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Re: background images

From: Charles McCathieNevile <charles@w3.org>
Date: Thu, 22 Jun 2000 02:15:10 -0400 (EDT)
To: Ian Jacobs <ij@w3.org>
cc: "Leonard R. Kasday" <kasday@acm.org>, w3c-wai-gl@w3.org
Message-ID: <Pine.LNX.4.20.0006220210330.31247-100000@tux.w3.org>
This seems to highlight the problem with providing substantial amounts of
exemplary material in the guidelines-  people assume that it is
comprehensive. There is a literal requirement in checkpoint 1.1: "Provide a
text equivalent for every non-text element." A background image is a non-text
element (clearly this depends on the definition, and it may be worth
providing an explicit definition that makes clear why a paragraph element
with text content and an image element providing a representation of text
content are different).

Charles McCN

On Wed, 21 Jun 2000, Ian Jacobs wrote:

  "Leonard R. Kasday" wrote:
  > 
  > I just came across a page with a background image
  > 
  > <body background="image.gif">
  > 
  > There was no ALT text... indeed there's no way to add alt text here.
  > 
  > Backgrounds are often just decoration, but this one had actual textual
  > info.  So we need a guideline.  E.g. to
  > 
  >   1. limit background images to pure decoration  or
  > 
  > 2.  include any info in the background image in the text of the page,
  > possibly invisible text or
  
  Here's some discussion on this topic from June 1999, starting
  with a suggested clarification [1]:
  
        | I think the WG should strengthen a statement
        | in the guidelines that any important 
        | content inserted by a style sheet be available in the 
        | document source as well (rationale: device-independence,
        | users can override styles, etc.)
  
  The example given in that email is that W3C Recommendations use
  a background image in the upper left hand corner to indicate
  that they are Recommendations. This sounds like your issue.
  
   - Ian
  
  
  [1] http://lists.w3.org/Archives/Public/w3c-wai-gl/1999AprJun/0202.html
   
  > Of course, background is deprecated (cf
  > http://www.w3.org/TR/html4/struct/global.html#edef-BODY ) but that doesn't
  > help us now.
  > 
  > Please tell me if I've missed something in the guidelines about this.  I
  > know its there in spirit, but I don't see a literal reference in 1.1, which
  > states
  > 
  > >For example, in HTML:
  > >         Use "alt" for the IMG, INPUT, and APPLET elements, or provide a
  > > text equivalent in the content of the OBJECT
  > >         and APPLET elements.
  > >         For complex content (e.g., a chart) where the "alt" text does not
  > > provide a complete text equivalent, provide an
  > >         additional description using, for example, "longdesc" with IMG or
  > > FRAME, a link inside an OBJECT element, or a
  > >         description link.
  > >         For image maps, either use the "alt" attribute with AREA, or use
  > > the MAP element with A elements (and other text)
  > >         as content.
  > 
  > Len
  > 
  > --
  > Leonard R. Kasday, Ph.D.
  > Institute on Disabilities/UAP, and
  > Department of Electrical Engineering
  > Temple University 423 Ritter Annex, Philadelphia, PA 19122
  > 
  > kasday@acm.org
  > http://astro.temple.edu/~kasday
  > 
  > (215) 204-2247 (voice)  (800) 750-7428 (TTY)
  > 
  > The WAVE web page accessibility evaluation assistant:
  > http://www.temple.edu/inst_disabilities/piat/wave/
  
  -- 
  Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
  Tel:                         +1 831 457-2842
  Cell:                        +1 917 450-8783
  

--
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 Thursday, 22 June 2000 02:15:14 GMT

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