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RE: Web Forms: Usability and Accessibility Question.

From: Jon Hanna <jon@hackcraft.net>
Date: Thu, 5 Feb 2004 10:09:39 +0000
Message-ID: <1075975779.40221663b1275@>
To: "w3c-wai-ig@w3.org" <w3c-wai-ig@w3.org>

> > From: Samuel Rinnetmäki [mailto:w3wai@puoli.net]
> [snip]
> > You can use style sheets to allow the graphis to grow and 
> > shrink with the
> > text:
> >  img.asterisk { width: 0.5em; height: 0.5em;}
> > 
> > Is there a problem with that?
> The problem is that it's impossible (?) to set the "true" width/height
> of the image (i.e. its proper pixel size) via ems. So even
> on systems where the text has not been resized, the graphic can potentially
> look very oddly pixelated due to it being stretched/shrunk by uneven
> multiples/fractions...if that makes sense.
> Ideally, we'd have a vector image that scales cleanly no matter what. But
> I'm not sure SVG is up to the task yet (?)

SVG in and of itself would be, but even if all sighted your users have an SVG
plug-in the most browsers will only allow it in <object> elements not in <img>
elements. Support for the <object> element in many browsers is poor and so
while theoretically it has better mechanisms for alternative content than <img>
in practice it does not.

If you want to do resizing of images then one option is to send a image that has
a very large "natural" size, so that it is scaling down rather than scaling up,
in general this *sometimes* works quite well, but at the expense of a download
time that would be quite nasty for low-bandwidth users.

Jon Hanna
*Thought provoking quote goes here*
Received on Thursday, 5 February 2004 05:09:59 UTC

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