Zoomin' Ahead

A zooming user interface could provide a whole new way to navigate through desktop directories - no more clicking through level after level of hierarchical data directories or scrolling through elusive pull-down menus. Your mouse will soon rocket you around your desktop.

Graphical user interfaces (GUI) look slicker than ever, but users are still getting repetitive stress syndrome and eyestrain from clicking on tiny icons and arrows to delve through level after level of hierarchical menus or snatch at skittish pop-out menus.

"I hate that," says Benjamin B. Bederson, director of the Human Computer Interaction Laboratory (HCIL) at the University of Maryland in College Park. "And scrolling? Nobody likes scrolling."

Bederson has been working on an alternative - zooming user interfaces (ZUI) - since the early 1990s.

A conventional GUI presents icons and text in a hierarchical list format. To see a list of the contents in Subfolder A, you must first click on Folder A. Drill down three or four levels, and the initial lists are off the screen. To view Subfolder B, you must close folders and backtrack. Total clicks: 10.

With ZUIs, subfolders need not be buried from view. The entire folder structure, in miniature, is on-screen. As a mouse pointer rolls over a folder or subfolder, that part of the structure leaps to the fore in conventional-size type while the rest of the miniaturized file structure remains on-screen. To drill down three or four levels, move the mouse an inch or so. To get to Subfolder B, make another 1-inch mouse move. Total clicks: none.

"ZUIs are at their best when interacting with hierarchical data," Bederson says, because "they eliminate window management problems and offer a way of navigating through information intuitively."

For example, network management software is a good target for a ZUI, he says. "Networks are hierarchical, have more information than fits on the screen, are visual and require understanding of overview and detail," Bederson adds.

Exploring the Possibilities

The ZUI's potential for improving business software is virtually untapped, according to Juan-Pablo Hourcade, a graduate student on Bederson's research team.

"One scenario we've been exploring is in presentations," Hourcade says. "Everyone uses PowerPoint, so another graduate student, Lance Good, is developing CounterPoint as a PowerPoint plug-in."

Users create their slides in Microsoft PowerPoint and "then just click to bring them into the zooming space," Hourcade says. All the slides are on the screen at once; a user rolls the mouse to zoom in to one slide and rolls back for the overview.

"It means your presentation is no longer linear - you can choose which slides to show and in what order," he says. "You don't have to create new presentations for each audience. Whenever we give a presentation using zooming, it gets a big response."

Bederson's team has also developed KidPad, a storytelling application for children that illustrates ZUI functionality.

A user begins a drawing and then uses the middle button of a three-button mouse to zoom in. He adds details or text on a new layer at the new scale, zooming and repeating for further layers and clicking to back out and view the composite image. A story can include dozens of such images and allows a viewer to zoom from one image or layer to another and back.

CounterPoint and KidPad were built on Jazz, Bederson's free Java software development tool kit, which is set for a July 4 release.

Bederson used C++ to build Pad++, Jazz's predecessor, with Jim Hollan, now a professor at the University of California at San Diego. Pad++ "was aimed more at prototyping than real applications," Bederson says. The open-source Jazz was "structured for good software engineering and larger systems building," he adds.

Ken Perlin, a professor at New York University, is credited with coming up with the original idea for ZUIs. "Zooming isn't new," Hourcade says. "But what hasn't been around is a tool kit that lets you easily do it for any application."

Jazz also features fish-eye menus. In a fish-eye menu view, all items in a list are at least nominally visible.

Bederson and George W. Furnas first developed fish-eye views at Bell Communications Research in College Park, Md., Hourcade says, "but nobody had thought of fish-eye menus" until Bederson dreamed up the idea.

"Not exactly in a dream," Bederson says, "but I did wake up at 6 a.m. one Saturday with the idea clearly in my head. I hadn't even been considering the idea earlier." He spent the rest of the day writing the first version of the code.

Each item in a 100-item list on an average screen would be in type about 4 pixels high, Bederson says. As the mouse pointer moves over a list, the dozen or so list entries centered under the pointer gradually grow to normal viewing size.

Studies at the HCIL have shown that users prefer fish-eye menus for browsing and are about equally divided between fish-eye and hierarchical menus for more goal-directed tasks.

Copyright © 2000 IDG Communications, Inc.

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