[XeTeX] weird behaviour with LetterSpace

[Pablo Rodríguez]

On 06/01/2010 09:47 PM, Jonathan Kew wrote:
> On 1 Jun 2010, at 20:00, Pablo Rodríguez wrote:
>
>> I'm not especially interested in LetterSpace, but in hyphenation with Letterspace (as you can see at http://www.ousia.tk/grammatike.pdf).
>
> I can't think of any reason why LetterSpace should prevent hyphenation. Are you sure it's not just that there isn't enough flexibility in the line for TeX to find "acceptable" breaks, and so it leaves an overfull box? You could try LaTeX's \sloppy declaration to allow looser spacing; and if this proves helpful, you could look into fontspec's word-spacing controls. Making the word spaces more stretchable in the letterspaced text might be what you need in order for line-breaking and hyphenation to have a better chance of success.

\sloppy didn't make any difference. Just in case I'm missing something, 
the source file can be found at http://www.ousia.tk/grammatike.tex 
(Theano Didot is a freely available font).

As I wrote in my previous message to the list, I discovered that 
letterspacing in TeX is problematic 
(http://www.tug.org/TUGboat/Articles/tb29-1/tb91thanh-fonts.pdf).

pdfTeX seems to be the only engine capable of handling tracking or 
letter space properly (according to its developer). LuaTeX hasn't 
implemented this yet. The microtype package provides an interface for 
using letter space with pdfTeX.

I wonder whether the primitives described by Than could be implemented 
in XeTeX. And whether font expansion would be included in XeTeX also.

Thanks for your help,


Pablo