Summary of Pie Menus at Usenix Work In Progress Session - June 1987

Directional Selection is Easy as Pie Menus!

Don Hopkins
University of Maryland
Heterogeneous Systems Laboratory
College Park, MD 20742
Written August 1987

Simple Simon popped a Pie Men-
u upon the screen;
With directional selection,
all is peachy keen!

The choices of a Pie Menu are positioned in a circle around the cursor, instead of in a linear row or column. The choice regions are shaped like the slices of a pie. The cursor begins in the center of the menu, in an inactive region that makes no selection. The target areas are all adjacent to the cursor, but in a different directions.

Cursor direction defines the choice. The distance from the menu center to the cursor, because it's independent of the direction, may serve to modify the choice. The further away from the Pie Menu center the cursor is, the more precise the control of the selection is, as the Pie slice widens with distance.

With familiar menus, choices can be made without even seeing the menu, because it's the direction, not the distance, that's important. "Mousing ahead" with Pie Menus is very easy and reliable. Experienced users can make selections quickly enough that it is not actually necessary to display the menu on the screen, if the mouse clicks that would determine the selection are already in the input queue.

The circular arrangement of Pie Menu items is quite appropriate for certain tasks, such as inputing hours, minutes, seconds, angles, and directions. Choices may be placed in intuitive, mnemonic directions, with opposite choices across from each other, orthogonal pairs at right angles, and other appropriate arrangements.

Pie menus have been implemented for uwm, a window manager for X-Windows version 10, for the SunView window system, and for NeWS, Sun's extensible PostScript window system. Don Hopkins did the uwm and NeWS implementations, and Mark Weiser did the SunView implementation.

Jack Callahan has shown Pie Menus to be faster and more reliable than linear menus, in a controlled experiment using subjects with little or no mouse experience. Three types of eight-item menu task groupings were used: Pie tasks (North, NE, East, etc...), linear tasks (First, Second, Third, etc...), and unclassified tasks (Center, Bold, Italic, etc...). Subjects were presented menus in both linear and Pie formats, and told to make a certain selection from each. They were able to make selections 15% faster, with fewer errors, for all three task groupings, using Pie Menus. Ben Shneiderman gave advice on the design of the experiment, and Don Hopkins implemented it in Forth and C, on top of the X-Windows uwm.

Date: Thu, 11 Jun 87 13:02:47 EDT
From: Don Hopkins <don@brillig.umd.edu>
To: weiser.pa@xerox.com, pete@brillig.umd.edu
Cc: don@brillig.umd.edu
Subject: USENIX

I am here, typing on John Gilmore's sexy little Kaypro. I gave a talk on Pie Menus. They had Work in Progress sessions, and I had a bunch of transparencies prepared. It went over very well. I brought some tapes, and loaded my NeWS stuff onto the machines at the Sun booth, and they were quite pleased to have the things to demo. I will be posting the source to NeWS Pie Menus soon, on the public domain, with no restrictions on distribution, so if the Technology Liaison Officer is trying to get in touch with me, you can tell him to get stuffed.

-Don