[Fontinst] Latin Modern fonts: small caps and accents

[cfrees at imapmail.org]

On Fri 21st May, 2010 at 17:59, Lars Hellström seems to have written:

> Dr. Clea F. Rees skrev:
>> I am trying to update CFRLatinModern for version 2.004 of Latin Modern
>> (included in TL 2009 which I recently updated to). While I'm at it, I
>> was hoping to resolve some of the issues which I or others raised about
>> the earlier version of the package. (The aim of the package is to make
>> various features of the fonts, especially different styles of figures,
>> easily accessible in LaTeX.)
>> 
>> The following is bugging me a lot: when using the small-caps version of
>> the font, accent placement for characters which  must be created "on
>> the fly" are wrong. Not only are the accents too low for the small-caps
>> themselves, they are too low for the capital letters as well. So if I'm
>> using T1 encoding, \^A is fine but \^W and \^Y are not; similarly for
>> \^a versus \^w and \^y.
>> 
>> I don't expect these characters to look great because TeX is creating
>> them on the fly, but my package creates output markedly worse than that
>> produced by using lmodern itself and I cannot figure out why. The
>> accents are placed much lower so they run into the letter below.
>> 
>> This isn't a problem for the non-small-caps variants of the fonts - the
>> output produced by my package doesn't look any worse than that output
>> by lmodern for these characters.
>> 
>> I did notice that fontdimen 10 and 12 differ in lmr10.afm and
>
> Numbered fontdimens in AFMs? News to me, unless you mean AFM keywords 
> corresponding to acccapheight and maxheight.
>
Probably I'm explaining badly. There are a bunch of lines starting:
Comment TFM fontdimen <number>: <number> (text)

>> lmcsc10.afm. These are both smaller in the case of lmcsc10.afm which
>> seems odd. But I'm assuming this is just my ignorance since lmodern is
>> obviously based on these dimensions and everything works fine there.
>
> One fontdimen that is likely to be important is xheight (fontdimen 5), as 
> TeX's \accent primitive assumes the accent character specified is in the 
> proper position for a glyph with \height{}=xheight. If for example the 
> smallcaps xheight is larger than the regular xheight, but you're using the 
> regular accent in the smallcaps font, then you would get the effect that it 
> is placed too low.

grep XHeight lmr10.afm lmcsc10.afm gives:

lmr10.afm:XHeight 430.55556
lmcsc10.afm:XHeight 513.88889

grep xheight lmr10.afm lmcsc10.afm gives:

lmr10.afm:Comment TFM fontdimen  5: 4.3055	(xheight)
lmcsc10.afm:Comment TFM fontdimen  5: 4.3055     (xheight)

So would fontinst be using the first or the second?

I'm using the smallcaps accent in the smallcaps font; the regular
accent in the regular font. I don't think I'm inadvertently mixing them.

Thanks!

- cfr

> Lars Hellström
>
>> I'm using fontinst to generate the font files needed from the relevant
>> afms. Because this takes a very long time to complete on my machine,
>> I don't really want to do this by trial-and-error alone. Besides, I
>> have no idea what to try - am definitely out of my depth.
>> 
>> Any help will be greatly appreciated. My package works OK for English
>> but it really looks bad for Welsh...
>> 
>> - cfr
>> 
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