In computing

Computing

Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...

, a skin is a custom graphical appearance achieved by the use of a graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 (GUI) that can be applied to specific software

Computer software

Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....

 and website

Website

A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

s to suit the purpose, topic, or tastes of different users.
A skin may be associated with themes.

Software that is capable of having a skin applied is referred to as being skinnable, and the process of writing or applying such a skin is known as skinning. Applying a skin changes a piece of software's look and feel

Look and feel

In software design, look and feel is a term used in respect of a graphical user interface and comprises aspects of its design, including elements such as colors, shapes, layout, and typefaces , as well as the behavior of dynamic elements such as buttons, boxes, and menus...

 — some skins merely make the program more aesthetically pleasing, but others can rearrange elements of the interface, potentially making the program easier to use. Although often used simply as a synonym for skin, the term theme normally refers to less-complex customizations, such as a set of icon

Icon (computing)

A computer icon is a pictogram displayed on a computer screen and used to navigate a computer system or mobile device. The icon itself is a small picture or symbol serving as a quick, intuitive representation of a software tool, function or a data file accessible on the system. It functions as an...

s and matching colour scheme for an operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 — notably, this is how the term was used in association with Windows 95

Windows 95

Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...

 and Microsoft Plus!

Microsoft Plus!

Microsoft Plus! was a commercial operating system enhancement product by Microsoft. The last edition is the Plus! SuperPack, which includes an assortment of screensavers, themes, and games, as well as multimedia applications...

 for Windows 95.

Common skinnable applications

Probably the most popular skins are for instant messaging

Instant messaging

Instant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet...

 client

Client (computing)

A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....

s, media center

Home theater PC

A Home Theater PC or Media Center appliance is a convergence device that combines some or all the capabilities of a personal computer with a software application that supports video, photo, music playback, and sometimes video recording functionality...

, and media player software, such as Trillian and Winamp

Winamp

Winamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features.Winamp...

, due to the association with fun that such programs try to encourage. In programs that use a cross-platform

Cross-platform

In computing, cross-platform, or multi-platform, is an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computer platforms...

 GUI toolkit, rather than using the standard interface for the operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 on which they are running, it is relatively easy to add functionality to alter this interface from within the program. For instance, Google Chrome

Google Chrome

Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...

, Mozilla Firefox

Mozilla Firefox

Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...

 and Opera

Opera (web browser)

Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...

 web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

s are skinnable because they take advantage of a cross-platform toolkit.

Standard interface

Of course, it is also possible to change the standard interface. Some platforms have support for this built in, including most using the X Window System

X Window System

The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...

. For those that do not, there are usually programs that can add the functionality, like WindowBlinds

WindowBlinds

WindowBlinds is a computer program that allows users to skin the Windows graphical user interface. It has been developed by Stardock since 1998, and is the most popular component of their flagship software suite, Object Desktop. It is also available separately, and as an ActiveX/COM component...

 for Microsoft Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 and ShapeShifter

ShapeShifter

ShapeShifter is an Application Enhancer plugin for Mac OS X developed by Unsanity that allows the user to make system-wide modifications to the appearance of the operating system's graphical interface by applying GUI skins through “injection” into running code and without modifying system files,...

 for Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

.

Model–view–controller

Skinning is typically implemented with a model–view–controller architecture, which allows for a flexible structure in which the interface is independent from and indirectly linked to application functionality, so the GUI can be easily customized. This allows the user to select or design a different skin at will, and also allows for more deep changes in the position and function of the interface elements

Elements of graphical user interfaces

Graphical user interfaces, also known as GUIs, offer a consistent visual language to represent information stored in computers. This makes it easier for people with little computer skills to work with and use computer software....

.

Pros and cons

The benefit of skinning in user interfaces is disputed. While some find it useful or pleasant to be able to change the appearance of software they use, a changed appearance can complicate technical support

Technical support

Technical support or tech support refers to a range of services by which enterprises provide assistance to users of technology products such as mobile phones, televisions, computers, software products or other electronic or mechanical goods...

 and training. A user interface that has been extensively customized by one person may appear completely unfamiliar to another who knows the software under a different appearance. It is often said by usability

Usability

Usability is the ease of use and learnability of a human-made object. The object of use can be a software application, website, book, tool, machine, process, or anything a human interacts with. A usability study may be conducted as a primary job function by a usability analyst or as a secondary job...

 practitioners that this flexibility "requires the user to be an expert interaction designer" to tailor the software for best use.

Websites

Many websites are also skinnable, particularly those which provide some social

Social

The term social refers to a characteristic of living organisms...

 capabilities. Again, some sites offer skins that make primarily cosmetic changes, while some — such as H2G2

H2g2

h2g2 is a British-based collaborative online encyclopedia project engaged in the construction of, in its own words, "an unconventional guide to life, the universe, and everything", in the spirit of the fictional publication The Hitchhiker's Guide to the Galaxy from the science fiction comedy series...

 — allow major changes to the layout of pages. As with standalone software interfaces, this is facilitated by the underlying technology of the website — the use of XML

XML

Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 and XSLT

XSLT

XSLT is a declarative, XML-based language used for the transformation of XML documents. The original document is not changed; rather, a new document is created based on the content of an existing one. The new document may be serialized by the processor in standard XML syntax or in another format,...

, for instance, facilitates major changes of layout, while CSS

Cascading Style Sheets

Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...

 can be used to easily produce different visual styles. There are even sites for skinning things such as Halo: Combat Evolved

Halo: Combat Evolved

Halo: Combat Evolved, frequently referred to as Halo: CE, or Halo 1, is a first-person shooter video game developed by Bungie and published by Microsoft Game Studios. The first game of the Halo franchise, it was released on November 15, 2001 as a launch title for the Xbox gaming system, and is...

for the PC such as Halo 1 Skins