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Screenshot
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A screenshot, screen capture, or screen dump is an image taken by the computer to record the visible items displayed on the monitor 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 be a capture made by a camera or a device 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, or to simply show off what you do on your computer to others.
All three terms are often used interchangeably; however, some people distinguish between them as follows:
Screenshot: Outputting the entire screen in a common bitmap image format such as BMP, 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 PNG in the case of Mac OS X.
Screen capture (screencaps) : Capturing the screen over an extended period of time to form a video file.
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Encyclopedia
A screenshot, screen capture, or screen dump is an image taken by the computer to record the visible items displayed on the monitor 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 be a capture made by a camera or a device 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, or to simply show off what you do on your computer to others.
All three terms are often used interchangeably; however, some people distinguish between them as follows:
Screenshot: Outputting the entire screen in a common bitmap image format such as BMP, 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 PNG in the case of Mac OS X.
Screen capture (screencaps) : Capturing the screen over an extended period of time to form a video file. (see video capture)
Game screenshots
Screenshots are used on packaging video games. Throughout the history of screenshots, there have been some deceptive practices, such as using a screenshot from a computer platform with better graphics. Due to complaints by consumers, software companies began putting captions below games such as "Screenshot from Amiga version" or "Actual C64 screenshot".
In the 1990s, when pre-rendered or filmed videos became a part of intermissions in games, some game boxes included screenshots from the in-game videos, which deceived potential buyers about overall game play.
There are many websites serving as online repository for videogames and mmorpg screenshots. The main are , Koinup, AvatarsUnited. Some of them are both screenshots repository and web portal for gamers and mmorpg players
Internet uses
It has become popular in the internet fandom culture to use screencaps of movies and television shows in the creation of fanart, most commonly as icons for LiveJournal, MSN Messenger, and Internet forums about those topics. Websites and various communities have been created to distribute these screencaps.
Built-in screenshot functionality
Microsoft Windows
On Microsoft Windows, pressing the Print Screen key captures a screenshot of the entire desktop area, and places it in the clipboard. Pressing the combination of Alt-Print Screen captures only the current active window. However, by first pressing Alt, then the hotkey of the dropdown menu you wish to illustrate, you can capture dropdown menu contents. In most versions of Windows, screenshots captured this way do not include the mouse pointer.
Video content in programs using a hardware overlay video renderer is not captured by the method described above. Windows Media Player on Windows XP in its default configuration on supported hardware is affected by this. However, some third-party applications can capture overlay images.
By default, Windows does not save the screenshot to an image file; the user is required to paste the image into a separate imaging program (such as Microsoft Paint which is built-in) for saving. Some programs, however, particularly multiplayer online games, will automatically save screenshots in a specified folder. As of Windows XP, it is no longer possible to take screenshots of full-screen DOS windows without other software.
Windows Vista includes a utility called Snipping Tool, first introduced in Windows XP Tablet PC Edition. It is a screen-capture tool, that allows for taking screenshots (called snips) of windows, rectangular areas, or a free-form area. Snips can then be annotated, saved as an image file or as an HTML page, or emailed.
Unfortunately, it does not work with non-tablet XP versions but www.bhelpuri.net/Snippy/ represents an XP compatible equivalent.
For programmatic access, application developers can use GDI, DirectX or the Windows Media Encoder API to capture the screen.
Mac OS X
On Mac OS X, pressing Command-Shift-3 takes a screenshot of the entire screen, and Command-Shift-4 takes a screenshot of a chosen area of the screen or if you press Space afterwards you can choose a window on the screen to individually screenshot. These images are saved to the desktop, but if you hold down the control key with the rest of the keyboard shortcut, the pictures are copied to the clipboard instead. These shortcuts also work in Mac OS Classic.
You can also use the Grab application to take screenshots.
A shell utility called "screencapture" (located in /usr/sbin/screencapture) can be used from the Terminal application or in shell scripts to capture screenshots and save them to files. Various options are available to choose the file format of the screenshot, how the screenshot is captured, if sounds are played, etc. The manual page (available via the command "man screencapture") explains all the options. This utility might only be available when the Mac OS X developer tools are installed.
iPhone
A screen shot can be taken with the iPhone and iPod Touch by pressing and holding the Home button, then pressing the Sleep/Wake button. You can also press and hold the Sleep/Wake button first, before pressing the Home button. The screen will flash and the picture will be stored in the camera roll. From there you can sync it to your computer. You can take a screen shot within any application. The screen shot feature is only available with the 2.0 software update.
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.
Video screen captures
Most of the major operating systems have no built-in mechanisms to record videos of the screen (recording how the user moves his mouse around, clicks icons, types text etc. as a movie).
Unix-like systems like the Debian’s ones include programs like recordmydesktop and its wrappers (records into Theora), istanbul (also supports Theora), and byzanz (GIF).
Third party screenshot software
There are many third-party programs available on different platforms to take screenshots with advanced functionality. Some computer graphics software 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, areas of the screen not visible on the monitor (autoscroll), capture the content of overlays and so on.
Examples include:
Video screen captures
For the systems which do not include video capturing software by default, the software listed in the section above as default for some Unix-like systems, and a multitude of other utilities have come up to fill this void, such as SnapZ Pro X on Mac OS X, and Windows Media Encoder on Windows XP.
Common technical issues
Hardware overlays
On Windows systems, screenshots of games and media players sometimes fail, resulting in a blank rectangle. The reason for this is that the graphics are bypassing the normal screen and going to a high-speed graphics processor on the graphics card by using a method called hardware overlay. Generally, there is no way to extract a computed image back out of the graphics card, though software may exist for special cases or specific video cards.
One way these images can be captured 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. In Windows XP, this is disabled by opening the Display Properties menu, clicking on the "Settings" tab, clicking, "Advanced", "Troubleshoot", and moving the Hardware Acceleration Slider to "None."
Free software media players may also use the overlay, but often have a setting to avoid that, or dedicated screenshot functions.
Mac OS X DVD player deactivates the built-in screenshot feature, but it is still possible to capture the image or the video with third party software, or by using the "screencapture" command in the terminal.
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.
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 frame/s. For many cases, high frame rates are not required. This is not generally an issue if simply capturing desktop video, which requires far less processing power than video playback, and it is very possible to capture at 30 frame/s. This of course varies depending on desktop resolution, processing requirements needed for the application that is being captured, and many other factors.
Copyright issues
Some companies believe the use of screenshots is an infringement of copyright on their program, as it is a derivative work of the widgets and other art created for the software. Regardless of copyright, screenshots may still be legally used under the principle of fair use in the U.S. or fair dealing and similar laws in other countries.
Preventing copying is one of the issues that Trusted Computing seeks to address. Under Trusted Computing, the user would be prevented from taking screenshots when certain programs are running, regardless of the wishes of the computer's owner.
See also
External links
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