Re: Precedence in tts:fontFamily

TTML1 defers to XSL-FO which defers to CSS2 the semantics of font mapping.
This is done implicitly in [1] via:

The semantics of the style property represented by this attribute are based
upon that defined by [XSL 1.1] <https://www.w3.org/TR/ttaf1-dfxp/#xsl11>, §
7.9.2.

[1] https://www.w3.org/TR/ttaf1-dfxp/#style-attribute-fontFamily

TTML2 has a placeholder to document this process more explicitly [2]. See
the second editorial note: *Font Selection*.

[2]
http://w3c.github.io/ttml2/spec/ttml2.html#style-attribute-fontSelectionStrategy



On Thu, Jul 7, 2016 at 11:11 AM, Pierre-Anthony Lemieux <pal@sandflow.com>
wrote:

> Hi Glenn,
>
> > order definitely matters
>
> Ok. Makes sense to me. I could not find a clear statement to that
> effect in TTML1. Do you see one? If not, perhaps add one in the next
> errata and updated TTML2 accordingly?
>
> Best,
>
> -- Pierre
>
> On Thu, Jul 7, 2016 at 10:08 AM, Glenn Adams <glenn@skynav.com> wrote:
> >
> >
> > On Thu, Jul 7, 2016 at 10:53 AM, Pierre-Anthony Lemieux <
> pal@sandflow.com>
> > wrote:
> >>
> >> Hi all,
> >>
> >> (Hopefully) quick questions: (i) is the ordering of values in
> >> tts:fontFamily significant and (ii) does familyName take precedence
> >> over genericFamilyName?
> >
> >
> > order definitely matters
> >
> >>
> >>
> >> For instance, are the following two declarations equivalent?
> >>
> >> tts:fontFamily="proportionalSansSerif,Arial"
> >> tts:fontFamily="Arial,proportionalSansSerif"
> >
> >
> > it depends; if proportionalSansSerif maps to Arial (on some
> implementation)
> > then they would be equivalent (on that implementation)
> >
> >>
> >>
> >> ... and what is the expected outcome of the following?
> >>
> >> tts:fontFamily="proportionalSansSerif,proportionalSerif"
> >
> >
> > if proportionalSansSerif maps to F1 and proportionalSerif maps to F2,
> and if
> > the character maps (cmap tables) of both F1 and F2 define mappings for
> the
> > same set of characters, then the above would be equivalent to:
> >
> > tts:fontFamily="proportionalSansSerif" or
> > tts:fontFamily="F1"
> >
> >>
> >>
> >> Thanks,
> >>
> >> -- Pierre
> >>
> >
>