swing components

  1. #1
    Super Moderator helloworld922's Avatar
    Join Date
    Jun 2009
    Posts
    2,896
    Thanks
    23
    Thanked 619 Times in 561 Posts
    Blog Entries
    18

    Default Java tip Sep 22, 2010 - "Screenshots" of swing components

    Introduction

    Ever want to take a screenshot of only your program's GUI? In this tip, I will discuss a simple mechanism to allow you to do just that. In fact, you can even take screenshots of only portions of your program's GUI.

    Difficulty: Easy-medium. Knowledge of Java syntax is assumed, but the code is fairly easy to read and follow.

    Awt and Swing Paint method

    This tip is a very simple way to take a "screenshot" of a Java Awt/Swing component. It plays on the fact that the paint method can take any Graphics object regardless of what it's actually painting to. Also, because the paint method recursively paints sub-components, you will get all of those components as well. If you only want your component, then call the paintComponent method with the image's Graphics object.

    There is one thing to keep in mind before using this (there might be others, but this is the only one I could think of off the top of my head):

    1. Your paint method should not modify the state of your program. This should already be the case, and if it's not, you may want to reconsider how your program is designed.

    Code

    Here's the code, it's fairly simple. Just create an image that's the same size as the component you want to take a screenshot of, and call the paint method on the image's graphics object.

            // component is the component we want to take a screen shot of
            BufferedImage img = new BufferedImage(component.getWidth(), component.getHeight(), BufferedImage.TYPE_4BYTE_ABGR);
            Graphics gx = img.getGraphics();
            component.paint(gx);

    Conclusion

    Where would you want to use this?

    One application I had was in a Plotting application (maybe this will be my next tip, it's still not quite done yet). It looks great on-screen, but It would be much better if I could save the contents into an Image. Yes you could use the PrntSc button and take a screen-shot from your OS, but I find this method has several advantage:

    1. No Photoshopping is required to get your image down to the correct size
    2. You can layer other windows/components on top of the component you want to take a screen-shot of and you will still get only your component.
    3. You can "zoom" in or out by passing in a graphics object that is larger or smaller than the actual component you are interested in. Do note that if you try this, your painting methods should not use the component's getWidth() or getHeight() methods. Instead, get the graphics object's clipping bounds if you want your component to be .be able to be resized. I believe most of the default AWT/Swing components already use the graphics's clip bounds instead of the component's width/height so you should be ok here.

    Here's a sample screen-shot I made:

    test.jpg

    That's all there is for this tip. Happy coding

  2. The Following User Says Thank You to helloworld922 For This Useful Post:

    JavaPF (September 22nd, 2010)


  3. #2
    mmm.. coffee JavaPF's Avatar
    Join Date
    May 2008
    Location
    United Kingdom
    Posts
    3,336
    My Mood
    Mellow
    Thanks
    258
    Thanked 287 Times in 225 Posts
    Blog Entries
    4

    Default Re: Java tip Sep 22, 2010 - "Screenshots" of swing components

    Very interesting read once again!! Loving this feature
    Please use [highlight=Java] code [/highlight] tags when posting your code.
    Forum Tip: Add to peoples reputation by clicking the button on their useful posts.

    Looking for a Java job? Visit - Java Programming Careers

  4. #3
    Member
    Join Date
    Jul 2010
    Location
    Washington, USA
    Posts
    307
    Thanks
    16
    Thanked 43 Times in 39 Posts

    Default Re: Java tip Sep 22, 2010 - "Screenshots" of swing components

    Hey, I did something just like this for adding a report/screenshot function in my game.

  5. #4
    Forum VIP
    Join Date
    Jun 2011
    Posts
    278
    My Mood
    Stressed
    Thanks
    41
    Thanked 77 Times in 65 Posts
    Blog Entries
    4

    Default Re: Java tip Sep 22, 2010 - "Screenshots" of swing components

    I used something very similar to this (but with TYPE_INT_ARGB) and then used the javax.imageio package to save it as a PNG. Works like a charm.

     public void saveToFile(String filename) {
            try {
                // Save as PNG
                String fn = filename + ".png";
                File file = new File(fn);
                ImageIO.write(image, "png", file);
            } catch (IOException e) {}
        }

  6. The Following User Says Thank You to ChristopherLowe For This Useful Post:

    JavaPF (June 10th, 2011)

Similar Threads

  1. Java says:"Hello World". I say:"It works!"
    By Davidovic in forum Member Introductions
    Replies: 4
    Last Post: June 29th, 2010, 07:13 AM
  2. "showMessageDialog" method in swing package
    By Delmi in forum Java Theory & Questions
    Replies: 1
    Last Post: May 13th, 2010, 02:52 PM
  3. "java.lang.NoSuchMethodError: main" and "fatal exception occured."
    By joachim89 in forum What's Wrong With My Code?
    Replies: 2
    Last Post: January 10th, 2010, 07:35 AM
  4. Replies: 1
    Last Post: October 25th, 2009, 11:54 AM
  5. [SOLVED] "GridLayout" problem in Java program
    By antitru5t in forum AWT / Java Swing
    Replies: 3
    Last Post: April 16th, 2009, 10:26 AM