Re: Using Computer Modern in Lout - some final questions

[Jeff Kingston]

> Ok, so why then do they bother creating all these various AFM files
> corresponding to different sizes from Metafont?  Is it because the font
> characteristics don't scale optically and vary with different sizes?

I suppose so.  Even though the AFM file does not represent any particular
size, there is nothing to stop an application from giving the file a name,
or including a comment in it, that identifies it as being intended for
use at a particular size.  I'd like to know whether many systems are
actually using different verions for different sizes, and if so whether
there is any standard for indicating that this is wanted.  These issues
popped up on the list once before, but the answer seemed to be that
Adobe did something then discontinued it, and I lost track of it there.

> > Probably not for Lout.  Do you know of other systems that make it easier to
> > add fonts?  How do they make it easier?
> 
> At first I thought you were joking, and now I'm not so sure.  I think
> dragging or copying TTF or OTF files to a Fonts directory is far easier
> than:
> 
> 1) Duking it out with fontdefs.ld and trying to understand exactly how
>    these fields correspond to what Lout wants to see.
> 
> 2) Having to generate PFA files which other tools require and making sure
>    the filenames match whatever was in the AFM file.
> 
> 3) Having to run includeres on the resultant output of Lout in order to
>    actually get the font content included in any output downstream.
>
> If I have access to Adobe Font Folio, am I supposed to generate those
> fontdef entries by hand?  There are over 2000 fonts alone in TrueType and
> OpenType format.

I wasn't joking.  Presumably equivalents of all these things are done
behind the scenes in systems that work off directories of font glyph
files.  You have to consider Lout as part of a tool chain, and what
you have here is the absence of a useful auxiliary tool rather than
a defect of Lout itself.

> I was going to write a script that automatically generated a fontdef entry
> given an AFM file, but I don't actually think it's very straightforward
> when you consider fonts like Computer Modern that were generated based on
> sizes in the original form.

You're going to have to choose one and go with it only.

The main point of interest for me in all this is how one could deduce the
fontdef entries from a directory of font files.  Taking a sample entry:

    { @FontDef
        @Tag { AvantGarde-Base }
        @Family { AvantGarde }
        @Face { Base }
        @Name { AvantGarde-Medium }
        @Metrics { AG-Md }
        @Mapping { LtLatin1.LCM }
    }

the two things that stand out as non-trivial are @Face { Base } and
@Mapping { LtLatin1.LCM }.  @Face basically determines what you get
when you ask for the ordinary face of a font family, or the bold
face, or whatever.  How do these automatic systems deduce this
information?  Do the font files contain the equivalent of the
Weight entry in the AFM file, or what?

The @Mapping field I guess is obsoleted by the use of Unicode -
there is only one @Mapping then, namely Unicode.  So this field
is a case of Lout showing its age.

Jeff