Editing User interface (section)

{{Short description|Means by which a user interacts with and controls a machine}}
{{About||the boundary between computer systems|Interface (computing)}}
{{Redirect|Man–machine interface|other uses|UI (disambiguation)|the communications protocol|GSM Man-Machine Interface}}
{{Use dmy dates|date=July 2022}}
[[File:XFCE-4.10-Desktop.png|thumb|The [[Xfce]] desktop environment offers a [[graphical user interface]] following the [[desktop metaphor]]. ]]
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 system]]s, hand [[tool]]s, [[heavy machinery]] operator controls and [[Unit operation|process]] controls. The design considerations applicable when creating user interfaces are related to, or involve such disciplines as, [[ergonomics]] and [[psychology]].

Generally, the goal of [[user interface design]] is to produce a user interface that makes it easy, efficient, and enjoyable (user-friendly) to operate a machine in the way which produces the desired result (i.e. maximum [[usability]]). This generally means that the operator needs to provide minimal input to achieve the desired output, and also that the machine minimizes undesired outputs to the user.

User interfaces are composed of one or more layers, including a '''human–machine interface''' ('''HMI''') that typically interfaces machines with physical [[input device|input hardware]] (such as keyboards, mice, or game pads) and output hardware (such as [[computer monitor]]s, speakers, and [[printer (computing)|printer]]s). A device that implements an HMI is called a [[human interface device]] (HID). User interfaces that dispense with the physical movement of body parts as an intermediary step between the brain and the machine use no input or output devices except electrodes alone; they are called [[brain–computer interface]]s (BCIs) or [[brain–machine interface]]s (BMIs).

Other terms for human–machine interfaces are '''man–machine interface''' ('''MMI''') and, when the machine in question is a computer, '''human–computer interface'''. Additional UI layers may interact with one or more human senses, including: tactile UI ([[Somatosensory system|touch]]), visual UI ([[Visual perception|sight]]), auditory UI ([[Hearing|sound]]), olfactory UI ([[Olfaction|smell]]), equilibria UI ([[Sense of balance|balance]]), and gustatory UI ([[taste]]).

'''Composite user interfaces''' ('''CUIs''') are UIs that interact with two or more senses. The most common CUI is a ''[[graphical user interface]]'' (GUI), which is composed of a tactile UI and a visual UI capable of displaying [[graphics]]. When sound is added to a GUI, it becomes a ''multimedia user interface'' (MUI). There are three broad categories of CUI: ''standard'', ''virtual'' and ''augmented''. Standard CUI use standard human interface devices like keyboards, mice, and computer monitors. When the CUI blocks out the real world to create a [[virtual reality]], the CUI is virtual and uses a ''virtual reality interface''. When the CUI does not block out the real world and creates [[augmented reality]], the CUI is augmented and uses an ''augmented reality interface''. When a UI interacts with all human senses, it is called a qualia interface, named after the theory of [[qualia]].{{citation needed|date=January 2022}} CUI may also be classified by how many senses they interact with as either an X-sense virtual reality interface or X-sense augmented reality interface, where X is the number of senses interfaced with. For example, a [[Smell-O-Vision]] is a 3-sense (3S) Standard CUI with visual display, sound and smells; when ''virtual reality interfaces'' interface with smells and touch it is said to be a 4-sense (4S) virtual reality interface; and when ''augmented reality interfaces'' interface with smells and touch it is said to be a 4-sense (4S) augmented reality interface.