Graphical user interface

Last updated

The GUI ( /ˌjuːˈ/ JEE-yoo-EYE [1] [Note 1] or /ˈɡi/ [2] GOO-ee), 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, instead of text-based UIs, typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of CLIs (command-line interfaces), [3] [4] [5] which require commands to be typed on a computer keyboard.


The actions in a GUI are usually performed through direct manipulation of the graphical elements. [6] [7] [8] Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. The term GUI tends not to be applied to other lower-display resolution types of interfaces, such as video games (where HUD (head-up display) [9] is preferred), or not including flat screens like volumetric displays [10] because the term is restricted to the scope of 2D display screens able to describe generic information, in the tradition of the computer science research at the Xerox Palo Alto Research Center.

GUI and interaction design

The GUI is presented (displayed) on the computer screen. It is the result of processed user input and usually the main interface for human-machine interaction. The touch UIs popular on small mobile devices are an overlay of the visual output to the visual input. Linux kernel INPUT OUPUT evdev gem USB framebuffer.svg
The GUI is presented (displayed) on the computer screen. It is the result of processed user input and usually the main interface for human-machine interaction. The touch UIs popular on small mobile devices are an overlay of the visual output to the visual input.

Designing the visual composition and temporal behavior of a GUI is an important part of software application programming in the area of human–computer interaction. Its goal is to enhance the efficiency and ease of use for the underlying logical design of a stored program, a design discipline named usability . Methods of user-centered design are used to ensure that the visual language introduced in the design is well-tailored to the tasks.

The visible graphical interface features of an application are sometimes referred to as chrome or GUI (pronounced gooey). [11] [12] [13] Typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to the kind of data they hold. The widgets of a well-designed interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows flexible structures in which the interface is independent of and indirectly linked to application functions, so the GUI can be customized easily. This allows users to select or design a different skin at will, and eases the designer's work to change the interface as user needs evolve. Good GUI design relates to users more, and to system architecture less. Large widgets, such as windows, usually provide a frame or container for the main presentation content such as a web page, email message, or drawing. Smaller ones usually act as a user-input tool.

A GUI may be designed for the requirements of a vertical market as application-specific GUIs. Examples include automated teller machines (ATM), point of sale (POS) touchscreens at restaurants, [14] self-service checkouts used in a retail store, airline self-ticket and check-in, information kiosks in a public space, like a train station or a museum, and monitors or control screens in an embedded industrial application which employ a real-time operating system (RTOS).

Cell phones and handheld game systems also employ application specific touchscreen GUIs. Newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations.



Layers of a GUI based on a windowing system Schema of the layers of the graphical user interface.svg
Layers of a GUI based on a windowing system

A GUI uses a combination of technologies and devices to provide a platform that users can interact with, for the tasks of gathering and producing information.

A series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with and use computer software. The most common combination of such elements in GUIs is the windows, icons, text fields, canvases, menus, pointer (WIMP) paradigm, especially in personal computers. [15]

The WIMP style of interaction uses a virtual input device to represent the position of a pointing device's interface, most often a mouse, and presents information organized in windows and represented with icons. Available commands are compiled together in menus, and actions are performed making gestures with the pointing device. A window manager facilitates the interactions between windows, applications, and the windowing system. The windowing system handles hardware devices such as pointing devices, graphics hardware, and positioning of the pointer.

In personal computers, all these elements are modeled through a desktop metaphor to produce a simulation called a desktop environment in which the display represents a desktop, on which documents and folders of documents can be placed. Window managers and other software combine to simulate the desktop environment with varying degrees of realism.

Entries may appear in a list to make space for text and details, or in a grid for compactness and larger icons with little space underneath for text. Variations inbetween exist, such as a list with multiple columns of items and a grid of items with rows of text extending sideways from the icon. [16]

Multi-row and multi-column layouts commonly found on the web are "shelf" and "waterfall". The former is found on image search engines, where images appear with a fixed height but variable length, and is typically implemented with the CSS property and parameter display: inline-block;. A waterfall layout found on Imgur and Tweetdeck with fixed width but variable height per item is usually implemented by specifying column-width:.

