software design Software design is the process by which an agent creates a specification of a software artifact intended to accomplish goals, using a set of primitive components and subject to constraints. Software design may refer to either "all the activity ...

, the look and feel of a

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

comprises aspects of its design, including elements such as colors, shapes, layout, and

typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are list of type ...

s (the "look"), as well as the behavior of dynamic elements such as buttons, boxes, and menus (the "feel"). The term can also refer to aspects of a non-graphical

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...

(such as a

command-line interface A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

), as well as to aspects of an

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

– mostly to parts of an API that are not related to its functional properties. The term is used in reference to both

software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...

and

website A website (also written as a web site) is a collection of web pages and related content that is identified by a common domain name and published on at least one web server. Examples of notable websites are Google Search, Google, Facebook, Amaz ...

s. Look and feel applies to other products. In documentation, for example, it refers to the graphical layout (document size, color, font, etc.) and the writing style. In the context of equipment, it refers to consistency in controls and displays across a product line. Look and feel in

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s serves two general purposes. First, it provides

brand A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create an ...

ing, helping to identify a set of products from one company. Second, it increases ease of use, since users will become familiar with how one product functions (looks, reads, etc.) and can translate their experience to other products with the same look and feel.

In widget toolkits

Contrary to

s, for which look and feel is a part of the product identification,

widget toolkit A widget toolkit, widget library, GUI toolkit, or UX library is a library or a collection of libraries containing a set of graphical control elements (called ''widgets'') used to construct the graphical user interface (GUI) of programs. Most widg ...

s often allow users to specialize their application look and feel, by deriving the default look and feel of the toolkit, or by completely defining their own. This specialization can go from

skinning Skinning is the act of skin removal. The process is done by humans to animals, mainly as a means to prepare the meat beneath for cooking and consumption, or to harvest the skin for making fur clothing or tanning it to make leather. The skin ...

(that only deals with the look, or visual appearance of the graphical control elements) to completely specializing the way the user interacts with the software (that is, the feel). The definition of the look and feel to associate with the application is often done at initialization, but some Widget toolkits, such as the Swing widget toolkit that is part of the

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

, allow users to change the look and feel at runtime (see

Pluggable look and feel Pluggable look and feel is a mechanism used in the Java Swing widget toolkit allowing to change the look and feel of the graphical user interface at runtime. Swing allows an application to specialize the look and feel of widgets by modifying the ...

). Some examples of Widget toolkits that support setting a specialized look and feel are: *

XUL XUL ( ), which stands for XML User Interface Language, is a user interface markup language developed by Mozilla. XUL is an XML dialect for writing graphical user interfaces, enabling developers to write user interface elements in a manner sim ...

(XML User Interface Language): The look and feel of the user interface can be specialized in a

CSS Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML (including XML dialects such as SVG, MathML or XHTML). CSS is a cornerstone techno ...

file associated with the XUL definition files. Properties that can be specialized from the default are, for example, background or foreground colors of widgets, fonts, size of widgets, and so on. * Swing supports specializing the look and feel of widgets by deriving from the default, another existing one, creating one from scratch, or, beginning with J2SE 5.0, in an

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable ...

property file called

synth A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and ...

(skinnable look and feel).

Lawsuits

Some companies try to assert

copyright A copyright is a type of intellectual property that gives its owner the exclusive right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time. The creative work may be in a literary, artistic, education ...

trade dress Trade dress is the characteristics of the visual appearance of a product or its packaging (or even the design of a building) that signify the source of the product to consumers. Trade dress is an aspect of trademark law, which is a form of intelle ...

over their look and feel. The ''

Broderbund v. Unison ''Broderbund Software Inc. v. Unison World, Inc.'', 648 F. Supp. 1127, 1133 (N.D. Cal. 1986), was a United States District Court for the Northern District of California software case, initially important in determining how U.S. copyright law appli ...

'' (1986) case was an early

software copyright Software copyright is the application of copyright in law to machine-readable software. While many of the legal principles and policy debates concerning software copyright have close parallels in other domains of copyright law, there are a number o ...

case that attempted to apply U.S. copyright law to the look and feel presented by a software product. In 1987 Lotus sued Paperback Software and Mosaic for copyright infringement, false and misleading advertising, and

unfair competition Unfair may refer to: * Double Taz and Double LeBron James in multiverses ''fair''; unfairness or injustice * ''Unfair'' (drama), Japanese television series * '' Unfair: The Movie'' * Unfair (song), a song by South Korean boy group EXO