Direct manipulation interface

In computer science, direct manipulation is a human–computer interaction style which involves continuous representation of objects of interest and rapid, reversible, and incremental actions and feedback. As opposed to other interaction styles, for example, a command language, the intention of direct manipulation is to allow a user to manipulate objects presented to them, using actions that correspond at least loosely to manipulation of physical objects. An example of direct-manipulation is resizing a graphical shape, such as a rectangle, by dragging its corners or edges with a mouse.

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, thus evaluating the output and compensating for mistakes.

The term was introduced by Ben Shneiderman in 1982 within the context of office applications and the desktop metaphor. Individuals in academia and computer scientists doing research on future user interfaces often put as much or even more stress on tactile control and feedback, or sonic control and feedback than on the visual feedback given by most GUIs. As a result, the term has been more widespread in these environments.

Direct manipulation is closely associated with interfaces that use windows, icons, menus, and a pointing device (WIMP GUI) as these almost always incorporate direct manipulation to at least some degree. However, direct manipulation should not be confused with these other terms, as it does not imply the use of windows or even graphical output. For example, direct manipulation concepts can be applied to interfaces for blind or vision-impaired users, using a combination of tactile and sonic devices and software.

Compromises to the degree to which an interface implements direct manipulation are frequently seen. For example, most versions of windowing interfaces allow users to reposition a window by dragging it with the mouse. In early systems, redrawing the window while dragging was not feasible due to computational limitations. Instead, a rectangular outline of the window was drawn while dragging. The complete window contents were redrawn once the user released the mouse button.

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