- From: Charles McCathieNevile <charles@w3.org>
- Date: Mon, 17 Jul 2000 00:12:16 -0400 (EDT)
- To: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
- cc: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
Here is how I am thinking about it... The goal is to provide information that can be used by anyone, anytime, anywhere, and for them to have the information presented in an appropriate way for their needs. So the most general priciple is to make explicit what the information to be conveyed is and seperate presentation(s) out, so that transformation to appropriate presentation is achievable. Until User Agents are clever, and can present things in a different for mat by themselves, we need to make sure that we provide information in the various formats that might be required - text, metadata, audio, graphics, braille, etc. In fact, we can do some of these things - text can be turned into braille or speech fairly reliably, so we don't need to explicitly generate those. We need to have text and metadata, and audio, and graphics, and video in the presentation so we can give it to the user however. Since we don't expect this to happen in the next year or two, we don't bother putting "until user agents" at the front of the requirement. Actually that's a bit of a conceit - some of this stuff can be done now. It just takes so long to settle on it that we are better off agreeing on a baseline than trying to capture what is constantly shifting. And we get the same sort of thing through the rest of the guidelines - requirements that we have because user agents aren't clever enough yet to simply read a presentation and reformat it into whatever we need. One of the things I like about the new set we are working with is that we have got rid of the until user agents stuff. To do that properly, we need to decide (as has been recognised) what the minimum acceptable capabilities are in a user agent. In fact, that might vary ffrom language to language - what we settle for in XHTML might be very different from what we accept from an SVG user agent, or a flash player, or whatever. cheers Charles McCN On Mon, 17 Jul 2000, Jason White wrote: This has been a good discussion. The current draft avoids the "until user agents" qualification everywhere except in relation to auditory descriptions. Principle 6, which covers interim measures, is however partly covered by an implicit "until user agents" qualification, for example with respect to automatically refreshing, blinking and flickering content--these are important features that need to be controlled in circumstances where user agents fail to do so. Perhaps one way of expressing it, in rough terms, would be: "If you suspect that user agents may not provide control over these features (blinking, flicker, etc.), don't use them or provide an alternative version of the content". Naturally, this can be expressed in more formal terms and I would volunteer to rewrite some of the guidelines under Principle 6 accordingly. I still think Principle 1 needs work. -- Charles McCathieNevile mailto:charles@w3.org phone: +61 (0) 409 134 136 W3C Web Accessibility Initiative http://www.w3.org/WAI Location: I-cubed, 110 Victoria Street, Carlton VIC 3053 Postal: GPO Box 2476V, Melbourne 3001, Australia
Received on Monday, 17 July 2000 00:12:22 UTC