Count (and limit) glyphs per line?

[Benjamin Buchmuller via ntg-context <ntg-context@ntg.nl>]

Dear list,

I've been confronted with the following 'intriguing' formatting requirement for a document:

"
• Type density:  Must be no more than 15 characters per linear inch (including characters and spaces).
• Line spacing: Must be no more than six lines per vertical inch.
"

While the line spacing resolves in ConTeXt to

\setupinterlinespace[line=\dimexpr(1in / 6)]

I was wondering if one can limit "type density" as the number of glyphs per inch in TeX too? I thought, it is more convenient to rephrase this request (for a 7 in textwidth) to limit the number of glyphs per line to 112. (Font must be sans or serif, of course ...)

I've tried

\setuplayout[width=112\averagecharwidth] 

which, however, results in ~120–130 characters and spaces per line. Pragmatically, I'm narrowing the text width to empirically match the requirement, but I'm nevertheless curious if there is a Lua/TeX solution to this "problem"?

Thank you!


Benjamin 
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________