Screenshot |
A screenshot, screen dump, or screen capture is an image taken by the computer to record the visible items on the Computer display or another visual output device. Usually this is a digital image taken by the host operating system or software running on the computer device, but it can also mean when a capture is made by an external device such as a camera or something intercepting the video output of the computer.
Screenshots, screen dumps, or screen captures can be used to demonstrate a program, a particular problem a user might be having or generally when computer output needs to be shown to others or archived.
All three terms are often used interchangeably; however, some people distinguish between them as follows: ; Screenshot : Outputting the entire screen in a common format such as PNG or JPEG. ; Screen dump : The display system dumps what it is using internally upon request, such as XWD X Window Dump image data in the case of X11 or Portable Document Format in the case of Mac OS X. As of Mac OS X 10.4, pictures are no longer saved as PDF. They are saved as PNGs. ; Screen capture : Capturing the screen over an extended period of time to form a Video file.
=Taking screenshots =
There are numerous ways to take a screenshot on many operating systems, and applications. This article attempts to cover the ones that use standard software on each platform to achieve the task.
== Microsoft Windows ==
In Microsoft Windows a screenshot of the entire monitor, complete with taskbar, can be copied to the system clipboard by pressing the Print screen key. Alternatively, pressing Alt key + Print Screen will copy just the active window to the clipboard. You can then paste the clipboard into a program like MS Paint or Paint.NET to save it as an image file (for posting online, for instance), or paste it directly into a document.
=== Hardware overlays ===
Screenshots of games and media players sometimes fail, resulting in a blank rectangle. What s happening is the graphics are bypassing the normal screen and going to a high-speed graphics processor on your graphics card called the hardware overlay. Generally, there s no way to extract a computed image back out of the graphics card, though software may exist for special cases or specific video cards.
The trick to capturing those images is to turn off the hardware overlay. Because many computers have no hardware overlay, most programs are built to work without it, just a little slower.
There are two ways to turn off the overlay. The usual way is to turn it off in the settings for the specific game or media player. Instructions for Microsoft Media Player, Apple Quick Time, RealPlayer and WinAmp are [http://www.pixelmetrics.com/Tips/VidBlank/NonDvd.php here.]
You can also turn off the hardware overlay globally through Windows as shown [http://www.pixelmetrics.com/Tips/VidBlank/GlobalAcceleration.php here.] On Windows XP, go to Display Properties > Settings Tab > Advanced Button > Troubleshoot Tab. Set the Hardware Acceleration slider to one of the first three notches.
Store bought DVDs are a special case because they re encrypted using a patented algorithm called Content-scrambling system (CSS). Many, but not all, media players will only play DVDs on the overlay layer, where they can t be captured. For a review of which media players are best for screen capture, [http://www.pixelmetrics.com/Tips/VidBlank/DvdFrame.php go here.]
=== Scroll capture ===
Often a page or list doesn t show on your screen all at once, you must scroll to see it all. To capture those areas intact, use the scroll capture tool offered by some vendors. This tool captures the entire page or list, automatically scrolling vertically and/or horizontally as required.
=== Screen recording ===
The screen recording capability of some screen capture programs is a time-saving way to create instructions and presentations, but the resulting files are often large. For tips on managing the file size, with examples of the effects of each setting, [http://www.pixelmetrics.com/Tips/VidTips/ShrinkFile.php go here.] The professional way to create small, efficient demos is to build them from scratch in a Macromedia Flash editor, such as [http://www.swishzone.com/ SwiSH Max.], but this takes much more work.
Some sophisticated screen recording programs minimize file size by capturing only frames that change. In practice, you end up manually adding frames and doing other editing, so these programs fall mid-spectrum between simple recorders and building from scratch.
A common problem with video recordings is the action jumps, instead of flowing smoothly, due to low frame rate. Though getting faster all the time, ordinary PCs are not yet fast enough to play videos and simultaneously capture them at professional frame rates, i.e. 30 fps. For many uses, high frame rates are not required. For tips on maximizing frame rates, [http://www.pixelmetrics.com/Tips/VidTips/IncFps.php go here.] For those who must have professional frame rates, probably the easiest solution is to point a camcorder at the screen.
==Mac OS ==
To save an image of the entire screen to the startup disk in Mac OS press Command + Shift + 3.
To take a picture of part of the screen, press Command + Shift + 4 and then select the area to be captured.
