W3C home > Mailing lists > Public > www-svg@w3.org > June 2011

Re: proposal for text layout with positioned glyphs, anchoring and bidirectionality

From: Cameron McCormack <cam@mcc.id.au>
Date: Wed, 22 Jun 2011 17:48:06 +1200
To: John Daggett <jdaggett@mozilla.com>
Cc: www-svg@w3.org
Message-ID: <20110622054805.GK18244@wok.mcc.id.au>
Hi John.

John Daggett:
> I think there's a fundamental problem with this feature and the way it
> was originally designed. It really should have been veto'd long ago
> because there's no way to make this work correctly for complex scripts
> and it's based on the naive model of text layout where all characters
> map to a single glyph and are placed sequentially along a run of
> text.
> 
> The key problem is that you're attempting to map *glyph* advances to a
> string of *characters*.

I think you’re exactly right about this.  We’ve been talking in the WG
over the last few weeks about this, and how we would need glyph
selection and placement rather than going by a string of characters to
support the precisely laid out text use case.  Rik Cabanier is planning
on presenting a proposal for this at our next F2F.

> If the SVG group doesn't want to deprecate this feature, then I'd say
> it would be best to put a warning note that this feature will break in
> the presence of complex layout, rather than trying to define it in a
> way that overrides the results of complex layout.

I think including a warning is a good idea.  My intention with the
proposal that I wrote up was to make the existing text layout and
positioning features of SVG more well defined and saner to implement.
Existing content does rely on the use of multiple x/y values on text, so
we need to have it defined, even if it is not useful beyond simple
cases.

Thanks,

Cameron

-- 
Cameron McCormack ≝ http://mcc.id.au/
Received on Wednesday, 22 June 2011 05:48:43 GMT

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