Re: [css3 fonts] font-specific features

Tal Leming wrote:

> >  <font-family> :== font family name, quoted or unquoted
> >  <font-variant-value> :== the name of one of the font-specific font-variant values (e.g. swash, styleset, annotation)
> >  <value-list> :== <value-name> <integer>+
> >  <value-name> :== a user-defined identifier used to describe the numeric value
> >  <integer> := an integer value greater than 0
> >
> > Multiple integers would only be permitted for font-variant values that
> > permitted multiple values (e.g. styleset, character-variant).  Other
> > font-variant values would only permit a single value.
> >
> >  @font-feature-values My Lovely Font {
> >    swash: swishy 1, flowing 2;
> >    stylistic: long-k 2;
> >    styleset: alt-g 1, alt-m 3, curly-quotes 5, code 4 7 9;
> >  }
> 
> This makes sense. The only part that I'm hung up on is  "code 4 7 9". 
> How does that tie into the GSUB data? Does it mean this:
> 
>    ss04, ss07 and ss09 are all on for each glyph being processed

Yes.  Note that this is *only* specifying the meaning of "code" used
within a styleset(xxx) value.

For example:

  code { font-variant: styleset(code, alt-g); }

This implies that for the content of <code> tags, ss01, ss04, ss07,
ss09 would be enabled.

> If so, how does the author specify a particular index from a GSUB
> Lookup Type 3 for a styleset?

If by this you mean some form of stylistic set that allows multiple
values per feature tag (e.g. ss04=7) then that's not supported by the
current proposal, an author would need to use the low-level
font-feature-settings property.  I think this is probably more
relevant to fonts with character variants that map all variants for a
given character to a common cvNN feature tag (e.g. all variants of
alpha map to cv01).

> I'm probably missing something simple...

Likewise... ;)

John Daggett