Re: Testability of Animation from interactions Issue 18

Hi Patrick


RE Animation SC

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.   Do we have any research showing what size animation is a problem?   My understanding / experience is that even a very small animation can be ‘riveting’ to someone.    Is there  a sweet spot ? or is any animation a problem.  I think 1/3 of viewport is way too big.   I think animations much smaller are a problem.    BUT - viewport is the right track rather than web page if you are going to do size.   again you need to assume size,res,dist. 


RE Photosensitive Epilepsy SC

No I wouldn't agree that the Photosensitive Epilepsy SC should be reworded.   
 
We started with the language direct from research.  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 "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.   

 
>>>  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.     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. 



g


Gregg C Vanderheiden
greggvan@umd.edu



> On Jan 11, 2017, at 4:08 AM, Patrick H. Lauke <redux@splintered.co.uk> wrote:
> 
> On 11/01/2017 05:04, Gregg C Vanderheiden wrote:
>> 
>> 
>>> On Jan 10, 2017, at 6:46 PM, Patrick H. Lauke
>>> <redux@splintered.co.uk> wrote:
>>> 
>>> I'm failing to see why the "33% of any 10 degree visual field on
>>> the screen" has the issues (1 and 2) you noted, but the existing
>>> ".006 steradians within any 10 degree visual field on the screen
>>> (25% of any 10 degree visual field on the screen) " from WCAG 2.0's
>>> current definition for general flash and red flash thresholds
>>> doesn't?
>>> 
>>> Does "visual field on the screen" not, in essence, mean the full
>>> size of the screen/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"?
>> 
>> Hi Patrick
>> 
>> I said that it DID have the same problems — and worse. But there was
>> a tool that did the measurement automatically — so no one had to
>> figure out the bits.
> 
> So you'd agree that rephrasing both the general flash and red flash measurement in WCAG 2.0 and the proposed animation measures as something more in the format "1/3 of the viewport" (or whatever the most appropriate fraction of the visible viewport works best / approximates the existing "25% of any 10 degree visual field on the screen") or similar would be possible? Doing that would demystify the baffling measurement. If there's then also a tool that helps with the calculations, even better, but it would make the measurement as written in the spec a lot less obscure.
> 
>> And I suggested you might look at that approach here too.   And gave
>> other advice that related to the flash work.   Read my comments
>> again.  Maybe I didnt write them clearly enough.
> 
> I think I initially talked across purposes https://lists.w3.org/Archives/Public/w3c-wai-gl/2017JanMar/0160.html ... apologies.
> 
> P
> -- 
> Patrick H. Lauke
> 
> www.splintered.co.uk | https://github.com/patrickhlauke
> http://flickr.com/photos/redux/ | http://redux.deviantart.com
> twitter: @patrick_h_lauke | skype: patrick_h_lauke

Received on Wednesday, 11 January 2017 16:36:30 UTC