DOCBOOK-APPS: representing and rendering symbol characters

[Erik Hennum <erik dot hennum at informix dot com>]

Honored DocBooklians:

We're converting styled FrameMaker text to XML DocBook.

A particular worry is how to handle the symbol characters from 
the symbol and dingbat fonts (and from the extended character
set).  The documents sometimes use a symbol as an 
embedded image rather than for its conventional meaning.

Most of the character set from the symbol font could be mapped 
to ISO character entities.  However, rendering the entity seems 
problematic.  

The HTML XSLT scripts pass through the ISO entities in the 
generated HTML.  The mainstream browsers seem to have 
only limited support for the ISO entities.

We could redefine the ISO entities as HTML image tags.  (Are 
the glyph bitmaps from the DocBook guide okay to reuse?)  This 
approach, however, would prevent changing the symbol size
through the font size.

Does the symbol font have a consistent character set across 
platforms?  If so, we could redefine the ISO entities as HTML 
font tags applying the symbol font to the appropriate characters.  

At that point, it becomes tempting to skip the middleman 
and store the font association in the XML file, rationalizing it 
as a way to specify the symbol.

This approach would also handle characters (particularly 
dingbats) that don't have equivalent ISO entities.

What would be the best way to delimit the symbol characters 
in the XML?  Using an emphasis or phrase element with 
a role attribute?  

For instance, to represent the arrowright symbol via 
the \xae hex character in the symbol set:

    <emphasis role="symbolset">\xae</emphasis>

Or is there some better way to handle this?


Thanks in advance for any clarifications or suggestions,


Erik Hennum
erik.hennum@informix.com