Re: Testability of Animation from interactions Issue 18

On 10/01/2017 22:55, Gregg C Vanderheiden wrote:

> 2) I agree with Patrick that 10 degrees of visual field won’t work
>
>  1. you can’t calculate that unless you know  a) how far the person is
>     from the screen   b) the size of the screen  and c) the pixel
>     resolution of the screen d) the scaling of the screen.   None of
>     these are known to the author and change from user to user
>  2. (Most people couldn’t calculate it if they did know those things)

Related to this, is there any chance the definition "general flash and 
red flash thresholds" currently in WCAG 2.0 can also be somehow 
changed/simplified for 2.1 according to whatever is decided here, as it 
presents exactly the same problems?

> 3) You can’t use 1/3 of web page because
>
>  1. a web page could be 500 ‘pages’ long so nothing would be 1/3 of it.
>  2. and you can’t use 1/3 of screen for the same reason as #2 above.
>
>
> 4)  I THINK — Doing it in CSS pixels (aka David) is the best bet but
> remember that a large blinking “O" only changes a relatively small
> number of pixels -- so you might look at pixel area rather than pixels.

What about simply percentage of overall screen/viewport size? It's still 
an approximation, as some users will be closer/further away from their 
screen so even the full screen/viewport will in fact occupy different 
angle of their full field of view, but it's at least something that can 
be consistently queried and tested (though in context of responsive 
design, it'll need to be tested for each breakpoint/common device screen 
resolution). for instance, simply saying "more than 1/4 of the viewport" 
or similar?

> 5) I wouldn't ban it - but rather ban anything the has a duration longer
> than say  three seconds that can’t be stopped.   Such animations are
> very useful for directing attention for people with cognitive
> disabilities.   Also important sometimes for warnings.

Agree in part, though certain very extreme animations, even if shorter 
than 3 seconds, may cause issues for certain user groups (e.g. vertigo / 
motion sensitivity)

P
-- 
Patrick H. Lauke

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Received on Tuesday, 10 January 2017 23:05:18 UTC