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RE: [OpenType] Update on color/animation in OT via SVG; new W3C Community Group

From: Levantovsky, Vladimir <Vladimir.Levantovsky@MonotypeImaging.com>
Date: Mon, 28 Nov 2011 16:57:00 -0500
To: Sairus Patel <sppatel@adobe.com>, "public-svgopentype@w3.org" <public-svgopentype@w3.org>
Message-ID: <7534F85A589E654EB1E44E5CFDC19E3D1186E2956D@wob-email-01.agfamonotype.org>
On Wednesday, November 23, 2011 3:05 PM Sairus Patel wrote:
> To: public-svgopentype@w3.org
> Subject: RE: [OpenType] Update on color/animation in OT via SVG; new
> W3C Community Group
> 
> 
> b. Alternatively, a simple "g<glyphID>" e.g. "g0", "g1" scheme can be
>    specified to create the id value. This will be one less lookup that
>    needs to be done (i.e. the 'post' table lookup) which helps execution
>    speed. The font vendor is authoring the SVG OT font as an entirety
>    and requiring a certain pattern for the id name shouldn't be
>    burdensome, IMO.
> 

I like this approach a lot. Avoiding an additional lookup is definitely an advantage and with this glyph ID naming scheme, especially if it can be done with no additional changes to the SVG spec.

> 
> (The main point of my little interface sketch-up was that the SVG engine
> will only be queried by element id and not by character code, BTW, but
> I'm glad we're starting to discuss all the rest of the aspects of the
> interface!)
> 
> In my mind there are two aspects to this, glyph bounds and compositing
> with the rest of the page:
> 
> - Glyph bounds:
> 
>   The OT *font* bbox ('head' table xMin, etc) will indicate a rect which
>   no glyph, including its animation, must extend beyond. An OT engine or
>   application can examine this bbox and if it's too big can introduce
>   clipping or reject the font (as is the case today with CFF or TT).
>   While this may restrict font vendor creativity, it's what comes with
>   the OT model.

How would we know if the bbox is too big - e.g. some glyphs in existing calligraphic/casual script fonts have swashes that extend way beyond the normal glyph bounds. This would cause the overall font bounding box to be quite large, even though there are only few characters that have swashes. (I believe some of the versions of the Zapfino have the font name "Zapfino" defined as a single glyph ligature.)
And, alternatively, what would stop a font creator from adding one large glyph only for the purpose of increasing the size of font bbox?

Thank you,
Vlad
Received on Monday, 28 November 2011 21:57:26 GMT

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