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Proposal for action Re: Call for Consensus (CfC): Comments on the MSE CR

From: Chaals McCathie Nevile <chaals@yandex-team.ru>
Date: Fri, 11 Dec 2015 13:39:31 +0300
To: "HTML Accessibility Task Force" <public-html-a11y@w3.org>, "W3C WAI Protocols & Formats" <public-pfwg@w3.org>, "James Craig" <jcraig@apple.com>
Cc: "Janina Sajka" <janina@rednote.net>
Message-ID: <op.x9g6j5c5s7agh9@>
On Fri, 11 Dec 2015 12:54:21 +0300, James Craig <jcraig@apple.com> wrote:

>> 1.)	The diagram in this document should have a longdesc.
> -1. This is why we can't have nice things.

Well-described images, and descriptions people could readily find, and  
avoid, at will, would indeed be nice.

Even better accessibility would be even nicer, but it seems we can't have  
that soon :(

>> If possible, the diagram itself should also be created using accessible  
>> SVG markup.
> Is your recommendation intention really SVG+longdesc? That's how this  
> reads.

That's what was proposed at the meeting. In particular, VoiceOver users  
generally can't get the benefit of a longdesc, but it is possible to make  
some types of SVG somewhat accessible to them, and the image here seems to  
be a good candidate (if Safari follows SVG links and Firefox implements  
tabindex). Meanwhile, users of other screenreaders can get a longdesc, but  
except for blink-based browsers it's pretty hard to make something like  
SVG usefully accessible to them.

> Instead of an overly prescriptive proposal of one possible solution  
> ("You must use @longdesc, and ideally SVG."), this should be phrased,  
> ~"The diagram in the document should be made accessible." How they  
> choose to do that is irrelevant. Neither @longdesc nor SVG is a  
> requirement for accessibility.

That's correct in principle, and I would be happy if we made that  
statement. But we'll then get a question on how to do so in practice, at  
which point it seems we come to inherent accessibility, which means SVG,  
but also doesn't work very well for most people so we need a fallback,  
which is a description. For obvious reasons people should be able to  
identify and skip over the description the third or fourth time they read  
the document. You are right that longdesc isn't the only way to achieve  
that, and in many cases it *should* be used in conjunction with a   
description that's part of the normal page content.

> You should also include some examples of how to make both vector and  
> bitmap images accessible. You're welcome to use the options I've  
> compiled here. Note: 2 of the 5 examples do use SVG.

I think it would be more useful to include some examples of how to make  
the particular image under discussion more accessible. I'd be happy to  
look for a bit of time to try and do this. I'd be equally happy if several  
people had a go, so we could compare concrete examples and try to find all  
the problems and good points in each.


Charles McCathie Nevile - web standards - CTO Office, Yandex
  chaals@yandex-team.ru - - - Find more at http://yandex.com
Received on Friday, 11 December 2015 10:40:15 UTC

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