[webvtt] Question about cue position and control interface

alastor0325 has just created a new issue for 
https://github.com/w3c/webvtt:

== Question about cue position and control interface ==
https://w3c.github.io/webvtt/#processing-model

> If the user agent is exposing a user interface for video, add to 
output one or more completely transparent positioned CSS block boxes 
that cover the same region as the user interface\.
> 
> If the last time these rules were run, the user agent was not 
exposing a user interface for video, but now it is, optionally let 
reset be true\. Otherwise, let reset be false\.

The definition about "exposing a user interface" in [1] is the 
controls attribute is set. However, this attribute can't reflect the 
displaying status of control interface.

In most browser, the video control interface would appear when the 
cursor is hovering up the video, and disappear after a while the 
cursor hovered out.

So, the questions are
(1) Does the "exposing a user interface" here means "displaying a user
 interface" instead of "controls=ture"?
(2) Does that means we should adjust the cue position every time when 
the displaying status of user interface changed? 
(3) If we adjust the cue position when the user interface displays, 
after the 
user interface disappear, should we adjust cue position again? or keep
 its original position?

For question2, here is a example,
http://people.mozilla.org/~alwu/WebVTT/vttExample.html
The cue would overlap with control interface in Chrome and Opera, but 
the cue would adjust its position in Safari to avoid overlapping.

Is Safari behavior correct?

Thanks!

[1] 
https://html.spec.whatwg.org/multipage/embedded-content.html#expose-a-user-interface-to-the-user

Please view or discuss this issue at 
https://github.com/w3c/webvtt/issues/294 using your GitHub account

Received on Friday, 27 May 2016 09:10:00 UTC