Adult Web Design

Touch Means a Renaissance for Radial Menus

17.11.2013

In computer interface design, a pie menu (also known as a radial menu) is a circular context menu where selection depends on direction. A pie menu is made of several "pie slices" around an inactive center and works best with stylus input, and well with a mouse. Pie slices are drawn with a hole in the middle for an easy way to exit the menu.

Pie menus work well with keyboard acceleration, particularly four and eight item menus, on the cursor keys and the number pad. A goal of pie menus is to provide a smooth, reliable gestural style of interaction for novices and experts.

A slice can lead to another pie menu; selecting this may center the pointer in the new menu. A marking menu is a variant of the technique.

As a kind of context menu, pie menus are often context-sensitive, showing different options depending on what the pointer was pointing at when the menu was requested.

It makes good sense that itchy-trigger-finger games have adopted the radial menu over more typical list-based menus. In games, limiting interruptions is essential to the experience, and radial menus are more efficient than other selection tools. More interfaces should follow the gamers’ example here.

Radial menus are faster to access than list-based menus in every kind of pointer-based UI, including cursor, stylus, and touch. One big part of that is because every option is spaced at the same distance from the pointer. That’s classic Fitts’ Law: the closer the target and the bigger it is, the easier and faster it is to hit. (So you know: Fitts’ Law also explains why golf is such a miserable sport.)

Even better: you get faster with radial menus over time, because they take advantage of muscle memory in a way that list-based menus cannot. Radial menus are essentially gesture-based: touch-swipe-release. That’s why some call radial menus “marker menus”: it’s like making a mark on the screen. Swiping to 2 o’clock has one meaning, and swiping to 6 o’clock another. Like all physical actions—playing an instrument, typing a keyboard, serving a tennis ball—gestures get embedded in muscle memory, which is faster to access than visual memory. Tap-swipe is faster than scanning for an item in a linear list, just like touch-typing is faster than hunt-and-peck.

The research on this has been in the can for nearly 25 years. A 1988 study did the comparison and found that for a specific test of eight-item lists, users were faster with radial menus than linear ones. And it turns out that speed only improves.