[XeTeX] Some fontspec details

[Will Robertson]

[I'm sending this reply to the XeTeX list. Hope you don't mind!]

albert at gv.pl wrote:

> Is it correct to use general
> LaTex declarations \large, \Large, \huge etc to change font size within
> the main document or should I use other, fontspec specific commands.

Ah yes. That would be a good thing to add to the docs.
The answer is "yes" - fontsize changing commands have not been affected, 
and there are no fontspec commands for changing the size of a font in 
the text of a document (well, besides the scale option, but that's not 
what it's for).

fontspec doesn't define any commands that preclude you from using the 
old commands you used to use - this even means you can use
    \fontencoding{T1}\fontfamily{ppl}\selectfont
if you want to use LaTeX's Palatino font.

[Now I go into some technical details that probably no-one's interested 
in, but I'll write them down just in case.]

Basically all the package does is define a new (unique) font family for 
every combination of features you request. I don't use that name in the 
user interface because it would be too complex to type in your document: 
After you've said

    \fontspec[Mapping=text-text,
              LetterCase=SmallCaps,
              NumberCase=Lowercase]{Hoefler Text}

You could well type into your document (something like)

    \fontfamily{HoeflerText:+map=text-text+3,3+12,0}
    \selectfont

for the same effect as repeating the original command.

Since I wrote the package, I've discovered that you can overwrite font 
family definitions (something LaTeX prevents you from doing), but I've 
stuck with defining separate families for separate feature sets for now. 
(I'm not sure what the ramifications of removing this would be.)

Really, some TeX guru really needs to go over the package and work out 
what could be done better. As my first TeX coding experience, I'm very 
sure it's quite rough around the edges. Luckily XeTeX is slow enough 
that inefficiencies in my package don't seem to show up too much :)

Regards,
Will