2Input TechniquesAn interaction technique, user interface technique or input technique is a combination of hardware and software elements that provides a way for computer users toaccomplish a single task.For example, one can go back to thepreviously visited page on a Web browserby either clicking a button, pressing a key,performing a mouse gesture or utteringa speech command. It is a key concept inhuman-computer interaction.Fold n' Drop, a crossing-based input (interaction) technique for dragging and dropping files between overlapping windows.Crossing-based interfaces are graphical user interfaces that use crossing gestures instead of, or in complement to, pointing.
3DefinitionAn input(interaction) technique is a way of using a physical input/output device to perform a generic task in a human-computer dialogue.A more recent variation is:An input(interaction) technique is the fusion of input and output, consisting of all software and hardware elements, that provides a way for the user to accomplish a task.
4Continue… The computing view From the computer's perspective, an input(interaction) techniqueinvolves:One or several input devices that capture user input,One or several output devices that display user feedback,A piece of code that:produces user feedback based on user input and the system's state,interprets user input into commands the computer can understand.Consider for example the process of deleting a file using a contextual menu. This assumes the existence of a mouse (input device), a screen (output device), and a piece of code that paints a menu and updates its selection (user feedback) and sends a command to the file system when the user clicks on the "delete" item (interpretation).
5Continue… The user's view From the user's perspective, an input(interaction) technique is a way to perform a simple computing task and can be described by the way of user instructions or usage scenarios.For example "right-click on the file you want to delete, then click on the delete item".The designer's viewFrom the user interface designer's perspective, an interaction technique is a simple solution to a well-defined user interface design problem. Interaction techniques as conceptual ideas can be refined, extended, modified and combined. For example, pie menus are a radial variant of contextual menus. Marking menus combine pie menus with gestures.In computer interface design, a pie menu (also known as a radial menu or marking menu) is a circular context menu where selection depends on direction.A pie menu
6Level of granularityInteraction techniques are usually fine-grained entities.For example, a desktop environment is too complex to be an interaction technique, whereas Exposé fits the common intuitive understanding of the term perfectly well.Exposé is a feature of the Mac OS X operating system.Screenshot of the Exposé feature in Mac OS X .Developer(s) Apple, IncInitial release October (Mac OS X v10.3 "Panther")Type Window management tool
7Continue… In general, a user interface can be seen as a combination of many interaction techniques, some of which are notnecessarily as well-defined as widgets.In computer programming, a widget (or control) is an element of agraphical user interface (GUI) that displays an information arrangementchangeable by the user, such as a window or a text box.Various widgets
8Interaction tasks and domain objects An interaction task is "the unit of an entry of information by the user" , such as entering a piece of text, issuing a command, or specifying a 2D position. A similar concept is that of domain object, which is a piece of application data that can be manipulated by the user.Interaction techniques are the glue between physical I/O devices and interaction tasks or domain objects. Different types of interaction techniques can be used to map a specific device to a specific domain object.For example, different gesture alphabets exist for pen-based text input.In general, the less compatible the device is with the domain object, the more complex the interaction technique.For example, using a mouse to specify a 2D point involves a trivial interaction technique, whereas using a mouse to rotate a 3D object requires more creativity to design the technique and more lines of code to implement it.
9Continue…A current trend is to avoid complex interaction techniques by matching physical devices with the task as close as possible, such as exemplified by the field of tangible computing. But this is not always a feasible solution. Furthermore, device/task incompatibilities are unavoidable in computer accessibility, where a single switch can be used to control the whole computer environment.A tangible user interface (TUI) is a user interface in which a person interacts with digital information through the physical environment.
10Interaction styleInteraction techniques that share the same metaphor or design principles can be seen as belonging to the same interaction style.General examples are command line and direct manipulation user interfaces.A command-line interface (CLI) is a mechanism for interacting with a computer operating system or software by typing commands to perform specific tasks.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.The folders and the file cabinet representation of the file system of an operating system is an example of Interface metaphor.Another example is the tree view representation of a file system, as in a file manager that helps a user to use it, given some previous knowledge of recursive structures.
11Continue…Direct manipulation is a human-computer interaction style which involves continuous representation of objects of interest, and rapid, reversible, incremental actions and feedback. The intention is to allow a user to directly manipulate objects presented to them, using actions that correspond at least loosely to the physical world. Having real-world metaphors for objects and actions can make it easier for a user to learn and use an interface (some might say that the interface is more natural or intuitive), and rapid, incremental feedback allows a user to make fewer errors and complete tasks in less time, because they can see the results of an action before completing the action.An example of direct-manipulation is resizing a graphical shape, such as a rectangle, by dragging its corners or edges with a mouse.The concept of Interaction Styles refers to all the ways the user can communicate or otherwise interact with the computer system.
12Visualization technique Interaction techniques essentially involve data manipulation and thus place greater emphasis on input than output.Output is merely used to convey affordances and provide user feedback.The use of the term input technique further reinforces the central role of input.Conversely, techniques that mainly involve data exploration and thus place greater emphasis on output are called visualization techniques. They are studied in the field of information visualization.Information visualization is the interdisciplinary study of "the visual representation of large-scale collections of non-numerical information, such as files and lines of code in software systems, library and bibliographic databases, networks of relations on the internet, and so forth"
13Research and innovation A large part of research in human-computer interaction involves exploring easier-to-learn or more efficient interaction techniques for common computing tasks. This includes inventing new (post-WIMP) interaction techniques, possibly relying on methods from user interface design, and comparing them with existing techniques using methods from experimental psychology.Examples of scientific venues in these topics are the UIST and the CHI conferences. Other research focuses on the specification of interaction techniques, sometimes using formalisms such as Petri nets for the purposes of formal verification.