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

[Bruno Voisin]

Le 18 mai 06 à 09:59, Bruno Voisin a écrit :

> I'm still missing the tightier and more regular spacing from the  
> third case, which seems essentially caused by the different  
> placement of the superscript "1/2" (a bit further on the right, and  
> further down, in pdfLaTeX). I've not managed to understand how the  
> metrics were created for the Hoefler Text font in the gtamacfonts  
> collection of packages; hence I've no idea on what could be done in  
> XeTeX about this, if anything can indeed be done.

Looking more closely, I'm having the impression this might be a XeTeX  
feature: XeTeX calculating the glyph metrics for the standard font  
size, and using it afterwards for all sizes without scaling it fully;  
or applying \lineskiplimit differently depending on the size; or the  
way font sizes and associated placement parameters are defined in  
LaTeX playing bad with XeTeX font model.

What has me thinking this: the earlier example was from a figure  
caption, typeset in \footnotesize; and looking more closely, I'm not  
seeing exactly the same effect in the body of the paper, in  
\normalsize. Namely, descenders on one line followed by superscripts  
on the next line add some interline spacing in \footnotesize:

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but not in \normalsize:

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In \normalsize I'm even seeing XeTeX accepting practically zero  
vertical space between a descender and a superscript:

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I'll stop here, as I'm really only guessing.

Bruno Voisin