[ePiX-devel] Output formats

[Andrew D. Hwang]

The output format interface has been substantially re-written, but will 
not undergo additional large changes. (Even if I've overlooked something, 
only new functions will be added; the signatures of existing functions are 
all but set in stone.)

> From now on, an Output Format _must_ provide the following capabilities:

* Place a chunk of LaTeX code at a specified page location.
* Draw a line segment between arbitrary points.

In particular, the format base class handles all conversion of internal 
data structures to LaTeX code, and handles drawing of non-solid lines. 
This provides uniformity of appearance and simplicity of implementation, 
but does make non-solid lines relatively "expensive" in output file size.

Filled regions _can_ be implemented (imperfectly at present, and very 
inefficiently, as in eepic) using only line segments, but an output format 
(e.g. pst) is free to use its own filling capabilities.

For complete functionality and expected behavior, a format _should_

* Provide solid lines of arbitrary color and width.
* Build a scene serially, with later elements atop previous elements.


New output classes need only provide low-level operations (strings for 
starting or ending a picture or open/closed path, etc.) and a couple of 
high-level functions (how to print a filled region or a polyline with two 
pens). The skeleton files fmt_template.{cc,h} can be converted into source 
files for an output class with sed.


Andrew D. Hwang                 address@hidden
Department of Math and CS       http://mathcs.holycross.edu/~ahwang
College of the Holy Cross       (508) 793-2458 (Office: 320 Swords)
Worcester, MA, 01610-2395       (508) 793-3530 (fax)