To copy the capture to the clipboard instead, press the control key along with the other keys; it can then be pasted into another program to save in a raster graphics format.
To quickly select a window or menu, press the space bar after Command + Shift + 4, and click on the item to take a picture of (Mac OS X only).
Mac OS X v10.4 stores the captures on the desktop (~/Desktop/) in Portable Network Graphics format. Mac OS X v10.4 saves the capture in PNG, Mac OS X v10.3 and Mac OS X v10.2 saves them in Portable Document Format format, while Mac OS X v10.1 saved them as Tagged Image File Formats. As an alternative, the Grab program can be used to capture the screen, or the Preview application in Mac OS X v10.4. Both these methods support timed screen captures.
In Mac_OS#Mac_OS, the captures are saved as a ordered-numbered PICT files (Picture 1, Picure 2, Picture 3...) in the root level of the startup disk.
== X Window System ==
Since X Window System itself is not a desktop environment and only includes a very basic set of programs, methods of taking screenshots vary greatly on the platform. While xwd(1) is the closest standard way to do it in the X Window System, most people use other bundled utilities to achieve the task due to their ease of use.
=== xwd ===
On systems running the X Window System the standard utility to dump an image of an X Window is xwd(1), xwd produces an XWD image. It can be invoked in the following way: :xwd -root -out root.xwd xwd can also be used to dump a single window if provided with the -id option followed by the corresponding window id, for further info see man 1 xwd [http://www.hmug.org/man/1/xwd.html]. When run remotely, xwd is useful for taking screen shots of modal menus in action. The GIMP can be used to convert an XWD file to other more common formats such as Portable Network Graphics.
=== KDE and GNOME ===
In the K Desktop Environment, the built-in program KSnapshot is the default screen grabbing utility.
GNOME users can take a screenshot either by selecting Take Screenshot... from the Actions menu (in GNOME versions older than 2.10), by selecting Take Screenshot from the System... menu (GNOME 2.10 or greater) or by using one of the following two keyboard shortcuts:
== Screenshot software ==
There are many third-party programs available on different platforms to take screenshots with advanced functionality. Most computer graphics software (e.g., IrfanView, GIMP, and Photoshop) can acquire screenshots. Typically, these programs can be configured to include or exclude the mouse pointer, automatically crop out everything but the client area of the active window, take timed shots, and so on.
=== The GIMP ===
The GIMP can be used to take screenshots on any platform it is available on, simply navigate File->Acquire->Screenshot on the toolbox menu to capture either the current screen or choose timed mode.
=== ImageMagick ===
Alternatively if you have ImageMagick installed the following command can be used to import the root window and everything above to a PNG image file called root_window.png, it uses the convert(1) utility, you can take a screenshot of the entire contents of the screen with this command: :import -window root root_window.png Alternatively you can use the import command without any arguments, you will then be presented with a cursor with which you can click on a window and the image generated will contain a image of that window only. :import root_window.png
=Copyright issues=
Some companies believe the use of screenshots is an infringement of Copyright on their program. This is one of the issues solved by Trusted Computing. Under Trusted Computing, programs will be able to block the taking of screenshots of their windows. Countering this argument is the principle of fair use, which (in U.S. law) permits copying of images or text for criticism, comment, news reporting, teaching, scholarship, or research.
=See also=
*Thumbnail *Thumbshot *Screenshot map
=External links=
*[http://www.desktoprating.com Desktop Rating] - Submit screenshots and have them rated by others.
== Software ==
Third-party tools aren t required, but they make it the process faster and easier. The better tools also enable you to capture scrolling pages, the mouse pointer, audio and video.
*[http://www.techsmith.com/products/snagit/ SnagIt] - A screenshot utility for Windows. *[http://www.PixelMetrics.com CaptureWizPro] - Professional Windows utility for capturing screen images, scrolling areas, audio and video. *[http://www.inbit.com/fullshot.html FullShot] - Windows screen capture program; captures windows, documents and regions. *[http://www.screenshotmanager.de.vu ScreenshotManager] - Screenshot software for Windows. *[http://home.planet.nl/~harms646/software.html Simple Screenshot] - A simple and free screenshot program for Windows. *[http://sourceforge.net/projects/demostudio DemoStudio] - GPL program for recording software demonstrations, like Camtasia.|
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