| Abstract | This paper discusses the design and implementation of interactivesmooth zooming of a starfield display. A starfield display is a two
dimensional scatterplot of a multidimensional database where every item
from the database is represented as a small colored glyph whose position
is determined by its ranking along ordinal attributes of the items laid out
on the axes. One way of navigating this visual information is by using a
zooming tool to incrementally zoom in on the items by varying the
attribute range on either axis independently - such zooming causes the
glyphs to move continuously and to grow or shrink.
To get a feeling of flying through the data, users should be able to
track the motion of each glyph without getting distracted by flicker or
large jumps - conditions that necessitate high display refresh rates and
closely spaced glyphs on successive frames. Although the use of
high-speed hardware can achieve the required visual effect for small
databases, the twin software bottlenecks of rapidly accessing display
items and constructing a new display image fundamentally retard the
refresh rate. Our work explores several methods to overcome these
bottlenecks, presents a taxonomy of various zooming methods and
introduces a new widget, the zoom bar, that facilitates zooming.
(Also cross-referenced as CAR-TR-714)
(Also cross-referenced as ISR-TR-94-46)
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