[XeTeX] Hyphenation questions

[Jonathan Kew]

On 26 Jun 2009, at 12:40, Vadim Radionov wrote:

> Hello,
>
> I have a couple of questions about hyphenation.
>
> First of all, am I wrong or XeTeX does not show possible hyphenation  
> points in output when typesetting with fonts other than default?   
> (I'm missing it.)

You are correct. This is because it does not retain the unused  
hyphenation points in the paragraph, because they would disrupt the  
application of OpenType features such as contextual forms, ligatures,  
or kerning.

I realize it can be helpful to see what hyphenations were considered,  
but currently the only way to find this out would be via the  
\tracingparagraphs output, I think -- which is hardly convenient for  
casual use!

For the same reason, the plain TeX \showhyphens macro will not work  
when xetex is using an opentype font. I think the xltxtra package  
provides a replacement macro, IIRC.

> Second.  Can I add hyphenation with \hyphenaton{so-me-th-ing} in  
> preamble, as in TeX?

Yes.

> Third (not hyphenation).  How does XeTeX determine the normal space,  
> shrink and stretch?

It uses the width of the space character in the font as the normal  
space (\fontdimen2) and then sets the stretch and shrink values  
(fontdimens 3 and 4) to 50% and 33% of this. You are free to adjust  
them after loading the font, if you wish to fine-tune the spacing/ 
justification behavior. (Note that the fontspec package includes  
support for this, if you're using xelatex.)

> And fourth. Is it OK to change the catcode of certain unicode symbol?

Yes.

JK