Post-WIMP interface

Smaller app mobile devices such as personal digital assistants (PDAs) and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space and available input devices. Applications for which WIMP is not well suited may use newer interaction techniques, collectively termed post-WIMP UIs. [17]

As of 2011, some touchscreen-based operating systems such as Apple's iOS (iPhone) and Android use the class of GUIs named post-WIMP. These support styles of interaction using more than one finger in contact with a display, which allows actions such as pinching and rotating, which are unsupported by one pointer and mouse. [18]


Human interface devices, for the efficient interaction with a GUI include a computer keyboard, especially used together with keyboard shortcuts, pointing devices for the cursor (or rather pointer) control: mouse, pointing stick, touchpad, trackball, joystick, virtual keyboards, and head-up displays (translucent information devices at the eye level).

There are also actions performed by programs that affect the GUI. For example, there are components like inotify or D-Bus to facilitate communication between computer programs.


Early efforts

Ivan Sutherland developed Sketchpad in 1963, widely held as the first graphical computer-aided design program. It used a light pen to create and manipulate objects in engineering drawings in realtime with coordinated graphics. In the late 1960s, researchers at the Stanford Research Institute, led by Douglas Engelbart, developed the On-Line System (NLS), which used text-based hyperlinks manipulated with a then-new device: the mouse. (A 1968 demonstration of NLS became known as "The Mother of All Demos.") In the 1970s, Engelbart's ideas were further refined and extended to graphics by researchers at Xerox PARC and specifically Alan Kay, who went beyond text-based hyperlinks and used a GUI as the main interface for the Smalltalk programming language, which ran on the Xerox Alto computer, released in 1973. Most modern general-purpose GUIs are derived from this system.

The Xerox PARC GUI consisted of graphical elements such as windows, menus, radio buttons, and check boxes. The concept of icons was later introduced by David Canfield Smith, who had written a thesis on the subject under the guidance of Kay. [19] [20] [21] The PARC GUI employs a pointing device along with a keyboard. These aspects can be emphasized by using the alternative term and acronym for windows, icons, menus, pointing device (WIMP). This effort culminated in the 1973 Xerox Alto, the first computer with a GUI, though the system never reached commercial production.

The first commercially available computer with a GUI was 1979 PERQ workstation, manufactured by Three Rivers Computer Corporation. Its design was heavily influenced by the work at Xerox PARC. In 1981, Xerox eventually commercialized the Alto in the form of a new and enhanced system – the Xerox 8010 Information System – more commonly known as the Xerox Star. [22] [23] These early systems spurred many other GUI efforts, including Lisp machines by Symbolics and other manufacturers, the Apple Lisa (which presented the concept of menu bar and window controls) in 1983, the Apple Macintosh 128K in 1984, and the Atari ST with Digital Research's GEM, and Commodore Amiga in 1985. Visi On was released in 1983 for the IBM PC compatible computers, but was never popular due to its high hardware demands. [24] Nevertheless, it was a crucial influence on the contemporary development of Microsoft Windows. [25]

Apple, Digital Research, IBM and Microsoft used many of Xerox's ideas to develop products, and IBM's Common User Access specifications formed the basis of the GUIs used in Microsoft Windows, IBM OS/2 Presentation Manager, and the Unix Motif toolkit and window manager. These ideas evolved to create the interface found in current versions of Microsoft Windows, and in various desktop environments for Unix-like operating systems, such as macOS and Linux. Thus most current GUIs have largely common idioms.

An Apple Lisa (1983) demonstrating LisaOS, Apple Computer's first commercially available GUI. Apple Lisa Computer.jpg
An Apple Lisa (1983) demonstrating LisaOS, Apple Computer's first commercially available GUI.


HP LX System Manager running on a HP 200LX. Hewlett Packard 200LX.jpg
HP LX System Manager running on a HP 200LX.

GUIs were a hot topic in the early 1980s. The Apple Lisa was released in 1983, and various windowing systems existed for DOS operating systems (including PC GEM and PC/GEOS). Individual applications for many platforms presented their own GUI variants. [26] Despite the GUIs advantages, many reviewers questioned the value of the entire concept, [27] citing hardware limits, and problems in finding compatible software.

