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Re: Accessibility Features in SVG - Image Scaling

From: Charles McCathieNevile <charles@w3.org>
Date: Fri, 21 Jul 2000 00:21:46 -0400 (EDT)
To: Dave J Woolley <DJW@bts.co.uk>
cc: "'w3c-wai-ig@w3.org'" <w3c-wai-ig@w3.org>
Message-ID: <Pine.LNX.4.20.0007210016210.19827-100000@tux.w3.org>

I take your point about the heavy pixellation being a possible benefit for
some users. Further in the document we actually show a stylesheet that is
designed to give a similar effect - emphasise the outlines of an image.

Some SVG images can be bloated, but in the examples I have played with they
are generally comparable in size to raster formats (which are normally

Thanks for the comments - please keep them coming <grin/>



On Mon, 17 Jul 2000, Dave  J Woolley wrote:

  I'm going to comment on this document in several parts....
  The case for image scaling being a benefit is flawed.
  A larger image in itself will improve readability, but
  not because of greater detail, but rather because it allows
  someone with poor eyesight to see the same level of detail
  as someone with good vision would see on a smaller image.
  In fact, if I look at figure 1.1 without my glasses, the
  pixellated image is easier to see than the detailed image,
  because the pixellation results in heavy black outlines.
  Image scaling can improve readability of technical diagrams
  for all users.
  In principle, vector formats can reduce the volume of 
  transmitted data and therefore improve accessibility to
  people who can't afford high bandwidth connections, however,
  there have been requests for data compression on the SVG
  list, suggesting that real life SVG is fairly bloated.

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 Friday, 21 July 2000 00:21:49 UTC

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