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Re: SC failure for using pixel font size

From: Aurélien Levy <aurelien.levy@temesis.com>
Date: Thu, 17 Jul 2014 10:26:09 +0200
Message-ID: <53C788A1.2090800@temesis.com>
To: WCAG WG <w3c-wai-gl@w3.org>
Le 17/07/2014 09:26, Ramón Corominas a écrit :
> This is an interesting point. Since "accessibility supported" is 
> defined as "compatible with AT that users use", I think that SC 1.4.4 
> should take into account the reality that most low vision users who 
> rely on browser's zoom don't use the "full zoom" option, but text-only 
> increase.
> Of course we can argue that they could simply switch to use full zoom, 
> but this seems to be more a weak justification of a bad practice than 
> a real solution to the problem. The technology completely allows us to 
> achieve a good result with almost no effort and without forcing the 
> user to use a particular setting that creates a very bad usability.
> In any case, normally the use of absolute units is only problematic in 
> -some- containers and certain positioning properties, but not for the 
> text size.
> Regards,
> Ramón.
Even without using the zoom sufficient technique or another one listed 
as so, it's still not a failure in regard of the current failures we got 
except for text based form controls (F80). The F69 can't apply because 
it's about having content clipped, truncated or obscured when text is 
resized at 200% and in our case in browser not increasing pixel based 
font size we haven't that kinds of problems.

Furthermore as far a I know browser isn't considered as an AT and the SC 
text say "without assistive technology" so basically any user of AT is 
outside of the scope for this SC.

The only thing left is the intent of the 
SC http://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-scale.html 
that say :

"The scaling of content is primarily a user agent responsibility. User 
agents that satisfy UAAG 1.0 Checkpoint 4.1 
allow users to configure text scale. The author's responsibility is to 
create Web content that does not prevent the user agent from scaling the 
content effectively. Authors may satisfy this Success Criterion by 
verifying that content does not interfere with user agent support for 
resizing text, including text-based controls, or by providing direct 
support for resizing text or changing the layout. "


"If the author is using a technology whose user agents do not provide 
zoom support, the author is responsible to provide this type of 
functionality directly or to provide content that works with the type of 
functionality provided by the user agent. If the user agent doesn't 
provide zoom functionality but does let the the user change the text 
size, the author is responsible for ensuring that the content remains 
usable when the text is resized."

So, the real question I think WCAG must give an answer on is :
Is it a failure or not to use pixel font size in an environment where :
- user may have a browser that doesn't scale it and don't provide a zoom 
feature (IE6 for example + I'm not sure every mobile browser out there 
do it )
- no others sufficient technique is used


Aurélien Levy

Aurélien Levy
Received on Thursday, 17 July 2014 08:26:33 UTC

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