- From: Al Gilman <alfred.s.gilman@ieee.org>
- Date: Wed, 10 Sep 2008 11:13:55 -0400
- To: Dave Singer <singer@apple.com>
- Cc: HTML WG <public-html@w3.org>, Doug Schepers <schepers@w3.org>, Karl Dubost <karl@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>
Sorry to be slow in responding. On 25 Aug 2008, at 6:51 PM, Dave Singer wrote: > > At 17:23 -0400 22/08/08, Al Gilman wrote: >> >> If the agent putting the markup together really doesn't have a >> clue (not the Flickr case) >> then I don't really have a problem with it being absent and non- >> conforming. > > I think this is a fundamental disconnect. > > I rather fear we might have the following equation in play: > > "There is a tool available at the syntax level for applying > pressure to people to write their documents certain ways: it is > called syntactic conformance. We need to apply pressure to get > meaningful alt text provided for all images. We should therefore > use syntactic conformance checking." No, it's more like "we shouldn't put non-syntactic cases into the syntax." The case where the author tool can repair but doesn't trust that its repair meets WCAG is not a syntax case, it is an operational and semantic case distinction. > The problem is that would be asking a syntactic conformance check > to do a semantic function, and it doesn't work. The history is it does work. That is to say, requiring @alt does more good for users with disabilities than it does harm. What accessibility experts have told you otherwise? HTML5 is trying to write in non-syntactic cases into the format spec to address the problem of semantically-bogus text appearing there. This is a usage problem that doesn't belong in the format spec. You and I are in flaming agreement, here. >> No, it does have a text alternative for the image. > > You lost me. What does it (the UA) have (in this case: alt="auto- > uploaded}")? It has {auto-uploaded} or somesuch; this is not an > text alternative to the image itself. Let me explain. If it's not of some plausible use to the listening user to figure out what is going on in the page, there is no point putting it in the page. Even in a distinguished markup that expresses a demurrur about the WCAG sufficiency of the text provided. The point is that the appropriate decision point for the AT to attempt to overcall the server-side repair of this under-performing situation is - not on learning that the @alt is a server-side repair, - but rather if the user challenges the @alt when presented, and asks for more info. In terms of doing something simple, the server-side tool has better context, has a better shot at, making a repair than does the client-side tool. Only by heroic measures can the client-side tool expect to explain this image better than the server did. And it can always do that, if it has the capability. But there is no point expending those compute resources (even in the rare chance that they are available) on every repaired-alt image coming over the wire. Only when the user interactively indicates that they do need better information about *this* image is it worth going to those lengths. The subtleties of when and how the server-side authoring tool should put what text in the @alt as a repair, and how (in EARL?) to express a demurrur about what it has done, belongs in authoring techniques below Recommendation grade of normativity. This doesn't create a case for missing @alt so the syntax need not get involved. The whole HTML5 section on how to populate @alt goes far beyond syntax into semantics. A recorded issue for the syntax is whether missing @alt should be a syntax violation. This case does not bear on that issue. > > > > -- > David Singer > Apple/QuickTime >
Received on Wednesday, 10 September 2008 15:14:36 UTC