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Re: SVG 1.2 Comment: Detailed last call comments (all chapters)

From: Jim Ley <jim@jibbering.com>
Date: Fri, 5 Nov 2004 16:09:32 -0000
To: www-svg@w3.org
Message-ID: <cmg8kd$35l$1@sea.gmane.org>


"Nigel McFarlane" <nrm@kingtide.com.au> wrote in message 
news:418BA2B7.7030803@kingtide.com.au...
> Rather than pick nits over <canvas> or other tags, it would
> be better if the "yea" sayers would defend SVG by explaining
> how it *can* support accessibility, UA content extensions, and
> XForms, and how much CSS it has to lean on to do so. How much
> can it do?

How SVG can support accessibility of a stock graph (something that Ian 
stated was better done with a canvas element) can be easily demonstrated. 
You can use sXBL to convert source data in an appropriate format (I imagine 
you'll find something appropriate at 
http://www.service-architecture.com/xml/articles/finance_xml.html ) to its 
representation.  However, even without this ability to re-use known 
semantics, the SVG representation can be more accessible, since each element 
of the graph can be labelled with a title and description, which is then 
available to AT's as a user interacts with the graph.  (e.g. Vladimir 
Bulatov's bump printer described in 
http://www.svgopen.org/2004/papers/SVGOpen2004MakingGraphicsAccessible )

Even without a title/description, information can be better obtained from an 
SVG document, than a bitmap (which is all canvas has, it just paints bits 
onto a canvas, there's no state).

> Can SVG perform accessibly without leaning on CSS?

They're both rendering languages and completely orthogonal, in SVG the 
semantics are in the rendering - and in CSS there are no semantics in the 
rendering, there's nothing to lean on each other.  CSS is actively harmful 
to accessibility in SVG, you can't style a rendering language and maintain 
accessibility (If you're not aware of the reasons why, you cansee the 
problems the CSS cascade produces described in 
http://jibbering.com/2002/8/text-mixup.svg )

Making SVG graphics accessible is not about CSS  - CSS isn't about making 
anything accessible, it just removes the problem of seperating the rendering 
from the semantics.

Jim.
Received on Friday, 5 November 2004 16:09:56 UTC

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