Re: Testability of Animation from interactions Issue 18

On 11/01/2017 16:35, Gregg C Vanderheiden wrote:

> I agree that rewording the animation SC to "1/3 of the viewport”
> rather than referring to web page is better.    You will still need
> to make assumptions about screen size, resolution, and viewing
> distance.

As physical (i'm assuming you mean physical?) screen size, pixel density 
(assuming that's what you mean by resolution, i.e. the dpi/dppx) and 
viewing distance are all variables that are essentially 
unknown/impossible to detect for authors, and impossible for testers to 
cater for all possible variations, I'm assuming it's ok to make those 

> We started with the language direct from research.

Likely the research had some standardised measurements etc that it was 
anchored on (a particular screen size, a user sitting X feet in front of 
the screen, etc)? In that case, the direct applicability of those 
measures to a fundamentally variable scenario of potentially infinite 
variations of physical screen size, viewing distance, etc is 
questionable I'd say.

> We then
> translated it into language that were meaningful (pixels) (see Note
> 1) — but no matter what you translate it into - it is impossible to
> evaluate a screen manually and you must use a tool of some sort.  So
> we made sure such a tool was available and free. [Note: since Trace
> moved from University of Wisconsin-Madison to University of Maryland,
> College Park the update on the tool broke.   We are in the process of
> fixing that. ]

Does the tool require you to enter the variables like physical screen 
size, viewing distance, etc? Or does it simply base its calculation on 
the screen/window size? If the latter, then it's doing nothing different 
from what I'm proposing, i.e. anchoring any measurement on 
viewport/screen size and writing out clearly what that ratio is.

>>>> Does "visual field on the screen" not, in essence, mean the
>>>> full size of the screen/viewport?
> RE viewport — no     "visual field on the screen”   does not mean the
> same thing as Viewport    since what the sentence says is "10 degree
> visual field on the screen”    and so the visual field in that case
> in only a 10 degree visual angle portion of the viewport.

So the answer is actually yes? i.e. "visual field on the screen" as a 
whole means the whole size of the viewport, and then of that you 
calculate a 10 degree angle portion? If so, then it is possible to 
rewrite the "10 degree visual field on the screen" into some 
relationship that's anchored on the size of the viewport?

>>>> And if not, isn't the general flash/red flash definition not
>>>> also fundamentally flawed as it can't take into account
>>>> physical screen size / viewing distance / etc, regardless of
>>>> the existence of a "tool"?
> Not flawed.  But it is subject to the same problems you are talking
> about with this SC.   If you read the rest of the text  of the
> glossary definition you will see we addressed them by assuming screen
> size, resolution, and viewing distance.  Since (in this case) we are
> talking about things being a problem if they are large— our
> assumptions were based on typical to older screens — with newer
> screens creating less of a problem.  So viewing the material on a
> higher resolution screen or on a mobile device would alway be safer.

But a mobile device screen is usually held closer to the viewer's eye, 
which in essence means that it occupies the same/similar overall visual 
field of a user as a larger monitor that's further away, no?

> So our criteria resulted were based on research, were set to
> accommodate most common and older tech at the time, and still held
> (were safer) with newer and mobile screens.

I think this may need a rethink, or at least a different anchoring, to 
make it more generally relevant in a world where screens come in all 
shapes and sizes, resolutions, and typical viewing distances.

Patrick H. Lauke | |
twitter: @patrick_h_lauke | skype: patrick_h_lauke

Received on Wednesday, 11 January 2017 17:26:04 UTC