Re: Proposed new text for noaccess

On Tue, Oct 29, 2013 at 10:04 PM, Harald Alvestrand <harald@alvestrand.no>wrote:

> On 10/30/2013 01:14 AM, Mandyam, Giridhar wrote:
> > Referring back to Example 2 (
> http://www.w3.org/TR/mediacapture-streams/#examples), in existing
> implementations the permissions UI is presented as soon as the gUM call is
> made.
> >
> > If I'm to understand you correctly, the permissions call would instead
> only be presented when when applyConstraints() is invoked on the
> VideoStreamTrack to change "noaccess".
> >
> > So the user opens up the webpage and gets to see a camera preview image
> initially.  But the application is blocked from invoking
> canvas.getContext('2d').drawImage() or
> canvas.getContext('2d').getImageData() at this point because the "noaccess"
> constraint has not been changed.
> >
> > What other operations need to be blocked until the 'noaccess' constraint
> is modified?
>
> According to what Martin said earlier, the call to
> canvas.getContext(....) would not be blocked, it would simply render black.
>
>
> This is one point that's critical to clarify in the description of the
> constraint, if this is what we want; the current text EKR proposed reads
> as if the operation is not permitted, preventing the scenario above.
>

I could live with either, but I think Martin is probably right to suggest
black,

-Ekr



>
 >
> >
> > -----Original Message-----
> > From: Martin Thomson [mailto:martin.thomson@gmail.com]
> > Sent: Tuesday, October 29, 2013 4:53 PM
> > To: Mandyam, Giridhar
> > Cc: Harald Alvestrand; public-media-capture@w3.org
> > Subject: Re: Proposed new text for noaccess
> >
> > On 29 October 2013 16:48, Mandyam, Giridhar <mandyam@quicinc.com> wrote:
> >> Problem:  As far as I can tell, no permissions UI was ever presented to
> the user in the above scenario, because the "noaccess" constraint was never
> changed.  Is this the desired behavior?
> > This would be expressly prohibited.  Any pixel on the screen that is
> altered by the "noaccess" stream cannot be captured by the application.
>  The intent is that anything constrained as "noaccess" is inaccessible to
> applications.
>
>
> --
> Surveillance is pervasive. Go Dark.
>
>
>