fontinst with 8y.etx

Ulrik Vieth
Fri, 12 Jun 1998 11:31:46 +0200

Hilmar Schlegel wrote:

>> > BTW, if LY1 is functionnally equivalent to 8r, why 8r ?
>> Good question.  Personally, I find 8y (or LY1) slightly less arbitrary
>> then 8r.  Both provide access to all the glyphs available in standard
>> PostScript fonts, they just use a slightly different arrangement.

> No, there is a an essential difference: LY claims to be Acrobat-Reader
> proof when making PDF. If that works in any case, esp. on a Mac is not
> perfectly sure but it circumvents the most obvious traps.
> On the other side it is promoted with the argument to avoid the need of
> VF - which is only important for Dvi-interpreters not capable of doing
> VF and not relevant in the context of fontinst. 

I don't bother much about this because I have no problems with VF.  
I just was saying that if you build virtual T1 and OT1 on top of 8y,
you can you have all in one run, and you can use whatever you prefer.

>> Since hardly anybody seems to be interested in typesetting directly
>> with 8r, while OTOH Y&Y does promote typesetting with 8y (regardless
>> whether or not you may find that adequate for non-expertized fonts),

> Well, there is the difficulty that fontinst generated LY encoded TFMs
> are quite different from those made by the Y&Y tools. This leads under
> certain circumstances to a big processing overhead due to the fact that
> fontinst is rounding metric data to a grid of 1 AFM unit while the Y&Y
> tools do not round metric data. Also due to different checksums it is
> not straight forward to mix "raw" fonts from Y&Y and VFs made by
> fontinst.

I realize that rounding is indeed the problem, but there's little you
can do about it.  OTOH, my 8y.etx does put in a little more than just
straight converting and reencoding of the AFM metrics.  For instance,
I can easily put in all the TeX input ligatures, which you find in 8r,
such as `` and '' for quotedblleft and quotedblright, etc.

>> using fontinst to install 7t/8t/8c on top of 8y (and 8x, if available)
>> might turn out a compromise that could make eveyone happy?  WDYT?

> From the Tex view it is completely irrelevant which
> all-Standard-Roman-Character-Set encoding is used. For the purpose
> in question it is however necessary or at least of desire to add a
> few things to LY1 to make complete T1 fonts from fonts which provide
> some additional characters. This applies especially to Eng and A,
> E-ogonek which are usually not provided as composites. Postscript
> level 3 fonts will provide them.

How many or how few fonts do provide these characters?  If you use 8y
as a basis for virtual fonts you can fake them in T1 as usual with 8r,
if you just rely on reencoding, you can't.

> LY is not optimal in the sense that it contains several repeated
> codes and therefore has less space for additional useful characters
> which some fonts might provide - the advantage is mainly to cover
> the majority of standard fonts without the need of a special
> installation.

> If one keeps the little details in mind LY1+ works just fine.

At least, it's as good or as bad as using 8r.  Whether it's better
remains to be seen.

Cheers, Ulrik.