[XeTeX] optical sizes not found

[Khaled Hosny]

On Tue, Oct 05, 2010 at 10:51:21PM +0200, Roland Kuhn wrote:
>  Am 05.10.2010 22:41, schrieb Khaled Hosny:
> >On Tue, Oct 05, 2010 at 10:32:51PM +0200, Roland Kuhn wrote:
> >>  Hi,
> >>
> >>a few days back I asked about a problem with optical font sizes: for
> >>me, the correct fonts are not automatically selected. I can rule out
> >>a fontspec bug, since the problem exists also in plain XeTeX:
> >>
> >>\font\1="Kepler Std" at 9pt\1
> >>Hallo Welt!
> >>\font\2="Kepler Std" at 12pt\2
> >>Hallo Welt!
> >>\font\3="Kepler Std" at 14pt\3
> >>Hallo Welt!
> >>\font\4="Kepler Std" at 24pt\4
> >>Hallo Welt!
> >>\end
> >>
> >>This results in a PDF containing only the KeplerStd-Regular font (no
> >>Capt, Subh or Disp variants). Now I've had the opportunity to test
> >>this using the same OTF files on a Windows 7 computer with an
> >>up-to-date TL2010 installation, and the same happens as on my Mac
> >>(Snow Leopard, same TL2010 revision).
> >>
> >>Could it be that the fonts do not contain some needed hints? (I'm
> >>using the version from 2003.) How does font selection work on the
> >>inside?
> >The font need to have a "size" feature for automatic optical size
> >selection to work, you can check with otfinfo (part of texlive) if the
> >font have such feature. If not, then fontspec has options for manually
> >selecting optical sizes.
> >
> >Regards,
> >  Khaled
> >
> Yes, I was aware of the feature, and here is the output of "otfinfo
> -z" on my regular ("Text") variant:
> 
> design size 11 pt, size range (8.9 pt, 13.9 pt], subfamily ID 4,
> subfamily name Regular
> 
> I wonder where XeTeX should now take the information to look for a
> font named KeplerStd-Capt.otf or "Kepler Std Capt" when I select it
> at 8pt? (forget my 9pt in the example above, I've just verified that
> using 8pt does not make a difference)

I'm not sure if I understand what you are asking for, but you can
explicitly ask for a specific optical size, e.g.:

  \font\1="Kepler Std/S=8" at 8pt\1
  Hallo Welt!

And see if that works (you can also try with lualatex, if both fail
then it is likely to be a font issue).

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer