W3C home > Mailing lists > Public > w3c-wai-gl@w3.org > April to June 2015

RE: Proposed mobile techniques for SC 3.2

From: Michael Pluke <Mike.Pluke@castle-consult.com>
Date: Fri, 10 Apr 2015 13:02:23 -0400
To: "WCAG (w3c-wai-gl@w3.org)" <w3c-wai-gl@w3.org>
Message-ID: <D3B76FCEBC826749AE4A1FB47BBD154612207E69@MAILR028.mail.lan>
Although this is being proposed for SC 3.2, it doesn't obviously seem to have much to do with the concept "Understandable" and has little similarity to the other items in 2.4 which all relate to ensuring that the underlying logic and behaviour are "predictable".

"Touch target" is not a defined term in WCAG, but a rough attempt could be something like "the region around a displayed control within which a touch event will operate that control". Because it is talking about the absolute size of a region on a physical user interface, there is clearly no parallel in WCAG (which relies on a user agent to render the content and to determine its absolute size).

Alastair's suggestion that it could be seen as being a gap in 2.4 makes a lot of sense to me. It's definitely related to touch controls being "operable" and is close to the concept of "navigable". But really it is quite different to the other SCs in 2.4 as they also relate to underlying logic and behaviour and not to physical user interface characteristics. I also agree with Alistair's suggestion that the first requirement is the most important.

When creating the European standard EN 301 549, we were unable to define requirements about target sizes that could be unambiguously applied across all types of ICT including mobile devices. If wording such as "adequate" and "large enough" is considered acceptable, then the proposed text certainly emphasises that a large enough target size is an important requirement.

Best regards,

Mike Pluke

From: Alastair Campbell [mailto:acampbell@nomensa.com]
Sent: 10 April 2015 09:32
To: WCAG (w3c-wai-gl@w3.org)
Subject: Re: Proposed mobile techniques for SC 3.2


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 17:02:58 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 16 January 2018 15:34:19 UTC