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Re: Proposed mobile techniques for SC 3.2

From: Gregg Vanderheiden <gregg@raisingthefloor.org>
Date: Fri, 10 Apr 2015 16:06:09 -0500
Message-Id: <FB19D921-24B1-42EE-8716-889A6E1A7771@raisingthefloor.org>
To: GLWAI Guidelines WG org <w3c-wai-gl@w3.org>

I think this is important 

but I wonder about testability.   
And I’m not sure how we would determine what these mean.

This is for CONTENT — and target size is determined by they hardware.  
	e.g. the size of the button varies depending on whether it is displayed  on a    56 cm/23 inch  touch screen   or a 40cm/15.7in touchscreen   or a  10cm/4 inch screen

	In fact - what will fit on one screen would not on another 

If the author has no control over what size screen it would be on  —  how do they follow this provision?

If these are just  “SHOULD” guidelines (advisory) then these are fine.  I don’t see a problem/question.

but if they are SHALL  then … don’t they have to be measurable?    
— and don’t they need to apply  everywhere (all content)? 

We need to think about being on the receiving end of these.  If someone requires US to follow them - and will not pay our salary (fee) if we don’t. 
How will we know (and prove) that we have met them?

The question/concern is about about the Target Size/Spacing provision — but also for other ones as well.

Is this an advisory document (all "shoulds” )
or a conformance document  (you “Shall” do these or you don’t conform).
If it is ADVISORY 
    -  then the   “are” in the provision below needs to be changed to   “should”   or “is best if”  or something like that.

If it is a CONFORMANCE type document 
then we need to say exactly how large,   and say it in some measurable fashion that everyone would agree on whether it is met. 
 “large enough” is not measurable.     
“large enough to touch accurately”  is different for each person.  Which person is the “certified test measure person” ?
Ditto for “adequate"


Gregg Vanderheiden

> On Apr 10, 2015, at 3:32 AM, Alastair Campbell <acampbell@nomensa.com> wrote:
> 3.2 Touch Target Size and Spacing
> Providing adequate touch target size / Ensuring that touch targets are large enough to touch accurately without magnification
> Provide adequate spacing between touch targets
> AC: For these two, I think the first is far more important.  Using large targets is well established as helpful for everyone (Fiitt’s law), and whilst I can see having space between targets being helpful, it is much harder to do on smaller screens. (Thinking of the standard 'four buttons in a row' interface on many phone apps.)
> To me that indicates that the first should be sufficient, and the second advisory. However, in a world of many devices and relative pixels sizing, I’m not sure how you would define sufficient? I.e. How big is enough?
> In relation to success criteria, it isn’t clear from the TF note which WCAG2 SC these apply to, it points to there being a gap, probably under WCAG2 2.4?
> Kind regards,
> -Alastair
Received on Friday, 10 April 2015 21:06:43 UTC

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