Pie menu

File:Piemenu.jpg

Example for a pie menu taken from the computer game The Sims. The player can choose the options by moving his mouse away from the center into one slice of the "pie".

A pie menu (also referred to as a "radial menu") is a user interface which is designed for quick selection of a limited number of options in a computer application, usually with a mouse. A typical pie menu requires the user to click a mouse button, after which the pie menu "pops up". Often the pie menu will be context sensitive, depending on what the mouse cursor was pointing at before the pie menu was requested. Several "pie slices" are displayed around the center, each with an individual label (e.g. "Open", "Close" at the top and bottom, "Next", "Previous" at the left and right). The user then moves the mouse, often while still holding the mouse button, into the desired slice. After doing so, he either has to release the mouse button, or select the respective option by clicking it. Some of the options may lead to further pie menus; this may automatically move the mouse cursor back to the middle of the pie menu. Cancelling a layered pie menu is possible by clicking in the centre of the menu.

Pie menus were invented by Don Hopkins. They are often used in games (examples: The Sims, Monkey Island 3, Full Throttle, Neverwinter Nights) because they only require screen space when activated. As opposed to conventional linear context menus, they allow very fast access to commonly used actions, as the experienced user is often able to pre-empt the position of the action that they wish to select, and the area within which they have to click is often larger. This is similar to the way mouse gestures work, but differs in that the user does not have to consult a manual, rely on trial and error or go through tedious training before being able to use the gestures. For applications which are used regularly, mouse gestures may be preferable because of their lower intrusiveness. Optionally, pie menus may be designed in such a fashion that they only pop up when the mouse button has been held down for a certain amount of time, so they operate like mouse gestures when used quickly.

References

• Jack Callahan, Don Hopkins, Mark Weiser, Ben Shneiderman (1988). An empirical comparison of pie vs. linear menus. Proceedings of ACM CHI Conference on Human Factors in Computing Systems, 1988, pp. 95--100. http://doi.acm.org/10.1145/57167.57182

• Don Hopkins (1991). The Design and Implementation of PieMenus. Dr. Dobb's Journal, 1991, volume 16, number 12, pp. 16--26.