W3C home > Mailing lists > Public > www-svg@w3.org > November 2004

Re: Reconsider SVG 1.2

From: Will Pearson <will-pearson@tiscali.co.uk>
Date: Thu, 18 Nov 2004 08:35:28 -0000
Message-ID: <006d01c4cd49$e78c8830$36a3f70a@WILLXCFBVU8CQ8>
To: "David Woolley" <david@djwhome.demon.co.uk>
Cc: "SVG \(www\) list" <www-svg@w3.org>

David Woolley wrote:

>
>> One of the reasons that his is such a hot button issue for me is because
>> I have felt strongly for some time that SVG is "almost" complete, but is
>
> It is a long way from complete, even compared with PDF, as it doesn't
> include the semantic overlay, which may not be demanded by an unregulated
> (commercial) market, but certainly should be demanded by the regulated
> market that is created by accessibility legislation.  (The PDF term
> for this overlay is "tagged PDF".)

I agree semantics would be extremely useful in some use contexts, e.g. if 
people are intending to use SVG to replace HTML + CSS, in others, I'm not so 
sure.  Ultimately, SVG could be considered accessible without semantics. 
Users extracting meaning from visual parsing of the displayed document have 
learnt to infer meaning from various visual attributes, the same goes for 
pretty much any form of communication.  Therefore, provided those visual 
attributes can be conveyed non visually, there's no reason why a blind user 
couldn't associate meaning with the attributes.  Using current output 
modalities that are sequentially based, such as speech or Braille, this will 
be a long and tedious process that would make SVG, whilst accessible, not 
very usable, so semantics can play a big part in boosting the usability of 
SVG.

As an aside, it's down to the ua and authoring tool vendors to ensure their 
products are 508 compliant, but having accessibility included as part of the 
spec would help tremendously in this effort.

David Woolley wrote:
> At least one of the key parts of CSS, which is both most challenging
> to SVG and independent of the CSS syntax, is to meet accessibility
> requirements, namely user style sheets.

I agree with the basis of this, but not the proposed method.  User style 
sheets exist in HTML browsers, such as IE, yet quite a lot of users are 
unaware of this, don't know how to get a ua to use a user style sheet, and 
really don't know the first thing about creating user style sheets.  So, 
probably a better route to increase this sort of accessibility would be to 
have the ua alter the rendering, thus allowing users to select from a more 
user friendly dialog based interaction than having to write CSS.  This would 
also allow for the presentational aspects of SVG to be altered, such as 
disabling of animations, which would be another accessibility pre-requisite 
for some users.

I think we're getting some way with SVG accessibility.  We're not quite 
there yet, as things like keyboard navigation really need some thinking 
through, but I can see the light at the end of the tunnel.

Will 
Received on Thursday, 18 November 2004 08:38:55 UTC

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