In 1984, Apple released a television commercial which introduced the Apple Macintosh during the telecast of Super Bowl XVIII by CBS, [28] with allusions to George Orwell's noted novel Nineteen Eighty-Four . The goal of the commercial was to make people think about computers, identifying the user-friendly interface as a personal computer which departed from prior business-oriented systems, [29] and becoming a signature representation of Apple products. [30]

Windows 95, accompanied by an extensive marketing campaign, [31] was a major success in the marketplace at launch and shortly became the most popular desktop operating system. [32]

In 2007, with the iPhone [33] and later in 2010 with the introduction of the iPad, [34] Apple popularized the post-WIMP style of interaction for multi-touch screens, and those devices were considered to be milestones in the development of mobile devices. [35] [36]

The GUIs familiar to most people as of the mid-late 2010s are Microsoft Windows, macOS, and the X Window System interfaces for desktop and laptop computers, and Android, Apple's iOS, Symbian, BlackBerry OS, Windows Phone/Windows 10 Mobile, Tizen, WebOS, and Firefox OS for handheld (smartphone) devices. [37] [38]

Comparison to other interfaces

Command-line interfaces

A modern CLI Bash screenshot.png
A modern CLI

Since the commands available in command line interfaces can be many, complex operations can be performed using a short sequence of words and symbols. Custom functions may be used to facilitate access to frequent actions. Command-line interfaces are more lightweight, as they only recall information necessary for a task; for example, no preview thumbnails or graphical rendering of web pages. This allows greater efficiency and productivity once many commands are learned. [3] But reaching this level takes some time because the command words may not be easily discoverable or mnemonic. Also, using the command line can become slow and error-prone when users must enter long commands comprising many parameters or several different filenames at once. However, windows, icons, menus, pointer (WIMP) interfaces present users with many widgets that represent and can trigger some of the system's available commands.

GUIs can be made quite hard when dialogs are buried deep in a system or moved about to different places during redesigns. Also, icons and dialog boxes are usually harder for users to script.

WIMPs extensively use modes, as the meaning of all keys and clicks on specific positions on the screen are redefined all the time. Command-line interfaces use modes only in limited forms, such as for current directory and environment variables.

Most modern operating systems provide both a GUI and some level of a CLI, although the GUIs usually receive more attention.

GUI wrappers

GUI wrappers find a way around the command-line interface versions (CLI) of (typically) Linux and Unix-like software applications and their text-based UIs or typed command labels. While command-line or text-based applications allow users to run a program non-interactively, GUI wrappers atop them avoid the steep learning curve of the command-line, which requires commands to be typed on the keyboard. By starting a GUI wrapper, users can intuitively interact with, start, stop, and change its working parameters, through graphical icons and visual indicators of a desktop environment, for example. Applications may also provide both interfaces, and when they do the GUI is usually a WIMP wrapper around the command-line version. This is especially common with applications designed for Unix-like operating systems. The latter used to be implemented first because it allowed the developers to focus exclusively on their product's functionality without bothering about interface details such as designing icons and placing buttons. Designing programs this way also allows users to run the program in a shell script.

Three-dimensional graphical user interface

Many environments and games use the methods of 3D graphics to project 3D GUI objects onto the screen. The use of 3D graphics has become increasingly common in mainstream operating systems (ex. Windows Aero, and Aqua (MacOS)) to create attractive interfaces, termed eye candy (which includes, for example, the use of drop shadows underneath windows and the cursor), or for functional purposes only possible using three dimensions. For example, user switching is represented by rotating a cube with faces representing each user's workspace, and window management is represented via a Rolodex-style flipping mechanism in Windows Vista (see Windows Flip 3D). In both cases, the operating system transforms windows on-the-fly while continuing to update the content of those windows.

