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| The terms wallpaper and
desktop picture refer to an image used as a background on a computer screen, usually for
the desktop of a graphical user interface. 'Wallpaper' is the term used in Microsoft
Windows, while the Mac OS calls it a 'desktop picture' (prior to Mac OS X, the term
desktop pattern was used to refer to a small pattern that was repeated to fill the
screen). Images used as computer wallpaper are usually raster graphics with the same size as the display resolution (for example 1024Г—768 pixels, or 1280Г—1024 pixels) in order to fill the whole background. Many screen resolutions are proportional, so an image scaled to fit in a different-sized screen will often be the correct shape, albeit that scaling may impact quality. PNG and JPEG format are common. Users with widescreen (16:9 or 16:10) monitors have different aspect ratio requirements for wallpaper, although images designed for standard (4:3) monitors can often be scaled or cropped to the correct shape without loss of quality. Wallpapers are sometimes available in double-width versions (e.g. 2560Г—1024) for displaying on multi-monitor computers, where the image appears to fill two monitors. Some display systems allow unconventionally-proportioned images (1:1, 2:1, or even 1:3) to be scaled without change of proportion, to fit the screen, whether it be 16:9 or 4:3. The image would be sized just large enough that one pair of edges touch the edges of the screen, but not all four, as this would unduly distort the image. Most display systems are capable of specifying a single-colour to use as the background in place of a wallpaper, and some (such as KDE or GNOME) allow colour-gradients to be specified. Microsoft Windows 3.x and 9x systems allow using editable repeating two-color 8Г—8 tiles for background. Some desktop systems, such as Mac OS (version 8.6 or later), KDE (version 3.4 or later), and GNOME, support vector wallpapers (PICT in Mac and SVG in KDE and GNOME). This has the advantage that a single file may be used for screens of any size, or stretched across several screens, without loss of quality. Some operating environments (e.g. KDE and Mac OS X) allow a number of different wallpapers to be used, and "rotated" to display a different wallpaper at different times, to display a random image from a directory. If the facility is not available in the OS' wallpaper settings, it may be possible to get an external program which can change the wallpaper at certain times. Microsoft Windows 98 and higher allow webpages to be set as frames on the desktop which may be dynamic pages. Programs such as Xplanet and EarthDesk use Internet connections and graphics calculations to change the wallpaper with real data, such as a shadowed view of the earth, the latest cloud or weather map, or various events. Some media players can redirect video playback to desktop, allowing any video to be used as a wallpaper. Other tools (for example WireChanger) can add interactive widgets to a wallpaper, such as calendar, notes, RSS feed, or generate a wallpaper image using various algorithms. Macromedia/Adobe Flash animated movies and games can be set a dynamic interactive background as well. Point your desktop background settings to an html file with embedded flash movie instead of an image. Computer wallpaper is a close friend of computer screensaver. A screensaver is a computer program originally designed to conserve the image quality of computer displays by blanking the screen, or filling it with moving images or patterns when the computer was not in use. Today, screensavers are primarily used for entertainment or security purposes. Before the proliferation of LCD screens, most computer screens depended on cathode ray tubes (CRTs). Images on a CRT monitor are generated using electron beams which are emitted from electron guns at the back of the tube, and manipulated by electromagnetic fields to form images line-by-line on the phosphorescent screen many times per second. In some situations the images displayed on the screen constantly change, but in other cases some areas of the screen, or the screen as a whole, change very little (the taskbar in Microsoft Windows, for example). When the same image is displayed on a CRT screen for long periods of time, the properties of the exposed areas of phosphor coating on the inside of the screen gradually and permanently change, eventually leading to a darkened shadow or "ghost" image on the screen. Televisions, oscilloscopes and other devices that use CRTs are all susceptible to phosphor burn-in, as are plasma displays to some extent. Mac OS X Screen Saver Screensaver programs were originally designed to help avoid these effects by automatically changing the images on the screen when the computer was not in use (thus "saving" the screen). They can be usually set up to launch automatically, waiting a specified amount of time after the last keystroke or the last mouse movement made by a user. The screensaver then blanks the screen, or more commonly produces animation effects, thus avoiding any "fixed" images. The screensaver remains active until a user presses a key or makes a mouse movement. At that moment, the screensaver closes and the former screen contents are restored, allowing the user to work again. For CRTs used in public embedded applications such as ATMs and railway ticketing machines, the risk of burn-in is especially high because a stand-by display is shown whenever the machine is not in use. Older machines designed without burn-in problems taken into consideration often display evidence of screen damage, with images or text such as "Please insert your card" (in the case of ATMs) visible even when the display changes while the machine is in use. Blanking the screen is out of the question as the machine would appear to be out of service. In these applications, burn-in is prevented by shifting the position of the display contents every few seconds, or by having a number of different images that are changed regularly. Modern CRTs are much less susceptible to burn-in than older models due to improvements in phosphor coatings, and because modern computer images are generally lower contrast than the stark green- or white-on-black text and graphics of earlier machines. LCD computer monitors, including the display panels used in laptop computers, are not susceptible to burn-in because the image is not directly produced by phosphors (although they can suffer from a less extreme and usually non-permanent form of image persistence). For these reasons, screensavers today are primarily decorative or for entertainment, and usually feature moving images or patterns and sometimes sound effects. Einstein@Home automatically scans astronomical data for evidence of pulsars One increasingly popular application is for screensavers to activate a useful background task, such as a virus scan or a distributed computing application (such as the SETI@home project). This is convenient because these applications only use resources when the computer would be otherwise idle. We hope You will enjoy our free wallpapers and photos. Feel free to use any image you will find on Beach9.com |
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