User Interface Demonstration for CHI '88

		     How to Choose with Pie Menus

Demonstration Description

	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.

	The demonstration will show pie menus implemented in
	PostScript, running under the NeWS window system. It will
	include:

	    pie menu selection with mouse,
	    canceling a menu without making a selection,
	    browsing around a nested menu hierarchy,
	    mouse ahead and menu display suppression,
	    "pull down" versus "pull round" menus,
	    iconic and graphical menu labels,
	    menus with interactive animated feedback,
	    two dimensional menus using direction and distance (font/size),
	    scrolling pies (directional valuators),
	    precision pie dials (high accuracy valuators),
	    and an efficient mouse tracking algorithm.

Demonstrators

	Don Hopkins
	don@brillig.umd.edu
	University of Maryland
	Human Computer Interaction Lab
	5819 Ruatan St.
	College Park, MD 20740
	(301) 474-8027, (301) 454-1517

	Jack Callahan
	callahan@brillig.umd.edu
	University of Maryland
	Computer Science Department
	College Park, MD 20742
	(301) 454-1517