[XeTeX] Embarrassing fontspec

[Jonathan Kew]

On 4 Jan 2006, at 5:57 am, Will Robertson wrote:

> Hello,
>
> In trying to complete fontspec 1.9 before the new year properly  
> begins, I've come across a very strange problem that has me totally  
> stumped.
>
> The fontspec documentation contains lots and lots of examples, and  
> I noticed that after a certain number of them, the default roman  
> text went all funny. In order to determine that it was indeed  
> fontspec's fault and no other, I assembled a test file that  
> contained only the examples from fontspec.dtx, typeset directly,  
> with some counting text in-between. Look what happens:
>
> <texshop_image.png>
>
> The "test words 50" text seems to take up no space (the \fbox is  
> just a single line) and the characters are truncated after the  
> first four, and are obviously in the wrong spots.
>
> A similar test with plain XeTeX commands yielded fine results, so  
> somewhere in fontspec, I've made a terrible error. But what on  
> earth could it be? Am I using up some of XeTeX's mojo, and it  
> eventually forgets how to place characters on the page properly?

But surely XeTeX has unlimited mojo? ;-)

No, seriously, I suspect you may have encountered a XeTeX bug.  
Remember that using fontspec rather than simple \font commands makes  
XeTeX work a lot harder--all that extra macro expansion, looking for  
the various fonts that make up a family, etc. So you're stressing it  
more, and running into a bug that doesn't show up under more  
"typical" conditions.

I'll try to look into it--I was able to reproduce the problem, or  
something very similar--I had to substitute a few fonts where I  
didn't have the ones you're using, but I can confirm that it's not  
just your system. And my guess is it's a XeTeX bug rather than a  
fontspec one, but more investigation is needed to pin it down.

JK