[XeTeX] XeTeX and DejaVU Sans Mono Kerning in Adobe Reader

[Jonathan Kew]

On 15 Jul 2008, at 11:35 AM, Bernhard Fisseni wrote:

> Good morning,
>
> I am not sure whether this is a XeTeX bug, an Adobe Reader bug or a
> bug in the DejaVu Sans mono font, but maybe you can help me anyway.
> This problem only occurs if I use DejaVu Sans Mono with XeTeX/
> xdvipdfmx and view the resulting PDF with Adobe Reader.  (I have not
> found any corresponding bug reports, but maybe this is a known issue,
> as DejaVu seems to be a very usual font.)

It was not a known issue to me, at least, until now.

> I used XeLaTeX[1] with xdvipdfmx to produce presentation slides for a
> course.  As monospaced font I used DejaVu Sans Mono. Now, if I open
> the resulting document in Adobe Reader[2], it seems to apply kerning
> to the monospaced passages (see the slide at http://www.uni-due.de/~hg0132/XeTeX-DejaVu.pdf
> , look at the dashes and "|"s; see also the attached rather minimal
> example, look at the "T.T," and the "|", but also the "wi").

Yes, I see the problems you're describing, with Reader versions 5, 8  
and 9 (but not with any of the non-Adobe viewers).


> PDF should be rather viewer independent.

In theory, it should be. Unfortunately, theory and practice don't  
always match!

It's not clear to me whose bug this is. It seems that the particular  
way this font is built and embedded in the PDF by xdvipdfmx leads to  
an inconsistency in how the viewers treat it, with Reader disagreeing  
with the other products (PDFkit, poppler, etc). But it will take some  
serious dissection of the file to understand what is going on, and  
whether the real fault is in the font (probably not), the PDF  
generation process (quite possible), or the viewer application (also  
possible).

If any PDF experts wish to look into this, please do! I don't have  
time to investigate it thoroughly at the moment, but there's  
definitely an issue that needs to be understood and resolved somehow.

JK