|On the Syntax of Diagrams *
Fred Lakin, the paul graphic charlie company
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
- A text-graphic object is either a line or a pattern:
A line is a either a drawline or a textline
- A drawline is either a colored stroke drawn through one or more locations,
or a (not necessarily rectangular) group of colored dots:
- A textline is one or more characters (a character is a pattern of one or more drawlines)
- A pattern is a group of one or more text-graphic objects
Details and Examples
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.
Romanji text: example syntax showing how Roman
can be defined as 26 little patterns with certain conventions
for arranging them spatially.
Diagrams, visual languages, and spatial parsing: some definitions.
Binary Trees: example syntax; and machine
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 Romanji text
* Originally written for
Alan Blackwell's THINKING WITH DIAGRAMS '97 WORKSHOP,
Portsmouth, England, January 9-10, 1997; subsequently modified
after reading Yuri Engelhardt's thesis July 25, 2002.
A one Web page summary of this article appeared at Alan's site,
and a paper version was printed in the proceedings.
© 1996, 2002 PGC