Wallpaper (computing)

Wallpaper (also desktop picture and desktop background) is 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 before Windows 7 (where it is called the Desktop "Background"), while Mac OS X calls it a "desktop picture" (previously, the term desktop pattern was used to refer to a small pattern that was repeated to fill the screen).

Formats

Images used as computer wallpaper are usually raster graphics with the same size as the display resolution (for example 1024×768 pixels, or 1280×1024 pixels) in order to fill the whole background.

Dimensions

Many screen resolutions are proportional in a 4:3 ratio, so an image scaled to fit in a different-sized screen will still be the correct shape, although that scaling may impact quality. Common wallpaper resolutions are connected to common desktop resolutions: 800x600, 1024x768, 1280x1024 and 1600x1200.

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 undue loss of quality.

Wallpapers are sometimes available in double-width versions (e.g. 2560×1024) 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. In these cases, the system's "default" background color is visible around the other two sides of the image.

Technical aspects

The main problem when enlarging an image to match the desktop resolution is the quality loss that appears during the resize process and the distorted image that appear when aspect ratio of the wallpaper is different than the aspect ratio of the desktop. However, there are applications that can automatically decide if an image is better to be displayed using its original resolution, resized (enlarge or shrink) or tiled. For example, BioniX Wallpaper Changer can automatically detect when the wallpaper image is smaller than the desktop or it has a different aspect ratio and apply a special image processing to make the discrepancy less visible. The process is backed up by a high-resolution resampling (using special resampling algorithms like B-Spline) in order to decrease the quality loss during image resizing. Even if the resulted wallpaper may not always match the desktop resolution and aspect ratio perfectly, the uncovered areas are generally reduced.

These problems can be eliminated by using vector images. However, these images are not very popular and are hard to find.

Image types

PNG and JPEG format are common. 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.

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. Early versions of Mac OS and Microsoft Windows allowed for small repeating patterns to tile the desktop.

History

Original computer wallpaper pattern, as used in Xerox's Officetalk and Star; actual size.

The first use of a distinguishable background in conjunction with overlapping windows was in an experimental office system, Officetalk, developed in 1975 at Xerox PARC on the Alto. Prior to that, the white backgrounds to overlapping windows (for example, in Smalltalk) could be difficult to distinguish from window interiors. The pattern used in Officetalk produced a 25% gray, using dots two pixels high to avoid flicker on the Alto's interlaced screen. The same pattern was adopted for the Xerox Star.

Apple used a similar gray background for their Lisa and Macintosh. However, since these machines had non-interlaced screens it was possible to use a less noticeable background pattern, formed from a simple 2x2 repeating pattern that gave a 50 percent gray. The introduction of color monitors for personal computers led to non-patterned, single-color backgrounds and then to arbitrary 'wallpapers'. There was a way to get a desktop picture on version's of the Mac OS before Mac OS 7.

Styles

File:IndianHeadTestCardComputerWallpaper0308.jpg

Retro-tech computer wallpaper: an Indian Head test card mosaic.

In Personal Use

Wallpapers used usually fall into one of the following categories: automobiles, models and celebrities, scenery, abstract art, movies, pets, family, symmetry, and personal photos.

In environments such as GNOME and Windows 7, wallpapers may be packaged along with desktop themes.

In Business Use

It is common to corporate logos or plain backgrounds on business computers, as such guidelines are often specified by the company.

It is common to create a wallpaper that displays a computer's name when using rack mounted computers through a KVM switch in order to easily identify to which computer the user is connected. Many companies will disable the display settings so the staff can't change the background, however this is often easy to get around for example: using the "set image as background" button in many web browsers.

List of X window managers that support desktop wallpaper

The following window managers provide support for desktop wallpaper:

• badwm
• icewm - provides wallpaper support via icewmbg
• kahaki
• pywm

Dynamic backgrounds

Some operating environments (e.g. KDE, Mac OS X, and Windows 7) allow a number of different wallpapers to be used, and changed from a set of selected images (either in order or shuffled) to display a different wallpaper at different times. In environments where this is not possible off-hand, third-party tools may be able to have this be done.

In Microsoft Windows

Microsoft Windows 98 through XP allowed webpages to be set as frames on the desktop which may be dynamic pages. Adobe Flash can also be used in these cases to create dynamic (and interactive) wallpapers as well by setting the wallpaper to an HTML file with an embedded Flash image. Microsoft Windows Vista Ultimate also has the ability to use a video as a wallpaper. Users can choose to use their own home videos which loop continuously, or use one already installed.

With Video Media

Some media players, like VLC, can redirect video playback to the desktop, allowing any video to be used as a wallpaper. Other such media players on Unix derivatives provide a similar option to output video to the background of X11.

Real-Time

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.

See also

• Category:Wikipedia featured desktop backgrounds
• Bliss
• Digital Blasphemy
• Caedes
• VRML wallpaper
• Wallpaper group

External links

• Wallpaper (computing) at Curlie

Make Desktop Wallpaper on Mac OS Snow Leopard