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Re: CFC: Target Size and Target Size (no exception) SC

From: Patrick H. Lauke <redux@splintered.co.uk>
Date: Wed, 24 May 2017 10:22:19 +0100
To: w3c-wai-gl@w3.org
Message-ID: <e5ced094-0d00-08d1-5f64-9b5a9e16a69c@splintered.co.uk>
On 24/05/2017 02:58, Gregg C Vanderheiden wrote:
> I still continue to have concerns about this.     40px is a non-defined 
> size.   on ever device it is a different size 
 > — yet we are saying it
 > MUST be this big or larger —  when  THIS   is some arbitrary size on
 > different screens.
 >

Note that it's not completely arbitrary, just the best that can 
currently be defined.
On devices/UAs where a CSS pixel approximately matches the definition of 
the reference pixel https://www.w3.org/TR/css3-values/#reference-pixel a 
size defined in CSS pixels shakes out to roughly (with varying degrees 
of "rough") the same size at the same viewing/use distance.

Indeed, on mobile/touch devices there's certainly variance, but a size 
defined in CSS pixels (when the ideal viewport is set on the page using 
the appropriate meta element) comes to roughly the same size as rendered 
on the screen. (regardless of whether it's a high-dpi/"retina" display 
or not, since we're talking CSS pixels and not actual physical pixels).

See 
https://www.w3.org/WAI/GL/mobile-a11y-tf/wiki/Summary_of_Research_on_Touch/Pointer_Target_Size#Comparison_of_web_content_sized_in_px_and_physical_size_of_rendered_content_on_common_device_screens

[...]
> Finally — why do controls need to be large for everyone when a person 
> who needs them to be larger can zoom to make them larger — as large as 
> they need them to be.

Why do websites need to define a specific minimum color contrast when 
users can just use high contrast mode on their device?

Zooming (in most/all user agents on phone/tablet devices) leads to 
horizontal and vertical scrolling. Yes, a user can zoom to make targets 
more easily "tap-able", but at the expense of then having to scroll in 
both directions around the page.

Having said all that, I'm still personally leaning more towards turning 
this into a best practice piece of advice (in Silver), rather than a 
hard SC in WCAG 2.1.

P
-- 
Patrick H. Lauke

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Received on Wednesday, 24 May 2017 09:22:51 UTC

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