On the Syntax of Diagrams

On the Syntax of Diagrams

Fred Lakin, The Performing Graphics Company
lakin@pgc.com

I find it useful to defer making the syntactic distinction between text and graphics for as long as possible. So I ambiguously refer to a discernible visual chunk like a diagram as a "text graphic object", which may in turn recursively be a pattern of other text graphic objects. At the bottom finally are visual "drawlines".

A text-graphic object is either a drawline or a pattern:

A drawline is either a colored stroke drawn through
one or more locations, or an array of colored dots:
A pattern is a group of none or more drawlines and/or patterns:

Details and Examples

Text graphic object notation: how the spider webs work, various relations of spatial structure to tree structure.

And, no, text graphic object notation is not the syntax for diagrams, but rather a notation for describing various possible syntaxes ... at the bottom is an operational definition of structure in text graphic images.

Romaji/Romanji text: example syntax showing how Roman style text can be defined as 26 little patterns with certain conventions for arranging them spatially.

A more detailed version of this page, with Kanji pictograph examples, was generated in July 2002 for Yuri Engelhardt.

Diagrams, visual languages, and spatial parsing: some definitions.

Binary Trees: example syntax; and machine readable, visually notated context free grammar used by a spatial parser to recover underlying syntactic structure.

Bar charts: example syntax; visual grammar.

Blackboard Image with embedded diagrams: example syntax only (grammar and parsing part of on going work ...)

Textual BNF: character only syntax for text graphic objects and Romaji text.

References

A one Web page summary of this article appears at the site of the THINKING WITH DIAGRAMS '97 WORKSHOP, Portsmouth, England, January 9-10, 1997; and a paper version was printed in the proceedings.