Re: Embedded fonts + generic font families

Hi Nigel,

> > If the generic family name default is specified (or implied by an
initial value), then its typographic characteristics are considered to be
implementation dependent;

What about the clause:

"""
When selecting among font resources that satisfy the font selection
criteria, font resources that are referenced by a font element have
priority over application or system supplied font resources.
"""
I thought it would be weird if the author could not provide a default font.

Best,

-- Pierre


On Thu, Jan 24, 2019 at 10:25 AM Nigel Megitt <nigel.megitt@bbc.co.uk>
wrote:

> Hi Pierre,
>
> good question!
>
> The text of <generic-family-name>
> <https://www.w3.org/TR/ttml2/#style-value-generic-family-name> in TTML2
> says:
>
> > The resolution of a generic family name to a concrete font instance is
> considered to be implementation dependent, both in the case of content
> authoring and content interpretation.
>
> and
>
> > If the generic family name default is specified (or implied by an
> initial value), then its typographic characteristics are considered to be
> implementation dependent;
>
> which I think any way you play that through means that it is not specified.
>
> Looking at the semantic derivations, XSL refers to CSS, and CSS2
> <https://www.w3.org/TR/2011/REC-CSS2-20110607/fonts.html#font-family-prop>
> says:
>
> > Font family *names* that happen to be the same as a keyword value
> ('inherit', 'serif', 'sans-serif', 'monospace', 'fantasy', and 'cursive')
> must be quoted to prevent confusion with the keywords with the same names.
> The keywords 'initial' and 'default' are reserved for future use and must
> also be quoted when used as font names. UAs must not consider these
> keywords as matching the '<family-name>' type.
>
> So by that rule there would be a difference in your example between the
> handling of tts:fontFamily='default' (generic font family name) and
> tts:fontFamily='"default"'  (non-generic). I have not checked if later
> iterations of CSS have modified this rule; this is the version of CSS2 that
> is referenced by TTML2.
>
> It is not clear to me if we apply the same rule in TTML2. Incidentally
> this is one of the effects of our non-normative referencing of semantic
> basis, which the Director queried in 2018. As part of any refactoring of
> TTML we should think about whether we can strengthen the normative
> definitions of style attributes.
>
> kind regards,
>
> Nigel
>
>
> ------------------------------
> *From:* Pierre-Anthony Lemieux [pal@sandflow.com]
> *Sent:* 24 January 2019 09:07
> *To:* TTWG
> *Subject:* Embedded fonts + generic font families
>
> Good morning/evening,
>
> Say the following is present in a TTML2 document:
>
>   <resources>
>     <font family="default" range="u+20-7f,u+90-9f">
>       <source src="http://example.com/fonts/default.otf" type="font/otf"/>
>     </font>
>   </resources>
>
> In the following snippet, is a presentation processor expected to use the
> embedded font, or is the font selection sill left to the implementation?
>
> <p tts:fontFamily="default">font above or application-selected?</p>
>
> Best,
>
> -- Pierre
>
>
>
> ----------------------------
>
> http://www.bbc.co.uk
> This e-mail (and any attachments) is confidential and may contain personal
> views which are not the views of the BBC unless specifically stated.
> If you have received it in error, please delete it from your system.
> Do not use, copy or disclose the information in any way nor act in
> reliance on it and notify the sender immediately.
> Please note that the BBC monitors e-mails sent or received.
> Further communication will signify your consent to this.
>
> ---------------------
>