[XeTeX] \XeTeXuseglyphmetrics (was Re: Re: [OS X TeX] gtamacfonts ligatures: PDF searchability)

Bruno Voisin bvoisin at mac.com
Wed May 17 18:36:52 CEST 2006


Le 28 mars 06 à 18:36, Jonathan Kew a écrit :

> In the current development version of XeTeX, which will be released  
> as 0.991 when I get enough time to put a new package together,  
> there is a parameter \XeTeXuseglyphmetrics you can set that causes  
> the engine to use true glyph height and depth metrics in these  
> computations, instead of the font-wide ascent and descent. (This is  
> an optional setting, as there's a performance hit for using this,  
> and for simple running text it is often not needed.)

Having built version 0.991 recently, I was feeling adventurous today  
and decided to give the newly added glyph metrics setting a try.  
Searching through earlier messages I found the name  
\XeTeXuseglyphmetrics in the quoted message, and the syntax  
\XeTeXuseglyphmetrics=1 in the attachement xetex-sample2e.tex from a  
more recent message "Rép : [XeTeX] Correct LaTeX-logo – how?" from 7  
May.

Thus I tried putting \XeTeXuseglyphmetrics=1 in a XeLaTeX document,  
before \begin{document}. Without it, here's what I get for example:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 2.png
Type: image/png
Size: 11121 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0006.png 
-------------- next part --------------



-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 8.png
Type: image/png
Size: 22738 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0007.png 
-------------- next part --------------


And then with it:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 5.png
Type: image/png
Size: 10015 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0008.png 
-------------- next part --------------



-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 9.png
Type: image/png
Size: 22664 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0009.png 
-------------- next part --------------


In the first case, the parentheses (entered through \left( and  
\right)) are given a more appropriate size; in the second case, the  
extra interline spacing added by the presence of a superscript is  
made very very slightly smaller, but not much. The fonts are a  
mixture of Hoefler Text for text and Lucida for maths.

By contrast here's what I'm getting with Lucida only in pdfLaTeX:

-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 7.png
Type: image/png
Size: 9852 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0010.png 
-------------- next part --------------



-------------- next part --------------
A non-text attachment was scrubbed...
Name: Image 10.png
Type: image/png
Size: 22341 bytes
Desc: not available
Url : http://tug.org/pipermail/xetex/attachments/20060517/8ee769a9/attachment-0011.png 
-------------- next part --------------


In this case, the superscript does not create any extra interline  
space, and that's what I was hoping to reproduce in XeLaTeX.

Hence the question: what's the exact syntax of \XeTeXuseglyphmetrics?  
Is it boolean, with only two values 0 for false and 1 for true? Or is  
it like pdfTeX's \protcode, having several values 0, 1 and 2  
corresponding to the "intensity" with which the correction is applied?

I did not notice any significant performance hit when using  
\XeTeXuseglyphmetrics, by the way.

Bruno Voisin


More information about the XeTeX mailing list