[XeTeX] Strangeness with Minion Pro Opticals Small Caps

[Peter Heslin]

Jonathan Kew <jonathan_kew at sil.org> writes:

> If you're in the mood to experiment, perhaps you could (temporarily)  
> reinstall the Reader-provided fonts and remove the Type Classics  
> versions. I think the problem will return.

You are right, as usual.  With only the Reader-provided fonts installed,
the problem returns (for both sizes of text, of course).  The reason I
had ruled out a bug in those fonts as a possible explanation is that I
assumed I would have come across this problem in my earlier usage (and
now that I think harder on it, I have a vague memory that maybe I did
when I was first testing xetex).

> If I'm right, it's not an "incompatible font situation", it's a badly- 
> programmed GSUB table -- which xetex can't realistically detect, as  
> it can't know what the font designer intended. It just follows the  
> rules.

Definitely.  I'm just surprised that such a widely-distributed font
version has such a major error.

> I suppose it might be possible, and sometimes helpful, to detect when  
> there are multiple versions of a font installed, as this means you're  
> unable to control which of the versions will be used, and may  
> inadvertently be using an old font that you thought you'd replaced.  
> I'd need to give a bit of thought to how/where this could best be  
> detected.

Maybe it would be best if running fc-cache would give a warning of this
sort.  That way the user would be alerted to the problem at the point
when she installs the conflicting font, and other applications would
benefit from the fix.

-- 
Peter Heslin (http://www.dur.ac.uk/p.j.heslin)