Re: Font question

[Taco Hoekwater <taco@elvenkind.com>]

Marcin Borkowski wrote:
> OK, so the first part of my questions about mfonts.pdf;)
> 
> Thank you in advance for the answers; I'd like to stress that I'm not in
> a hurry, so please take your time!  Also, as I said, I have nothing
> against being "redirected" to some other part of documentation in case
> it is easier than to write a full answer here.
> 
> 1. Do I get it right when I think that \definefontsynonym takes 2 or 3
> arguments, and:
> 
> When given two, they mean: (1) the synonym being defined
> and (2) an earlier defined synonym being a "replacement text" for (1);
> 
> When given three, (1) is as above, (2) is the filename of the font (tfm
> I guess?) and (3) contains some low-level options like the encoding 

That sounds right.

> (are there any other options available?)

I think you can also define:

   mapping  % for xetex (?)
   handling % for an experimental pdftex font feature
   features % mostly for mkiv

But all the first two are somewhat experimental, and features are only
really useful for opentype fonts. All three are relatively new and not
documented in mfont.pdf yet.

> 2. What does exactly sa mean?  Do I get it right when I think that it's
> the factor by which the "body font size" - i.e., some constant dimen
> parameter defined for the whole document (or environment) - is
> multiplied?  Does the "laziness" of sa mean that the actual scaling will
> happen _after_ the definition of the body font size, which might be e.g.
> different for different components of a product within a project using a
> common environment?  And what is mo?

sa stands for "scaled at", mo stands for "mapped on".

One of them (I think sa) is a multiple of the value you specify at
   \setupbodyfont[..] or \switchtobodyfont[..],
the other is (I think) in relation to the actual current font size
(so it is different whether \tfx or \tfa is in effect).

> 3. What are the arguments to \definebodyfont?

  #1  size (5pt ... 12pt default)
  #2  family (rm ss tt mm hw cg)
  #3  font definitions (tf = ..., etc.)

> 4. What are the relations between \definefontsynonym, \definefont and
> \definebodyfont?

things defined with \definefontsynonym can be used in the right hand
side of assignments in arg #3 of \definebodyfont, and in the #2
argument of \definefont.

\definefont has no real relation to font switching, it is just a
low-level shortcut for a specific font, much like a bare \font
command in plain TeX, except that it allows synonyms and sa/mo.

\definebodyfont is used to build up font collections

> 5. I can understand neither the paragraph right before the
> \definebodyfont example on page 4 of mfonts.pdf, nor the example itself.

That paragraph is a bit confusing to me as well. Browsing through
type-siz.tex may help (in tex/context/base).

Best wishes,
Taco
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