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Thread: SC 1.4.4: Failures and Sufficient Techniques

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From: Weissenberger, Todd M
Date: Mon, Apr 08 2019 8:44AM
Subject: SC 1.4.4: Failures and Sufficient Techniques
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According to the WCAG documentation, it appears that Page Zoom in common browsers is sufficient to for conformance with WCAG SC 1.4.4 where HTML/CSS documents are concerned. However, it's also understood that some content or function still might break at 200% magnification.

Understanding that conformance and accessibility are not the same (and taking into account the prevalence of mobile browsing) what's the current thinking on this? What's your best practice?

Regards,
Todd

T.M. Weissenberger
IT Accessibility Coordinator
Information Security and Policy Office
University of Iowa
319-384-3323

he/him/his

From: Steve Green
Date: Mon, Apr 08 2019 9:19AM
Subject: Re: SC 1.4.4: Failures and Sufficient Techniques
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For this particular success criterion, we test the appearance and behaviour in Internet Explorer 11, Firefox and Chrome at all zoom levels up to 200%. It is quite common for issues to occur in one browser and not the others, so you definitely cannot rely on testing only with one browser. And it's not always Internet Explorer that breaks - I have seen plenty of websites where Chrome and/or Firefox break but Internet Explorer doesn't (or it breaks in a different way).

It is not sufficient to only test at 100% and 200% zoom because we often see issues that occur only at intermediate zoom levels.

So far I have not seen anything to suggest it is worth testing this success criterion on mobile devices, although we do verify that pinch-to-zoom has not been turned off. However, I am certainly willing to review that decision if there is any evidence it's worth doing. Pinch to zoom does what you would expect - it makes everything larger - but that is not the case with zooming on desktop browsers. I am guessing that is because pinch-to-zoom works directly with the video card, whereas browser zoom is presumably done via the browser's rendering engine.

Steve Green
Managing Director
Test Partners Ltd


From: Patrick H. Lauke
Date: Mon, Apr 08 2019 9:23AM
Subject: Re: SC 1.4.4: Failures and Sufficient Techniques
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On 08/04/2019 16:19, Steve Green wrote:
> Pinch to zoom does what you would expect - it makes everything larger - but that is not the case with zooming on desktop browsers. I am guessing that is because pinch-to-zoom works directly with the video card, whereas browser zoom is presumably done via the browser's rendering engine.

Just on that point, the simpler answer is: on desktop, when zooming, the
browser reflows content (if the content is responsive/adapts to the
width of the window). On mobile/tablet, there's an additional viewport
that determines the "logical" width of content, and any zooming that
happens with pinch-to-zoom then zooms into that without any additional
reflow.

P
--
Patrick H. Lauke

www.splintered.co.uk | https://github.com/patrickhlauke
http://flickr.com/photos/redux/ | http://redux.deviantart.com
twitter: @patrick_h_lauke | skype: patrick_h_lauke

From: Patrick H. Lauke
Date: Mon, Apr 08 2019 9:29AM
Subject: Re: SC 1.4.4: Failures and Sufficient Techniques
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On 08/04/2019 15:44, Weissenberger, Todd M wrote:
> According to the WCAG documentation, it appears that Page Zoom in common browsers is sufficient to for conformance with WCAG SC 1.4.4 where HTML/CSS documents are concerned. However, it's also understood that some content or function still might break at 200% magnification. > Understanding that conformance and accessibility are not the same
(and taking into account the prevalence of mobile browsing) what's the
current thinking on this? What's your best practice?

Just because full page zoom is now the most common/prevalent
functionality available in browsers, it doesn't mean it's now an
automatic pass of 1.4.4 (your first sentence seems to suggest that's
what you're thinking?)

You still need to test that zooming (and in particular on desktop,
zooming with its potential for reflow/relayout in the browser,
particularly when the browser window itself is relatively small) doesn't
cause any issues.

If content/fuctionality breaks when using full-page magnification up to
200%, then that's a failure of 1.4.4.

Generally, things like sticky headers/footers, absolutely positioned
elements, and elements with overflow:hidden / suppressed scrolling are
the main culprits when it comes to failures of 1.4.4, even with full
page zoom.

P
--
Patrick H. Lauke

www.splintered.co.uk | https://github.com/patrickhlauke
http://flickr.com/photos/redux/ | http://redux.deviantart.com
twitter: @patrick_h_lauke | skype: patrick_h_lauke