[XeTeX] XeTeX 1.0 - request for comments

[Jonathan Kew]

On 20 Oct 2005, at 6:46 pm, Florian Grammel wrote:
>
> I have now built several custom tec-files (one for just two f- 
> ligatures, one for all of them, &c.) and the results are just what  
> I had hoped for - great!
> Thanks for this hint!
>
> I'd guess that this replacement is made before the actual  
> typesetting, isn't it? Would my ligature-conversions affect babel's  
> hyphenation then?

No. Font mappings are applied at the very last moment, when XeTeX is  
drawing a string of text (or measuring it to make layout decisions),  
just as if the mapping were actually built in to the font. As far as  
the TeX engine is concerned, it doesn't "see" the replacement at all;  
it just deals with the original characters.

(Note, by the way, that this means you can't use a font mapping to  
introduce TeX macros, etc., into the text, or to match and change  
markup characters. The only text that passes through the font mapping  
is the actual character sequence that's going to be rendered, after  
all macro processing is over.)

So hyphenation patterns will still apply, regardless of the font  
mapping you use (although of course if the mapping causes the metrics  
of the words to change, TeX may end up making different line-break  
choices).

Hope this helps clarify things.

JK