Re: Mobile needs a question answered

Found an article
Lindberg, T., Näsänen, R.: The effect of icon spacing and size on the speed
of icon processing in the human visual system. Displays 24(3), 111–120
(2003)
 For small number of icons the inter-element spacing for icons should be
more than 1/2 icon, for large number of icons, small icon spacing 1/4-1/2
icon is recommended

On Wed, Jan 30, 2019 at 4:14 PM Jim Allan <jimallan@tsbvi.edu> wrote:

> Alastair
> thoughts inline
>
> On Wed, Jan 30, 2019 at 12:36 PM Alastair Campbell <acampbell@nomensa.com>
> wrote:
>
>> 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.
>>
>
> Exactly. This is the point the Mobiles question.
> How many pixels in between 2 active elements on a screen meets user need
> on the low-vision side?
> currently, Mobile TF have that spacing at two pixels.
> hmm, rereading all of this again...
> yes, spacing between center of targets is important, and seem to be the
> prevailing heuristic used by OS to determine target activation.
> visual separation is also an issue for differentiation of targets. the
> google/android spec for mobile says 8dp between targets
> of note is a study I found using older adults (65-95 in age) using Spacing
>  between  targets  ... 5  levels:  0  mm,  3.5  mm,   7   mm,   and 10.5
> mm,   plus   an   additional   level   for   non-­‐adjacent   targets   (a
>   single   target  with  no  neighbors). "
> Surprisingly "... spacing  between  targets  did  not  show  significant
>  effects  in  either  of  the  tasks"  (tapping or swiping different
> targets). [1]
> BBC says 1px of inactive space between targets (
> https://www.bbc.co.uk/guidelines/futuremedia/accessibility/mobile/design/spacing
> )
>
> So we have (changed all measurements to device pixels - dp)
> MATF proposing 2dp
> BBC says minimum of 1dp
> android says 8dp
> and a study saying spacing is not an issue.
> seems the answer may be somewhere between 0-8 non-collapsible space.
>
> perhaps we can talk more on the LVTF call tomorrow.
>
>
> 1.
> https://webcache.googleusercontent.com/search?q=cache:m7xl4zoWoVkJ:https://hillside.net/plop/2012/papers/Group%25201%2520-%2520Elk/Target%2520and%2520Spacing%2520Sizes%2520for%2520Smartphone%2520User%2520interfaces%2520for%2520Older%2520Adults%2520-%2520Design%2520patterns%2520Based%2520on%2520an%2520Evaluation%2520with%2520Users.pdf+&cd=11&hl=en&ct=clnk&gl=us
> a different paper that cited the results of the paper above - with charts
> http://eprints.maynoothuniversity.ie/6621/1/PAS_user%20interface%202015.pdf
> and a book "Creating Mobile Gesture-based Interaction Design Patterns for
> Older Adults: a study of tap and swipe gestures with Portuguese seniors" -
> https://repositorio-aberto.up.pt/bitstream/10216/64972/2/27603.pdf
>
> Jim
>
>>
>>
>> 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.
>>
> It has been difficult to find research on visual separation of adjacent
> items.
>
>>
>>
>> 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/
>> <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> 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>
>> 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>
>> *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
>>
>> Chief Accessibility Officer
>>
>> *Level Access*
>>
>> jon.avila@levelaccess.com
>>
>> 703.637.8957 office
>>
>>
>>
>> Visit us online:
>>
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>>
>>
>>
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>>
>>
>>
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>>
>>
>>
>> *From:* Wayne Dick <wayneedick@gmail.com>
>> *Sent:* Tuesday, January 29, 2019 5:24 PM
>> *To:* Jim Allan <jimallan@tsbvi.edu>
>> *Cc:* public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>
>> *Subject:* Re: Mobile needs a question answered
>>
>>
>>
>> *CAUTION:* This email originated from outside of the organization. Do
>> not click links or open attachments unless you recognize the sender and
>> know the content is safe.
>>
>>
>>
>> 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> 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
>>
>
>
> --
> 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