Re: [ttml2] embedded content, background image styling, other edits

On Wed, Nov 26, 2014 at 7:41 AM, John Birch <John.Birch@screensystems.tv>
wrote:

>  That note may also need to be referred to from the font-face section too?
>
> It would seem that (except for ASCII / LATIN 1) as mentioned, the use of
> the Unicode ‘range’ element becomes almost mandatory when a resource is
> referenced internally?
>

Not really. The only use of family, style, weight, and range attributes on
<font/> are to allow font selection processing to reject use of a font
without actually having to access/load the font. Further, the range
element, if specified would only indicate the character range supported by
a subsetted font (if it were indeed subsetted).

In the absence of a range attribute (not element) the font selection
algorithm *may* need to load the font resource and use the internal CMAP
tables (or equivalent) to determine the effective range(s) of coverage. But
if that font were later in the prioritized list of font candidates (for
selection processing) then it may not even be accessed (or loaded) if a
font earlier in that list satisfies the selection criteria.

So, the answer about whether range is useful or not: it depends.


>
>
> Best,
>
> John
>
>
>
>
> *John Birch | Strategic Partnerships Manager | Screen *Main Line : +44
> 1473 831700 | Ext : 2208 | Direct Dial : +44 1473 834532
> Mobile : +44 7919 558380 | Fax : +44 1473 830078
> John.Birch@screensystems.tv | www.screensystems.tv |
> https://twitter.com/screensystems
>
>
> *Visit us at BVE, Excel London 24-26 February 2015 Stand No. N19*
>
> *P** Before printing, think about the environment*
>
> *From:* Glenn Adams [mailto:glenn@skynav.com]
> *Sent:* 26 November 2014 14:37
> *To:* John Birch
> *Cc:* public-tt@w3.org; tai@irt.de; nigel.megitt@bbc.co.uk
> *Subject:* Re: [ttml2] embedded content, background image styling, other
> edits
>
>
>
>
>
> On Wed, Nov 26, 2014 at 7:30 AM, John Birch <John.Birch@screensystems.tv>
> wrote:
>
> Thanks! I'll follow up Nigel's proposal. As indicated, I don't view it as
> a strong requirement (for STL files)... Not sure about this concept for
> other large resources (like fonts)...
>
>
>
> btw, for fonts, you should be using subsetted fonts, i.e., containing only
> glyphs for characters used in a document; with an ASCII or LATIN-1 only
> font, this won't make much difference, but for modern Unicode fonts
> covering multiple scripts or for CJK fonts, this makes a huge difference;
>
>
>
> i will add a note in the section defining the font element reminding
> readers of this fact
>
>
>
>  This message may contain confidential and/or privileged information. If
> you are not the intended recipient you must not use, copy, disclose or take
> any action based on this message or any information herein. If you have
> received this message in error, please advise the sender immediately by
> reply e-mail and delete this message. Thank you for your cooperation.
> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
> Registered Office: The Old Rectory, Claydon Church Lane, Claydon, Ipswich,
> Suffolk, IP6 0EQ
>    ­­
>