The GUI is usually WIMP-based, although occasionally other metaphors surface, such as those used in Microsoft Bob, 3dwm, File System Navigator, File System Visualizer, 3D Mailbox, [39] [40] and GopherVR. Zooming (ZUI) is a related technology that promises to deliver the representation benefits of 3D environments without their usability drawbacks of orientation problems and hidden objects. In 2006, Hillcrest Labs introduced the first ZUI for television. [41] Other innovations include the menus on the PlayStation 2, the menus on the Xbox, Sun's Project Looking Glass, Metisse, which was similar to Project Looking Glass, [42] BumpTop, where users can manipulate documents and windows with realistic movement and physics as if they were physical documents, Croquet OS, which is built for collaboration, [43] and compositing window managers such as Enlightenment and Compiz. Augmented reality and virtual reality also make use of 3D GUI elements. [44]

In science fiction

3D GUIs have appeared in science fiction literature and films, even before certain technologies were feasible or in common use. [45]

See also


  1. "UI" by itself is still usually pronounced /ˌjˈ/ yoo-EYE.

Related Research Articles

<span class="mw-page-title-main">Context menu</span> User interface element

A context menu is a menu in a graphical user interface (GUI) that appears upon user interaction, such as a right-click mouse operation. A context menu offers a limited set of choices that are available in the current state, or context, of the operating system or application to which the menu belongs. Usually the available choices are actions related to the selected object. From a technical point of view, such a context menu is a graphical control element.

<span class="mw-page-title-main">History of the graphical user interface</span>

The history of the graphical user interface, understood as the use of graphic icons and a pointing device to control a computer, covers a five-decade span of incremental refinements, built on some constant core principles. Several vendors have created their own windowing systems based on independent code, but with basic elements in common that define the WIMP "window, icon, menu and pointing device" paradigm.

<span class="mw-page-title-main">User interface</span> Means by which a user interacts with and controls a machine

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 from the human end, while the machine simultaneously feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls and process controls. The design considerations applicable when creating user interfaces are related to, or involve such disciplines as, ergonomics and psychology.

In computing, a desktop environment (DE) is an implementation of the desktop metaphor made of a bundle of programs running on top of a computer operating system that share a common graphical user interface (GUI), sometimes described as a graphical shell. The desktop environment was seen mostly on personal computers until the rise of mobile computing. Desktop GUIs help the user to easily access and edit files, while they usually do not provide access to all of the features found in the underlying operating system. Instead, the traditional command-line interface (CLI) is still used when full control over the operating system is required.

<span class="mw-page-title-main">Windowing system</span> Software that manages separately different parts of display screens

In computing, a windowing system is software that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP paradigm for a user interface.

In computing, a window is a graphical control element. It consists of a visual area containing some of the graphical user interface of the program it belongs to and is framed by a window decoration. It usually has a rectangular shape that can overlap with the area of other windows. It displays the output of and may allow input to one or more processes.

<span class="mw-page-title-main">Desktop metaphor</span> Concept used on desktop computer graphical user interfaces

In computing, the desktop metaphor is an interface metaphor which is a set of unifying concepts used by graphical user interfaces to help users interact more easily with the computer. The desktop metaphor treats the computer monitor as if it is the top of the user's desk, upon which objects such as documents and folders of documents can be placed. A document can be opened into a window, which represents a paper copy of the document placed on the desktop. Small applications called desk accessories are also available, such as a desk calculator or notepad, etc.

In computing, an icon is a pictogram or ideogram displayed on a computer screen in order to help the user navigate a computer system. The icon itself is a quickly comprehensible symbol of a software tool, function, or a data file, accessible on the system and is more like a traffic sign than a detailed illustration of the actual entity it represents. It can serve as an electronic hyperlink or file shortcut to access the program or data. The user can activate an icon using a mouse, pointer, finger, or recently voice commands. Their placement on the screen, also in relation to other icons, may provide further information to the user about their usage. In activating an icon, the user can move directly into and out of the identified function without knowing anything further about the location or requirements of the file or code.

<span class="mw-page-title-main">WIMP (computing)</span> Style of human-computer interaction

In human–computer interaction, WIMP stands for "windows, icons, menus, pointer", denoting a style of interaction using these elements of the user interface. Other expansions are sometimes used, such as substituting "mouse" and "mice" for menus, or "pull-down menu" and "pointing" for pointer.

Common User Access (CUA) is a standard for user interfaces to operating systems and computer programs. It was developed by IBM and first published in 1987 as part of their Systems Application Architecture. Used originally in the MVS/ESA, VM/CMS, OS/400, OS/2 and Microsoft Windows operating systems, parts of the CUA standard are now implemented in programs for other operating systems, including variants of Unix. It is also used by Java AWT and Swing.

