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Re: pixel font-sizing and WCAG 2.0

From: Loretta Guarino Reid <lorettaguarino@google.com>
Date: Mon, 20 Sep 2010 17:30:57 -0700
Message-ID: <AANLkTi=kb2BbwDBquewXZHVLemqhWeSAGmTLsg7ueduy@mail.gmail.com>
To: aurélien levy <aurelien.levy@temesis.com>
Cc: public-comments-wcag20@w3.org
On Mon, May 31, 2010 at 6:35 AM, aurélien levy
<aurelien.levy@temesis.com> wrote:
> Hi,
>
> I sought an official response about the prohibition (or not) of pixel
> font-sizing in wcag 2.0. (like with font-size: 12px in CSS)
> For now, IE still doesn't scale if we just speak about font size and not a
> zoom feature.
> As far as I know, I didn't see any failures prohibiting it, except for the
> F80 for form fields (F69 isn't applicable as if I use pixel the text didn't
> resize).
>
> In my opinion if your intend was to prohibiting pixel font sizes on a AAA
> level, in the 1.4.8 sufficient techniques there is two gaps :
> - a missing G142 like sufficient technique saying "Using a technology that
> has commonly-available user agents that support zoom and does not require
> the user to scroll horizontally to read a line of text" (like with the small
> screen rendering mode in Opera browser).
> - a failure saying "Failure of Success Criterion 1.4.8 due to using pixel
> for font sizes in CSS or a technology that has commonly-available user
> agents that support zoom that DO require the user to scroll horizontally to
> read a line of text
>
> if your intend was to prohibiting pixel font sizes on a AA level :
> - change the G142 techniques to "Using a technology that has user agents
> that support zoom" this way I can use this techniques only if I am on a
> environment where I can be 100% sure that every users have an user agents
> that support zoom
> - add a failure saying "Failure of Success Criterion 1.4.4 due to using
> pixel for font sizes in CSS and NOT using a technology that has user agents
> that support zoom" or "Failure of Success Criterion 1.4.4 when text do not
> resize when visually rendered text is resized up to 200%"
>
> if your intend wasn't to prohibiting pixel font sizes at all there is
> nothing to add but I need an official statement about that
>
> Best regards,
>
> Aurélien Levy
> ----
> Temesis

================================
Response from the Working Group
================================
The working group believes that it is desirable for designers to be
able to utilize available features of any markup or programming
language, but it is important to consider whether there is sufficient
accessibility support for the environment that the web page will be
accessed.

As with specific levels of accessibility support in assistive
technologies for different technologies, the working group does not
set firm criteria for how broad support for pixel-based sizing in user
agents is.

>From http://www.w3.org/TR/UNDERSTANDING-WCAG20/conformance.html:
The WCAG Working group and the W3C do not specify which or how much
support by assistive technologies there must be for a particular use
of a Web technology in order for it to be classified as accessibility
supported.

It is not the intention of the WCAG working group to prohibit the use
of pixels for sizing text as long as user agents and AT support this
use.

In general, we do not write Failure techniques for problems that are
strictly accessibility support issues.

Loretta Guarino Reid, WCAG WG Co-Chair
Gregg Vanderheiden, WCAG WG Co-Chair
Michael Cooper, WCAG WG Staff Contact
Received on Tuesday, 21 September 2010 00:31:29 UTC

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