Re: add "orientation" to Widgets: P&C

On 20 Jun 2012, at 08:55, Tobie Langel wrote:

> On 6/20/12 8:34 AM, "Scott Wilson" <scott.bradley.wilson@gmail.com> wrote:
> 
>> Expressing a preferred starting orientation is a common use case for web
>> apps; the Mozilla proposal includes this[1], as does the PhoneGap
>> implementation of Widgets:P&C (using Preferences)[2].
> 
> This is also something the Coremob CG feels strongly about. Being able
> express a preference for a given orientation is critical for building
> HTML5 games on mobile devices.
> 
>> Outside of mobile, we also have a use case for portal applications built
>> with Apache Rave, where we may want to place a widget into a page region
>> depending on whether it would better suit a wide or narrow region in the
>> layout.
>> 
>> Orientation also already exists as a Media Feature[3]; there are two
>> valid values of the orientation media feature, 'portrait' and 'landscape':
>> 
>> "The Œorientation¹ media feature is Œportrait¹ when the value of the
>> Œheight¹ media feature is greater than or equal to the value of the
>> Œwidth¹ media feature. Otherwise Œorientation¹ is Œlandscape¹."
>> 
>> PhoneGap also has "default", however this doesn't actually mean "default"
>> but " enable both":
>> 
>> "please note that default means both landscape and portrait are enabled.
>> If you want to use each platform's default settings (usually
>> portrait-only), just remove this tag from your config.xml"
>> 
>> So orientation can refer to either or both of the preferred starting
>> orientation of the web app, and the orientations enabled for the web app.
> 
> Worth looking at the work going on in [Device Adaptation]. I like auto
> much more than "both" + "default" which is extremely confusing for authors
> and the end users alike.

Right, I think PhoneGap used "default" to mean "use this sensible default rather than the inconsistent defaults of the device platform".

Auto works better for me.

> 
>> I suggest an orientation property with the following semantics:
>> 
>> orientation = "portrait" // enable portrait only
>> orientation = "landscape" // enable landscape only
>> orientation = "portrait landscape" // enable both, start in portrait by
>> default
>> orientation = "landscape portrait" // enable both, start in landscape by
>> default
>> orientation = "both" // enable both portrait and landscape orientation,
>> start in current user agent orientation
>> [no value] // use user agent defaults
> 
> Needing to mix app life-cycle into this calls for finer-grained control,
> i.e. being able to modify this setting on a document level (via Device
> Adaptation?) or via scripting (using Mozilla's [Screen Orientation]?).
> 
> So this is either indicative of a mistake in the level at which the
> feature is being added or a scope creep.
> 
> That said, I think your proposal misses an important use case: enabling
> locking the orientation of games.

Good point - and this UC definitely requires control within applications as you say, whether at document or scripting level, rather than declaratively.

> 
> Typically, this is necessary not only because a given game is playable in
> portrait mode only, but also because auto-rotation of the device during
> the game would ruin the game play. That's why it is important for games to
> be also able to prevent auto-rotation.
> 
> Should that be expressed through more precise params inspired from
> Mozilla's proposal: portrait, landscape, portrait-primary,
> portrait-secondary, landscape-primary, landscape-secondary, auto? Should
> there be a different setting (prevent-autorotation) for that use case? I'm
> not sure.
> 
>> This could be added to Widgets:P&C as an attribute of the widget element;
>> this would also need to be harmonized in the mozilla proposal.
>> Alternatively, this could be developed as a standalone spec usable by
>> both, a bit like VMMF[4].
> 
> Where this ends up happening has a lot to do with how fine-grained it
> needs to be. Think we need use cases here.

OK, for now I'll pop a strawman draft up on github to have something to point at.

> 
> --tobie
> 
> ---
> [Device Adaptation]: http://dev.w3.org/csswg/css-device-adapt/#orientation
> [Screen Orientation]:
> http://dvcs.w3.org/hg/screen-orientation/raw-file/tip/Overview.html
>

Received on Wednesday, 20 June 2012 09:38:10 UTC