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Re: Prohibiting authors from disabling Pinch Zoom as failure for Reflow 1.4.10

From: Luis Garcia <w3c@garcialo.com>
Date: Tue, 29 Jan 2019 12:18:58 -0800
Message-ID: <CACRwngSNDQxF2=Zb=0BUaj+7qsmOzZBvMQrKKsy1mX2U-qTEBg@mail.gmail.com>
To: Shawn Lauriat <lauriat@google.com>
Cc: Silver TF <public-silver@w3.org>
If you use a user agent that ensures you can zoom, then it doesn't create a
barrier for you...while you're using that user agent. And while one user
agent having that ability implies that you could have it in another user
agent, it doesn't guarantee that you would (or even should) have it in
another user agent. While the barrier wouldn't exist for you, it would
still exist either until that functionality became guaranteed in all user
agents or the web page that disabled zooming stopped disabling it.

I would say, it's still a failure and that the responsibility is with the
site developer.

Perhaps in the same way that we would provide a method for ensuring a
contrast minimum for text, we could provide a method for ensuring zoomable

"Ensure that users can always zoom the page" and then gives guidance for
how to avoid building a page that creates this barrier.

As an aside, the methods I've seen for disabling zooming has typically been
done via <meta name="viewport"...> elements with user-scalable="no" or some
value set for maximum-scale.


On Tue, Jan 29, 2019 at 9:13 AM Shawn Lauriat <lauriat@google.com> wrote:

> Forwarding a question from Josh on the main working group list that I'd
> like to expand on, given the conversation we had around conformance and
> user agent requirements.
> Flipping the question of how to express usability failure in terms of user
> agent / assistive tech / platform gaps around to the other case: currently,
> Chrome (Android) offers a setting to enable the user to remove the ability
> of a site to disable pinch zoom (Settings > Accessibility > Force enable
> zoom), but Chrome for iOS doesn't offer this (that I can find, at least).
> If I use a user agent that ensures I can zoom no matter what the content
> specifies, implying other user agents could very well offer the same
> feature, does this still constitute a failure? Does that failure's
> responsibility sit with the user agent or the CSS of the site?
> Given our current direction of only having methods and not having "Failure
> techniques", I think this example would pass, as the user has ways to still
> zoom as needed, given that a cognitive walkthrough would take into account
> the user agent ability to override the zoom behavior of the site (just like
> user stylesheets can override site CSS).
> What do you think?
> -Shawn
> On Tue, Jan 29, 2019 at 9:26 AM Joshue O Connor - InterAccess <
> josh@interaccess.ie> wrote:
>> Hi,
>> In the failures section there are 'draft' failures listed. This one with
>> health warnings.
>>    - @@ "Interfering with a user agent's ability to zoom" i.e., author
>>    using: maximum-scale or minimum-scale or user-scalable=no or
>>    user-scalable=0 in the meta element ?? @@ Note: In Pinch zoom thread
>>    on the WCAG list
>>    <https://lists.w3.org/Archives/Public/w3c-wai-gl/2016AprJun/0502.html>
>>     people did not seem to be in favor of this as a failure.
>> While it would make a tidy failure if we could say - 'do not disable
>> pinch zoom'. If that's not a runner it should be removed as a failure as
>> its currently confusing to see it there. I see Jon and Patricks comments
>> after David posed the question.
>> Any good reason for keeping it?
>> Thanks
>> --
>> Joshue O Connor
>> Director | InterAccess.ie
Received on Tuesday, 29 January 2019 20:19:32 UTC

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