RE: Mobile needs a question answered

Sorry, I missed Jim’s email before responding to an LVTF one, this is the updated, full version!

I’ll try sifting through some of those links, but there is a basic question that was raised during the 2.1 discussions:
Is it better to have medium buttons spaced apart, or large buttons closely spaced?

E.g. imagine 6 buttons across the bottom of a 320px wide screen.

Is it better to have:

  *   6 buttons at 53px wide and no margin between them, or
  *   6 buttons at 44px wide and ~11px margin between them?

The centre of each button could be the same distance apart, but which is easier?

Do the phone OS heuristics make a difference to which is better, or nullify the difference? Does the heuristic enable you to miss small targets, but as long as there isn’t another target in the area it activates anyway? (That’s my experience.)

The upshot could be that the guideline needs to be about spacing between the centre of targets, not how large they are.

That also impacts how it aligns with low-vision issues, as you could differentiate buttons with spacing more easily than ones which are right next to each other.

Cheers,

-Alastair


From: Jim Allan <jimallan@tsbvi.edu>
Sent: 30 January 2019 15:47
To: Wayne Dick <wayneedick@gmail.com>; MATF <public-mobile-a11y-tf@w3.org>
Cc: Alastair Campbell <acampbell@nomensa.com>; Jonathan Avila <jon.avila@levelaccess.com>; public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>
Subject: Re: Mobile needs a question answered

Alastair,
As the question originally came from the Mobile group, I am looping them into the conversation. Perhaps they can add comments.

Based on several articles - seems 8dp is a reasonable spacing.

"Touch targets should also be spaced about 8 pixels apart, both horizontally and vertically, so that a user's finger pressing on one tap target does not inadvertently touch another tap target."
https://developers.google.com/web/fundamentals/accessibility/accessible-styles


"To balance information density and usability, touch targets should be at least 48 x 48 dp with at least 8dp of space between them." - https://material.io/design/layout/spacing-methods.html#touch-click-targets


https://medium.com/@zacdicko/size-matters-accessibility-and-touch-targets-56e942adc0cc


one caveat - the articles all point back to google/android specs. Most other articles related to target spacing are vague ("reasonable space", "a good amount of space", etc.) and are not helpful.

other Related stuff I found while searching for target spacing.
an old article with lots of research
https://www.uxmatters.com/mt/archives/2013/03/common-misconceptions-about-touch.php


<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726769/>
Reading Digital with Low Vision - NCBI - NIH<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726769/>


<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726769/>
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726769/


http://www.4ourth.com/Touch/


On Wed, Jan 30, 2019 at 8:47 AM Wayne Dick <wayneedick@gmail.com<mailto:wayneedick@gmail.com>> wrote:
Hi Alastair,
It kind of reduces to the same thing. It easy to miss a target you cannot separate from another. I'm a little embarrassed to admit how many times I hit the wrong target.
Wayne

On Wed, Jan 30, 2019 at 12:41 AM Alastair Campbell <acampbell@nomensa.com<mailto:acampbell@nomensa.com>> wrote:
Hi Jim,

Was that for seeing things, or hitting the targets?

Those seem like different problems, especially as the touch-screen OSs have heuristics so that if you tap between two targets, it guesses which you meant...

-Alastair

Apologies for typos, sent from a mobile.

________________________________
From: Jonathan Avila <jon.avila@levelaccess.com<mailto:jon.avila@levelaccess.com>>
Sent: Tuesday, January 29, 2019 11:45 pm
To: Wayne Dick; Jim Allan
Cc: public-low-vision-a11y-tf
Subject: RE: Mobile needs a question answered

HI Wayne, I also think that people with low vision might need more space because touch might not be as precise given that a person may be holding the device closer to their face and not have the same perspective as distance.  Also scotomas may also impact touch target accuracy for some users.

Jonathan

Jonathan Avila, CPWA
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From: Wayne Dick <wayneedick@gmail.com<mailto:wayneedick@gmail.com>>
Sent: Tuesday, January 29, 2019 5:24 PM
To: Jim Allan <jimallan@tsbvi.edu<mailto:jimallan@tsbvi.edu>>
Cc: public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org<mailto:public-low-vision-a11y-tf@w3.org>>
Subject: Re: Mobile needs a question answered

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Hi All,
Well all zoomed pixels are large, but that is only so that we can see them. So, I would assume that it takes 2-pixels for full sighted readers to separate things, it would take us 2 big pixels to distinguish things.

Wayne

On Tue, Jan 29, 2019 at 1:47 PM Jim Allan <jimallan@tsbvi.edu<mailto:jimallan@tsbvi.edu>> wrote:
How many pixels in between 2 active elements on a screen meets user need on the low-vision side? Mobile TF have it at two pixels.
And does the overall target size impact the spacing between elements requirement?
Anybody have any ideas or research?



--
Jim Allan, Accessibility Coordinator
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9452 http://www.tsbvi.edu/

"We shape our tools and thereafter our tools shape us." McLuhan, 1964


--
Jim Allan, Accessibility Coordinator
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9452 http://www.tsbvi.edu/

"We shape our tools and thereafter our tools shape us." McLuhan, 1964