<span class="mw-page-title-main">Window manager</span> Type of system software

A window manager is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface. Most window managers are designed to help provide a desktop environment. They work in conjunction with the underlying graphical system that provides required functionality—support for graphics hardware, pointing devices, and a keyboard—and are often written and created using a widget toolkit.

The following outline is provided as an overview of and topical guide to human–computer interaction:

<span class="mw-page-title-main">Virtual desktop</span> User interfaces describe ways in which virtual space of a computers desktop is expanded

In computing, a virtual desktop is a term used with respect to user interfaces, usually within the WIMP paradigm, to describe ways in which the virtual space of a computer's desktop environment is expanded beyond the physical limits of the screen's display area through the use of software. This compensates limits of the desktop area and is helpful in reducing clutter of running graphical applications.

In human–computer interaction, a cursor is an indicator used to show the current position on a computer monitor or other display device that will respond to text input.

<span class="mw-page-title-main">Shell (computing)</span> Computer program that exposes an operating systems services to a human user or other programs

In computing, a shell is a computer program that exposes an operating system's services to a human user or other programs. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. It is named a shell because it is the outermost layer around the operating system.

A menu bar is a graphical control element which contains drop-down menus.

In user interface design, an interface metaphor is a set of user interface visuals, actions and procedures that exploit specific knowledge that users already have of other domains. The purpose of the interface metaphor is to give the user instantaneous knowledge about how to interact with the user interface. They are designed to be similar to physical entities but also have their own properties. They can be based on an activity, an object (skeuomorph), or a combination of both and work with users' familiar knowledge to help them understand 'the unfamiliar', and placed in the terms so the user may better understand.

Intuition is the native windowing system and user interface (UI) engine of AmigaOS. It was developed almost entirely by RJ Mical. Intuition should not be confused with Workbench, the AmigaOS desktop environment and spatial file manager, which relies on Intuition for handling windows and input events. Workbench uses Intuition to produce displays and AmigaDOS to interact with filing system: AmigaDOS is built on Exec.

In computing, post-WIMP comprises work on user interfaces, mostly graphical user interfaces, which attempt to go beyond the paradigm of windows, icons, menus and a pointing device, i.e. WIMP interfaces.


