RE: FW: Pointer target size

I think (testing my logical brain) that either we allow for spacing and get results where smaller targets can work, or we don't allow for spacing as such. The center to edge calculation is also throwing up an oddity.

To keep it simple and allow for spacing I'd suggest:
For each target, the horizontal and vertical non-overlapping  distance between the center of the target and the @@center of the other targets@@ is at least 24 CSS pixels, except when...

That's basically setting a minimum of 24px size, with a metric that that (I think) is more adaptable to irregular shapes.

Cheers,

-Alastair


-----Original Message-----
From: Patrick H. Lauke <splintered@gmail.com> 
Sent: 29 October 2020 21:58
To: Mobile a11y tf (public-mobile-a11y-tf@w3.org) <public-mobile-a11y-tf@w3.org>
Cc: Alastair Campbell <acampbell@nomensa.com>; AGWG Chairs <group-ag-chairs@w3.org>
Subject: Re: FW: Pointer target size

I commented on the document itself (in answer to the original "non-overlapping distance", but i think this would also be simpler/more understandable than this "closest edge / opposite side / nearest target contortion), but copying it here as well for reference:

what you're trying to say, but it needs a lot more words (because "non-overlapping distance" doesn't really seem to make sense) is that for each target, you're wanting a circle with radius 12px from the center of the target, and none of the circles for any of the targets are allowed to overlap.

also, while this sort of reasoning/basing it on the center of a target works ok for regular/rectangular shaped targets, it may not be applicable for irregular-shaped targets (thinking for instance polygons as part of an SVG, or image map areas, or similar)

P

On 29/10/2020 21:35, jake abma wrote:
> Sorry for the multiple mails, but distsnce need to be in there ..
> 
> For each edge of a target, the distance to the closest edge of the 
> nearest target on the opposite side is at least 24 CSS pixels, except when:
> 
> 
> Op do 29 okt. 2020 22:29 schreef jake abma <jake.abma@gmail.com
> <mailto:jake.abma@gmail.com>>:
> 
>     Here it is:
> 
> 
>     For each edge of a target, the closest edge of the nearest target on
>     the opposite side is at least 24 CSS pixels, except when:
> 
> 
>     Op do 29 okt. 2020 22:24 schreef jake abma <jake.abma@gmail.com
>     <mailto:jake.abma@gmail.com>>:
> 
>         If fact, what we're looking for is more like: each outer edge of
>         a target is at least 24 px separated from other targets on the
>         opposite side
> 
>         Op do 29 okt. 2020 22:14 schreef jake abma <jake.abma@gmail.com
>         <mailto:jake.abma@gmail.com>>:
> 
>             18px area I mean...
> 
>             Op do 29 okt. 2020 22:12 schreef jake abma
>             <jake.abma@gmail.com <mailto:jake.abma@gmail.com>>:
> 
>                 Small addition, even with this adjustment you'll en up
>                 with a 18px target, imagine the right one is 24, the
>                 left 12 with 6px spacing will pass
> 
>                 Op do 29 okt. 2020 21:37 schreef Sukriti Chadha
>                 <sukriti1408@gmail.com <mailto:sukriti1408@gmail.com>>:
> 
>                     Hi Alastair, Rachael, Chuck and MATF members,
> 
>                     In today's MATF meeting, we went over the latest
>                     proposed wording in this document
>                     <https://docs.google.com/document/d/1_EHFVE-p4jEtKFa2jMEUruSvu6iv-Vt7UxRW9SrHTCQ/edit>.
>                     Jake brought up a great point with an example. It
>                     had two adjacent targets of 12 px width with a 6 px
>                     spacing that would pass this criteria even though
>                     each would have only 18 px in total instead of the
>                     24 we are aiming for (a drawing is included in the
>                     doc). It would run into similar problems as the one
>                     before where smaller target sizes might be
>                     encouraged due to shared spacing. To avoid that we
>                     added "non-overlapping" to the distance.
> 
>                     Please let me know if I can help clarify. Thank you
>                     everyone for your patience with this!
> 
>                     Best,
>                     Sukriti
> 
>                     PS We also looked into going with a 24X24 version of
>                     2.5.5 (the AAA version) but considered elements such
>                     as side rail links that aren't part of sentences but
>                     standalone links which would fail the criteria on a
>                     large number of websites even though those are the
>                     only targets in a 24X24 area.
> 
> 
> 
>                     On Thu, Oct 22, 2020 at 11:24 AM Alastair Campbell
>                     <acampbell@nomensa.com
>                     <mailto:acampbell@nomensa.com>> wrote:
> 
>                         Sorry, I should have CCed the task force as
>                         well.____
> 
>                         __ __
> 
>                         __ __
> 
>                         *From:*Alastair Campbell
>                         *Sent:* 22 October 2020 15:53
>                         *To:* WCAG list ____
> 
>                         __ __
> 
>                         Hi everyone,____
> 
>                         __ __
> 
>                         We discussed pointer-target-spacing yesterday,
>                         and whilst there was a general wish to carry on
>                         with it, we needed a new version to account for
>                         some of the comments.____
> 
>                         __ __
> 
>                         I’ve gathered a couple of suggestions together
>                         to form this version:____
> 
>                         __ __
> 
>                         For each target, the horizontal and vertical
>                         distance between the center of the target and
>                         the closest edge of the nearest target is at
>                         least 12 CSS pixels except when:____
> 
>                           * *Inline*: The target is in a sentence or
>                             block of text;____
>                           * *User Agent Control:* The size of the target
>                             is determined by the user agent and is not
>                             modified by the author;____
>                           * *Essential*: A particular presentation of
>                             the target is essential to the information
>                             being conveyed.____
> 
>                         __ __
> 
>                         *Note*: The User Agent Control exception would
>                         not apply as soon as styling properties such as
>                         font size - and in the case of mobile/tablet
>                         browsers, viewport meta - has been modified by
>                         the author____
> 
>                         __ __
> 
>                         (Google doc version
>                         
> <https://docs.google.com/document/d/1_EHFVE-p4jEtKFa2jMEUruSvu6iv-Vt7U

> xRW9SrHTCQ/edit?usp=sharing>)____
> 
>                         __ __
> 
>                         Don’t panic about the “12px” bit, that is the
>                         same as 24px wide/tall but if you measure from
>                         the center then you half it. It was a suggestion
>                         from Jeff Witt in #1444
>                         <https://github.com/w3c/wcag/issues/1444> that
>                         should prevent the shared space aspect.____
> 
>                         __ __
> 
>                         CCing Wilco to make sure the testing perspective
>                         is considered for this approach. ____
> 
>                         __ __
> 
>                         There are other comments to deal with, but does
>                         this seem like a good basis to continue?____
> 
>                         __ __
> 
>                         Kind regards,____
> 
>                         __ __
> 
>                         -Alastair____
> 
>                         __ __
> 
>                         -- ____
> 
>                         __ __
> 
>                         @alastc / www.nomensa.com
>                         <http://www.nomensa.com>____
> 
>                         __ __
> 


--
Patrick H. Lauke

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Received on Friday, 30 October 2020 00:26:18 UTC