Representing Appearance Information in a World of
Interchangeable Documents
Ethan V. Munson
Abstract
Computer science currently lacks a widely applicable definition for
the concept of a medium. Most existing definitions are implicit
and treat data types, such as video streams, text, and digital audio,
as examples of media. This viewpoint does a poor job of
discriminating between many pairs of media, such as 2D static graphics
and 2D animation, which share the same set of data types.
Furthermore, this viewpoint is not suitable as a conceptual basis for
software services that can be configured to serve many different
media.
This paper presents presents a new, operational model of media. This model
asserts that a medium is a triple M = (T, D, O), where T is a set
of primitive data types (such as video streams or spline paths), D
is a set of dimensions in which layout is performed, and O is a set
of formatting operations with typed parameters. The model is
sufficiently rich to discriminate between all commonly used media and
can also be used to make statements about the extent of differences
between media.
The model also has a practical use. It is the conceptual basis for
Proteus, a software tool that manages the appearance and layout of
multimedia documents. This tool uses a description of a medium to
adapt its generic formatting services to that medium's needs.
Full text in PostScript.
This paper will appear in the Proceedings of the Third International
Workshop on Principles of Document Processing, Palo Alto, CA,
September 1996.