Re: more on missing ligatures

[Hans Hagen <pragma@wxs.nl>]

At 02:38 PM 3/9/2002 -0600, Bill McClain wrote:
>Bill McClain wrote:
> >
> > I'm back to investigating why Context is not displaying ligatures from
> > my new Adobe Sabon font. I've discovered something else which may be a
> > clue: Context and plain pdftex differ in the glyphs they generate from
> > the same font file. I presume this is caused by some improper definition
> > at my end, but I don't know how to diagnose it.
>
>More info: the map file which texfont produces references the newly
>created tfm files. However, it looks to me as if there is no ligature
>information in those files. The virtual font files do have ligature
>info, and when I change my font declarations to use the vf files (for
>example, "texnansi-sar" instead of "texnansi-raw-sar"), then Context
>produces the ligatures properly.
>
>I'm not sure how that can be, because "texnansi-sar" is not even listed
>in the map file.
>
>Is there some automatic linkage between the tfm and vf files which I am
>missing? Or should the map file reference the vf files directly?

If you use virtual fonts, as far as i know, tex itself uses the font:

   somefont.tfm

which is accompanied by a virtual companion

   somefont.vf

which can construct glyphs from multiple font files, in our case at least 
it uses the raw file, which is

   somefont-raw.tfm

Now, tex itself only needs the tfm file but dvips and the pdftex backend 
need the vf file in order to construct composed or manipulated glyphs. So, 
when vf was introduced, tex was not adapted, but dvips was,

I must admit that this model is not that clear -)

Hans

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