  1. Wells, John (2009). Longman Pronunciation Dictionary (3rd ed.). Pearson Longman. ISBN   978-1-4058-8118-0.
  2. "How to pronounce GUI in English". Retrieved 2020-04-03.
  3. 1 2 "Command line vs. GUI". Retrieved 2020-04-03.
  4. MSCOM (2007-03-12). "The GUI versus the Command Line: Which is better? (Part 1)". Operations. Microsoft Docs . Retrieved 2021-11-07.{{cite web}}: External link in |department= (help)
  5. MSCOM (2007-03-26). "The GUI versus the Command Line: Which is better? (Part 2)". Operations. Microsoft Docs . Retrieved 2021-11-07.{{cite web}}: External link in |department= (help)
  6. "Graphical user interface". ScienceDaily. Retrieved 2019-05-09.
  7. Levy, Steven. "Graphical User Interface (GUI)". Retrieved 2019-06-12.
  8. "GUI". PC Magazine Encyclopedia. Retrieved 2019-06-12.
  9. Greg Wilson (2006). "Off with Their HUDs!: Rethinking the Heads-Up Display in Console Game Design". Gamasutra . Archived from the original on January 19, 2010. Retrieved February 14, 2006.
  10. "GUI definition". Linux Information Project. October 1, 2004. Retrieved 12 November 2008.
  11. "chrome". Retrieved 2020-04-03.
  12. Jakob Nielsen (January 29, 2012). "Browser and GUI Chrome". Nngroup. Archived from the original on August 25, 2012. Retrieved May 20, 2012.
  13. Martinez, Wendy L. (2011-02-23). "Graphical user interfaces: Graphical user interfaces". Wiley Interdisciplinary Reviews: Computational Statistics. 3 (2): 119–133. doi:10.1002/wics.150. S2CID   60467930.
  14. The ViewTouch restaurant system by Giselle Bisson
  15. "What is a graphical user interface (GUI)?". IONOS Digitalguide. Retrieved 2022-02-25.
  16. Babich, Nick (30 May 2020). "Mobile UX Design: List View and Grid View". Medium. Retrieved 4 September 2021.
  18. Reality-Based Interaction: A Framework for Post-WIMP Interfaces
  19. Lieberman, Henry. "A Creative Programming Environment, Remixed", MIT Media Lab, Cambridge.
  20. Salha, Nader. "Aesthetics and Art in the Early Development of Human-Computer Interfaces" Archived 2020-08-07 at the Wayback Machine , October 2012.
  21. Smith, David. "Pygmalion: A Creative Programming Environment", 1975.
  22. The first GUIs
  23. Xerox Star user interface demonstration, 1982
  24. "VisiCorp Visi On". The Visi On product was not intended for the home user. It was designed and priced for high-end corporate workstations. The hardware it required was quite a bit for 1983. It required a minimum of 512k of ram and a hard drive (5 megs of space).
  25. A Windows Retrospective, PC Magazine Jan 2009. Ziff Davis. January 2009.
  26. "Magic Desk I for Commodore 64".
  27. Sandberg-Diment, Erik (1984-12-25). "Value of Windowing is Questioned". The New York Times.
  28. Friedman, Ted (October 1997). "Apple's 1984: The Introduction of the Macintosh in the Cultural History of Personal Computers". Archived from the original on October 5, 1999.
  29. Friedman, Ted (2005). "Chapter 5: 1984". Electric Dreams: Computers in American Culture. New York University Press. ISBN   978-0-8147-2740-9 . Retrieved October 6, 2011.
  30. Grote, Patrick (October 29, 2006). "Review of Pirates of Silicon Valley Movie". Archived from the original on November 7, 2006. Retrieved January 24, 2014.
  31. Washington Post (August 24, 1995). "With Windows 95's Debut, Microsoft Scales Heights of Hype". Washington Post. Retrieved November 8, 2013.
  32. "Computers | Timeline of Computer History | Computer History Museum". Retrieved 2017-04-02.
  33. Mather, John. iMania, Ryerson Review of Journalism , (February 19, 2007) Retrieved February 19, 2007
  34. "the iPad could finally spark demand for the hitherto unsuccessful tablet PC" --Eaton, Nick The iPad/tablet PC market defined? Archived 2011-02-01 at the Wayback Machine , Seattle Post-Intelligencer, 2010
  35. Bright, Peter Ballmer (and Microsoft) still doesn't get the iPad, Ars Technica, 2010
  36. "The iPad's victory in defining the tablet: What it means". InfoWorld . 2011-07-05.
  37. Hanson, Cody W. (2011-03-17). "Chapter 2: Mobile Devices in 2011". Library Technology Reports. 47 (2): 11–23. ISSN   0024-2586.
  38. "What is a Graphical User Interface? Definition and FAQs | OmniSci". Retrieved 2022-01-26.
  39. "3D Mailbox - 3-Dimensional Email Software. Bring e-mail to life! Email just got cool and fun". Archived from the original on 2019-07-21. Retrieved 2022-07-14.
  40. "3D Mailbox". Retrieved 2022-07-14.
  41. November 11, 2006. Dan Moren. CES Unveiled@NY ‘07: Point and click coming to set-top boxes? Archived 2011-11-08 at the Wayback Machine
  42. "Metisse - New Looking Glass Alternative". 29 June 2004. Retrieved 2 July 2020.
  43. Smith, David A.; Kay, Alan; Raab, Andreas; Reed, David P. "Croquet – A Collaboration System Architecture" (PDF). Archived from the original (PDF) on 2007-09-27. Retrieved 2022-09-17. The efforts at Xerox PARC under the leadership of Alan Kay that drove the development of [...] powerful bit-mapped display based user interfaces was key. In some ways, all we are doing here is extending this model to 3D and adding a new robust object collaboration model.
  44. Purwar, Sourabh (2019-03-04). "Designing User Experience for Virtual Reality (VR) applications". Medium. Retrieved 2022-05-06.
  45. Dayton, Tom. "Object-Oriented GUIs are the Future". OpenMCT Blog. Archived from the original on 10 August 2014. Retrieved 23 August 2012.