Re: Checkpoint on testability

In broad summary I agree with the comments Kynn has made here. A couple of
notes added inine - look for LK, KB or CMN

On Fri, 22 Dec 2000, Kynn Bartlett wrote:

LK  >checkpoint x.2
  >Avoid use of alternative version of content that requires human effort to verify.
  >Example: Avoid when possible manually created images of text; use styled
  text instead.  Note that automated generation of images of text are
  allowed per checkpoint x.3
KB
  This worries me because of the vagueness; "avoid"..."when possible"
  is very much up to interpretation and gives little in the way of
  guidance, instead asking the web designer to make her own choice.
CMN
There is already a question of how to do this for WCAG 1.0 checkpoint 3.1. We
could apply whatever solution we end up with to this too, but I agree with
Kynn's concern about whether auto-generated images are the answer (and Note
ATAG, which explicitly prohibits relying on auto-generated alternatives in
many cases)
LK
  >checkpoint x.4
  >When alternative content is created manually, make specific
  correspondence between content and its particular alternative.

KB
  At one point we had talked about making relationships explicit in
  the markup or data model; is that what is meant here?  This may be
  a technique for another requirement. :)

CMN
I agree that this should be a requirement for other reasons. (Actually I
beleive it is covered under exposing the data model, since alternative [forms
of] content are included in that.)
LK
  >checkpoint x.5
  >When possible, Use only styles linked consistently to particular semantic objects.
  >Example: CSS rule that makes all Headings a particular style.
  >Negative Example: CSS rule linked to class.  Current CSS has no way to
  expose class semantics to user agent, so it takes human judgment to
  decide if the class is simply decorative, which is harmless, or is
  carrying information unavailable to user agents.

CMN
Part of this is covered under the requirement to include data in a data
model, part of it is covered under the requirement to benice to older
technology, and part of it in my opinion belongs in information about how to
use CSS. As has been pointed out elsewhere, use of ID attributes for
everything in CSS selecetion is roughly equivalent to use of font
attributes/elements.  Both can be repaired by a half-decent tool of course.
But I share Kynn's concern that saying not to use class is going too far. (It
does bring up the question of when should we expect people to upgrade...)

This also goes to the question of how to deal with transforamtions and so on.
One use case is XML, which is supplied with a selection of stylesheets via
CC/PP, but for which there is also a default transformation to XHTML, using
class to get around the fact that HTML may not have any particularly helpful
semantics to encode the information clearly. I am not convinced that this is
a bad approach...

Cheers

Charles

Received on Monday, 25 December 2000 19:41:32 UTC