Re: [presentation-api] Allow page to designate a default presentation URL

I also wanted to summarize the use cases and requirements and thoughts
 that led to the proposal above.

## Use cases

1. the user interacts with the present button in user agent’s 
interface (or causes the browser to start a presentation in some other
 way, e.g. by tapping with the phone on an NFC pairing tag), the page 
overrides browser’s default behavior and starts a presentation on the 
device selected by the user (or joins an existing remote presentation 
if it’s already running on the selected device).
2. the user agent is already connected to a second screen (i.e is 
mirroring the same tab to the screen), the page chooses at some point 
to provide its own content to present on the screen instead of the 
default behavior
3. the user interacts with the present button in user agent’s 
interface, the user agents mirrors the page to the selected screen 
since the page chose not to override user agent’s behavior
the user wants to mirror page without allowing it to override the user
 agent’s behavior, it should be possible

## Requirements

1. the page should be able to gain control over the browser initiated 
presentation
2. the page should be able to provide a different presentation URL 
each time when the page wants to override the default behavior (use 
cases 1 and 2).
3. the page should be able to join an existing presentation instead of
 starting a new one
in the use case 1 the list of the screens shown by the user agent to 
the user should be consistent with the list shown if the user triggers
 the presentation from the page
4. the user agent should show only mirroring capable screens if the 
page doesn’t want to override the default behavior
5. the page should be able to choose whether to override the default 
behavior (mirroring) or provide the presentation url to use by the 
user agent when user interacts with the user agent’s interface
6. the user agent’s interface shouldn’t be available if there’s no 
screen capable of presenting the page’s content if it overriden the 
default mirroring behavior
7. user should be able to choose whether to let the page override the 
default mirroring behavior or not

## Implications

1. Requirement 1 implies an event (Promise wouldn’t really work 
because it could hang forever and never resolve) that would provide an
 initiated PresentationSession to the page
2. Requirement 2 implies a special property, method or a DOM element 
(i.e. link or meta) for specifying the presentation URL to use for the
 browser initiated presentation
3. Requirement 3 implies the user agent should allow the user to pick 
screens that have a presentation running
4. Requirement 4 implies the same URL should be specified for the 
default presentation and when starting a new session by the page; 
ideally it should be specified in one place
5. Requirements 5 and 6 imply that there should be a way for the page 
to opt in to overrided the behavior (or alternatively opt out)
6. Requirement 7 implies that the default presentation URL should be 
set before the event is sent to the user agent
7. Requirement 8 is satisfied through some website or generic setting 
that would disable any related events for the origin.


-- 
GitHub Notif of comment by avayvod
See 
https://github.com/w3c/presentation-api/issues/26#issuecomment-118028520

Received on Thursday, 2 July 2015 13:15:23 UTC