Pad A Zooming Graphical Interface for Exploring Alternate

Pad++: A Zooming Graphical Interface for Exploring Alternate Interface Physics Presented By: Daniel Loewus-Deitch

Introduction • Pad++ is a zooming graphical interface. • Possible alternative to traditional windows/icon interface design. • A different direction than many other groups exploring 3 D virtual worlds.

Metaphor vs. Physics • Metaphor-based approaches have certain limitations – Too much focus on old media. – Underutilizing potential of mechanisms associated with new computerized media. • Physics approach views interface design differently – Appearance and behavior of informational objects.

Metaphor vs. Physics • Examples of informational physics: – Useful representations to show extent of use for an object (i. e. dog-eared pages in real world). – History-enriched digital objects. – New physics for interacting with graphical data (i. e. zooming).

Metaphor vs. Physics • 4 problems with metaphor-based model: – Metaphors always pre-exist their use. • Metaphor must be familiar. • Limits resources and choices.

Metaphor vs. Physics – Metaphors are temporary bridging concepts. • Eventually they die as a metaphor and take on a common meaning in the computer environment. • After metaphor dies, it can still restrict functionality when trying to keep the metaphor from being violated. – Metaphor-based interface is not easily scalable. – Metaphors may lead users to expect functionality associated with the source object that is not actually included in the interface.

Metaphor vs. Physics • Issues with physics-based model – Can’t rely on user familiarity to same extent (learnability consequences). – Make sure physics mechanisms are easily discoverable and learnable.

Motivation • Desktop metaphor has hit a dead end. • Present large amounts of information with the same rich structure and dynamic character of the real world. • Create physics that symbolically relate to informational objects and exploit semantic relationships. • Attempting to fully utilize our natural spatial abilities.

Motivation • Pad++ provides more choices than just the inclusion or exclusion of information. • Make it easier to find specific information in large dataspaces. • Complements traditional filtering and recommendation approaches. – Highly rated information is largest. – Lower rated information is smaller and off to the side.

Pad++ System • General purpose • Supports these standard objects: – Colored text – Text files – Hypertext – Graphics – Images • Zooms around current cursor position.

Pad++ System • Originally designed for use with a 3 -button mouse. • Semantic zooming – When zoomed out, object is represented differently. It is not just scaled down.

Recent Advances • Focus on smooth zooming with large graphical datasets. • Essential that frame rates be consistently maintained because of nature of interaction. • Coded in C++

Efficiency • New efficiency methods: – Spatial indexing – Restructuring – Spatial level-of-detail – Clipping – Refinement – Adaptive render scheduling • Search for balance between local detail and global context.

Efficiency • Parallel lazy loading – Helps avoid start-up costs of parsing and loading database when accessing external information sources. – Only loads portion of database that is currently visible. – Performed in background. • Ephemeral objects – Automatically deleted if not viewed within several minutes.

Hypertext • Multiscale layouts – Graphically represent parent-child relationship between links. – Linked data is loaded to side and made smaller. Then view is animated to center new data.

Interface to TCL/TK • 3 classes: – Create objects – Handle objects – Render scene • Every object assigned a unique integer id. • Procedural objects support semantic zooming.

Interface to TCL/TK • Navigation and search mechanisms provided. • Most of panning is performed while zoomed out. – Gives sense of context. – Speeds up animation.

Visualizations • Pad++ directory browser – For viewing large hierarchical databases. – Square frame = directory – Solid square = file – Text names shown when zoomed in. – Search by zooming in and out of directory tree or by content-based search. – Zooming into file loads text inside colored square.

Visualizations • Timeline – Helpful to look at history using different scales. – Zoom into particular years to see content in detail.