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Re: TT and subtitling

From: Chris Lilley <chris@w3.org>
Date: Fri, 31 Jan 2003 20:48:47 +0100
Message-ID: <130976800609.20030131204847@w3.org>
To: public-tt@w3.org, "Glenn A. Adams" <glenn@xfsi.com>
CC: robin.berjon@expway.fr

On Friday, January 31, 2003, 5:52:14 PM, Glenn wrote:

GAA> Yes, this is certainly a possibility. However, I wonder if these
GAA> capabilities have indeed been implemented in any small footprint
GAA> devices yet.

Uh, yes. We would not have got out of Candidate recommendation
otherwise. So, there are implementations from BitFlash and from Zoomon
and from KDDI (three or four different implementations!) and from
Nokia and from CSIRO; and from members of the public, too. All of
these implement SVG Fonts.

Plus of course the SVG Basic implementations from CSIRO and Intesis
and Bitflash.

GAA> I have heard from some sources that "SVG Tiny is not nearly tiny
GAA> enough", and the reason the tend to give is the inclusion of the
GAA> basic font module.

Well, we went over all that in the SVG WG and the basic font modukle
ended up being retained. However, we restricted the content such that
fonts had to be provided along with the conten not referenc ed in a
separate file. This helps streaming, minimiuses caching requirements

GAA> One potential issue with the SVG font format is its apparent
GAA> lack of support for bitmap as opposed to outline glyph representations.

That is a strength, not a feature. How are you going to cope with a
range of display sizes and resolutions with a bitmap font?

GAA> I would like to have seen a mechanism in SVG fonts that would support
GAA> the use of a "data:..." URI in which one may embed a bitmap directly.
GAA> Perhaps there is such support and I simply haven't discovered it.

You can use data URIs but you cannot embed bitmaps into the font. This
was discussed, evaluated and found not to be a good solution.

GAA> Of course I realize very well the lack of device interoperatibility
GAA> entailed by sole reliance upon the use of prerasterized glyph images;
GAA> however, this is still a common mechanism used in a number of regions,
GAA> such as in East Asia.

Because its the only way to get a complete glyph coverage into a small
memory footprint - small and ugly fonts at a single resolution. The
solution is to not require the device to store a complete Unicode
coverage; the set of glyphs needed for the content is sent, rendered,
and thrown away.

 Chris                            mailto:chris@w3.org
Received on Friday, 31 January 2003 14:48:49 UTC

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