[XeTeX] Using Gentium with XeteX

[Jonathan Kew]

On 27 Oct 2007, at 10:31 am, Till Rettig wrote:

> I started using Gentium a while ago with XeteX, but realized, that  
> there
> is a caveat I cannot solve: The font comes only in two faces:  
> normal and
> italic. How do I achive bold face?

 From <http://scripts.sil.org/Gentium_status>:

"The Gentium project is not complete, but does provide a lot of  
functionality even in its current form.

First of all, the current version of Gentium only includes a single  
weight in regular and italic styles. High priorities are to provide a  
strongly contrasting bold weight...."

> In openoffice or ms word this is no
> problem, the program obviously has some font information that lets it
> scale the fonts accordingly.

Word processing programs, like Word or OpenOffice, will often apply a  
synthetic emboldening effect to fonts where no actual bold weight is  
available, but the results -- basically, a slight "smearing" of the  
glyphs -- are not of the same quality as a properly-designed bold  
face. (Similarly, slanting the regular face is a poor substitute for  
a real italic face, but these programs will do that too if you don't  
have the Italic face installed.) I think you'll find that higher-end  
publishing programs are less likely to provide such a function at all.

> Is there any option in the fontspec package
> that let you do the same?

No.

> I guess the idea behind this is, that italic
> face has different shapes while the bold version is only a scaled
> version of the normal or italic face where all lines are scaled
> accordingly. It seems the font designer thought this method is good
> enough to get sufficient results.

No, the font designer most definitely does not think this. The  
project isn't finished; it's a work-in-progress. There will be  
separate bold and bold-italic faces (actually, I believe there will  
be multiple weights, not just two). I don't know when a more complete  
package will be available, but hope it will be fairly soon; I know  
the designer has made a lot of progress on this stuff recently.

> But how do I tell XeteX to do the same?

You can't. Well, OK, if you really want to simulate such an effect  
with TeX, look up "poor man's bold" in The TeXbook, appendix D (p. 
386). But I wouldn't advise making much use of it. If you need  
extensive use of bold, that's a reason *not* to choose Gentium just  
yet, until a true bold face is available.

(If you're using Gentium because of the extensive Unicode repertoire  
it supports, as much as for its attractive design, you could consider  
trying Charis SIL <http://scripts.sil.org/CharisSILfont> in the  
meantime. This comes in the "standard" set of 4 faces already, and  
also has a very rich character repertoire.)

JK