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Re: [Proposal] Delete VisualText and ColorText conformance labels

From: Ian B. Jacobs <ij@w3.org>
Date: Fri, 28 Jun 2002 12:18:13 -0400
Message-ID: <3D1C8C45.70006@w3.org>
To: Jim Ley <jim@jibbering.com>
CC: w3c-wai-ua@w3.org

Jim Ley wrote:
> "Ian B. Jacobs" <ij@w3.org>
>> > but I
>>>believe we need to highlight the issue that if you do it
> simplistically
>>>you also disable CSS-P, or you do it in a manner whereby CSS-P
> elements
>>>with a background also gain the users background colour.
>>Yes. Checkpoints 4.1, 4.2, and 4.3 require "global configuration"
>>(among other things). This means that one setting affects all
>>reference text size (but other text e.g., headers may still be
>>relatively larger), impose a single font family, and the user's
>>preferred fg and bg colors for text. This would apply to content
>>that is in the normal CSS flow and also positioned elements.
> Does it require that positioned elements which have a background colour
> set by CSS (other than transparent) should that become transparent, or
> should that also get the users set background colour.

The requirement of 4.3 is that for *all text*, the user be
able to specify foreground and background colors. This includes
elements rendered at any z-index.

UAAG 1.0 does not require that the user agent enable the user
to change the z-index of rendered boxes. The Note in 3.1
is explicit about this for background images:

    1. This checkpoint only requires control of background images for
    "two-layered renderings", i.e., one rendered background image
     with all other content rendered "above it".

Section 1.3 "Limitations of this document" states:

   "Background image interference. The requirement of checkpoint 3.1 
to allow the user to turn off rendering of background images does 
not extend to multi-layered rendering."

The UAWG intentionally avoided the world of multi-layered renderings
and acknowledges that as a limitation of UAAG 1.0. I personally
would not want the UAWG to reopen that discussion.

What would be very helpful for me is if you were to draft
text for me to include in the techniques document under checkpoint
4.3 (or 3.1), instructing UA developers on how to do the right
thing in case of multi-layered renderings such as those possible
with CSS-P.


  - Ian

>>Would it suffice to point this out in the Techniques document?
> I think so yes, It's just an area of concern to me, and not one I'm sure
> that UA developers are always aware of,  There's no page author technique
> to overcome the current behaviour other than never using CSS-P!
> Cheers,
> Jim.

Ian Jacobs (ij@w3.org)   http://www.w3.org/People/Jacobs
Tel:                     +1 718 260-9447
Received on Friday, 28 June 2002 12:21:03 UTC

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