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Re: Browser zooming sufficient for WCAG 1.4.4 (resize text)

for

From: Eades, Terri
Date: Jun 2, 2015 4:42PM

I think the "px vs. em" debate was born when responsive design was because fonts defined in px will NOT scale with the size the screen, therefore creating a usability problem because it can make reading difficult if your font is too big or too small for the screen you're on. It's not an accessibility issue in the traditional sense, but since good usability often results in better accessibility, I tend to lean on going with em's.


Terri Eades
Webmaster

Morgan Community College
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-----Original Message-----
From: Robert Fentress [mailto: <EMAIL REMOVED> ]
Sent: Tuesday, June 02, 2015 6:51 AM
To: WebAIM Discussion List
Subject: [WebAIM] Browser zooming sufficient for WCAG 1.4.4 (resize text)

I am confused as to the guidance given in the techniques for meeting or failing to meet WCAG success criteria 1.4.4 (resize text) <http://www.w3.org/TR/2008/REC-WCAG20-20081211/#visual-audio-contrast-scale>;.
I wonder if somebody could clarify best practice for me. While WCAG 1.0 seemed clear in its guidance forbidding font sizing with absolute units, WCAG 2 seems more vague, simply stating that text should be able to be resized 200% without loss of content or functionality.

What is unclear is whether the, now ubiquitous, browser page zoom functionality means that units like px are acceptable, since text whose size is defined this way will scale along with the entirety of the page.
If you just want to enlarge the text, independent of its containing elements, however, you will not be able to do so (at least with native
functionality) if absolute units are used. To me, relying on zoom capability to handle text resizing seems insufficient, because it often necessitates horizontal scrolling (a problem for my father who has low vision and boosts font size). That seems to be acceptable from the perspective of WCAG 2, though, since a sufficient technique for 1.4.4 is "G142:
Using a technology that has commonly-available user agents that support zoom <http://www.w3.org/TR/2014/NOTE-WCAG20-TECHS-20140916/G142>;". I've seen this discussed different places on the web, but people seem to have different perspectives on whether it is okay. WebAIM, at least, thinks "it is not vital that text sizes be defined in relative sizes."
<http://webaim.org/techniques/fonts/#font_size>;

What do you folks think?

Best,
Rob

--
Robert Fentress
Senior Accessibility Solutions Designer
540.231.1255

Technology-enhanced Learning & Online Strategies Assistive Technologies
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Blacksburg, Virginia 24061