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

On Wed, Nov 26, 2014 at 7:55 AM, John Birch <John.Birch@screensystems.tv>
wrote:

>  Understood…
>
>
>
> So by subsetted font you implicitly mean a font that is well formed in
> terms of its internal tables, not just a font that has been stripped of
> (unused) data to make it lightweight?
>

it is both: it must remain well formed, but glyphs and data for those
glyphs that aren't used by a document are removed; subsetted fonts are
commonly generated for embedding in PDF files these days by document
processing tools, but also have wide applicability on the web platform in
general; see http://www.subsetter.com/ for a tool that does subsetting of
web (woff) fonts;


>
>
> Best,
>
> J
>
>
>
>
> *John Birch | Strategic Partnerships Manager | Screen *Main Line : +44
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>
>
> *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 14:52
>
> *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 7:41 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
>
>
>
>
>
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