RE: let's bump to 10mm from 9mm

>> I like CSS pixels as a Sufficient technique, but if that's the SC wording then:
>> (1) it rules out other approaches (e.g. just using <button> and letting the UA do the sizing) and

>Well yes...as the default size that a UA decides to give to a <button>
>or similar may not be sufficient. So adding CSS to explicitly say button { width: 50px; height: 50px; }
> doesn't seem unreasonable to me.

It feels very strange to say that all things being equal (i.e. set to user-agent default), that using the <button> alone (with no CSS) could fail. So, based on some quick checks with how <button> is rendered in a few browsers I revise my earlier suggestion to:

2.5.4 Touch Target Size: Touch targets have a diameter of at least twice the height of capital letters in the user agent's default text size.

Then, all of the CSS unit measurements could then be techniques.  I know that the default height of buttons on mobile browsers can't be trusted to be 9mm, so this requirement is a lower bar than the original wording, but I'm just trying to find something that will work.
 

>> (2) it can cause problems with text resizing that wouldn't happen if a relative unit (e.g. em) was used.

>If authors are using measures other than CSS pixels, then they'd have to
>check the actual rendered size in pixels using devtools, or some
>calculation. This would be no different from things like "large text" in
>WCAG being oddly defined in points, requiring authors to work out what
>point size their text is (as they're either using px or em, for the most
>part).


> If the user has changed the default text size of their UA, would it not
conceptually fall under the same as "except when the user has reduced
the default scale of content" (the second part of the SC wording, as per
http://kwahlbin.github.io/Mobile-A11y-Extension/#touch-navigation)?

Agreed, I just meant that defining a size with pixels can cause the text inside the button to be cut-off when it is zoomed, causing problems for 1.4.4 Resize text.

Cheers,
Jan


(MR) JAN RICHARDS
PROJECT MANAGER
INCLUSIVE DESIGN RESEARCH CENTRE (IDRC)
OCAD UNIVERSITY

T 416 977 6000 x3957
F 416 977 9844
E jrichards@ocadu.ca

________________________________________
From: Patrick H. Lauke [redux@splintered.co.uk]
Sent: December-18-15 10:18 AM
To: Richards, Jan; public-mobile-a11y-tf@w3.org
Subject: Re: let's bump to 10mm from 9mm

On 18/12/2015 15:09, Richards, Jan wrote:
> I like CSS pixels as a Sufficient technique, but if that's the SC wording then:
> (1) it rules out other approaches (e.g. just using <button> and letting the UA do the sizing) and

Well yes...as the default size that a UA decides to give to a <button>
or similar may not be sufficient. So adding CSS to explicitly say

button { width: 50px; height: 50px; }

doesn't seem unreasonable to me.

> (2) it can cause problems with text resizing that wouldn't happen if a relative unit (e.g. em) was used.

If authors are using measures other than CSS pixels, then they'd have to
check the actual rendered size in pixels using devtools, or some
calculation. This would be no different from things like "large text" in
WCAG being oddly defined in points, requiring authors to work out what
point size their text is (as they're either using px or em, for the most
part).

If the user has changed the default text size of their UA, would it not
conceptually fall under the same as "except when the user has reduced
the default scale of content" (the second part of the SC wording, as per
http://kwahlbin.github.io/Mobile-A11y-Extension/#touch-navigation)?

P
--
Patrick H. Lauke

www.splintered.co.uk | https://github.com/patrickhlauke
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twitter: @patrick_h_lauke | skype: patrick_h_lauke

Received on Friday, 18 December 2015 17:10:11 UTC