VIEWING AND FORMATTING DOCUMENTS ON-LINE
Flexibility in document preparation systems is important in many ways. Typographical convention directs one to format information in different ways to account for different display hardware capabilities, intended purposes, user preferences and presentation style standards. The advent of interactive computer-mediated viewing of text suggests broadening the concept of "document" to include dynamic and static information from any source, including animated graphics, interactive program dialogues, optional linkages to other data sources and many other possibilities. Despite performance constraints which tend to favour the fastest, simplest display formats, rising user expectations and increased hardware and software capabilities encourage consideration of traditional typography in on-line documents. Flexibility is enhanced by separating specification of form from that of content; this can be achieved to a great degree through object-oriented data representation and programming. Efficiency and speed questions are raised by the prospect of interactive viewing with on-the-fly formatting. These questions are addressed by JOT, a prototype distributed document formatting and viewing system that is flexible and extensible. JOT is intended as a framework or testbed for investigating mechanisms for computer-mediated typography, not as an end-user application system itself. Its implementation, though imcomplete, is suggestive of the merits of this approach.