ABSTRACT
The family of idioms known as focus+context are based on the design choice to embed detailed information about a selected set—the focus—within a single view that also contains overview information about more of the data—the context. These idioms reduce the amount of data to show in the view through sophisticated combinations of filtering and aggregation. One design choice for embedding is to elide items, where some items are filtered out completely while others are summarized using dynamic aggregation for context; only the focus items are shown in detail. Another choice is to superimpose layers, where a local region of focus information can be moved against the background layer of contextual information. The goal of embedding focus and context together is to mitigate the potential for disorientation that comes with standard navigation techniques such as geometric zooming. Focus+context idioms attempt to support orientation by providing contextual information intended to act as recognizable landmarks, using external memory to reduce internal cognitive load.
