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RE: [mediaqueries] New requirements for media queries from Second Screen WG

From: Hyojin Song <hyojin22.song@lge.com>
Date: Wed, 2 Dec 2015 18:07:19 +0900
To: "'Tab Atkins Jr.'" <jackalmage@gmail.com>
Cc: "'www-style list'" <www-style@w3.org>
Message-ID: <008b01d12ce0$d90e8940$8b2b9bc0$@lge.com>
On Wed, Dec 2, 2015 at 7:03 AM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> On Tue, Dec 1, 2015 at 1:31 AM, Hyojin Song <hyojin22.song@lge.com> wrote:
>> There were a couple of concerns about media queries in Second Screen WG [1].
>> The Second Screen WG provides a mechanism to request display of Web content on a second screen with Presentation API [2]. It enables authors to make multi-device applications, and it would consider how to display Web content according to device capabilities.
>> 1. How could authors distinguish between several devices such as TV, projector for a responsive web?
>> In the mediaqueries4 [3], media types is defined as a broad category of user-agent devices on which a document may be displayed. However, I noticed that it is expected that all of the media types will also be deprecated in time, as appropriate media features are defined which capture their important differences.
> Yes. In fact, all media types are deprecated already, expect
> "screen", "print", and "speech", because we don't yet have sufficient
> MQs to replace them.  Media types are bad because they're exclusive
> and ill-defined, and attempt to capture a whole host of behaviors that
> aren't actually exclusive to the "device types" they talk about.
>> There are various use cases to display Web content differently according to device type. (e.g. media="projector"). What is the right place to refer it in Presentation API? Do we need additional works for an extension of media features to support this in CSS WG?
> Identify what aspects of the device are relevant to your purposes and
> different from other devices, and let us know so we can work together
> to come up with new MQs that capture those aspects.

I could understand that all media types were already deprecated except "screen", "print", and "speech", and the three remaining media types will be replaced by something like media features in mediaqueries4.

I looked into the media features, but I guess it's not the right category to identify physical device types. I would like to focusing on the physical device types(e.g. tv, projector, signage), not device capability(screen size, resolution), but I don’t yet know how to capture those physical device types.

There would be some usecase to display Web content differently between tv and projector, even though a resolution and a screen size are same in both devices. When I tested some multi-device application rendered differently according to device type such as TV, PC, it's not easy to distinguish between the devices. I used to exploit userAgent object as a trick way.

For what I know about CSS, There is no way to identify between the physical devices, while media="projector or tv" which was a deprecated feature could be possible to distinguish the devices.

How could CSS provide a sort of media selectors for tv, projector without the media types?

>> 2. Is it possible to define a media query for a non-interactive display?
>> I would like to see it would be possible to define a media query for a non-interactive display. Script could use it indirectly to enable input handlers for presentations that work with both interactive or non-interactive displays.
>> For example, a regular projector, or a smart board with a stylus input. There is no need to support the input method in regular projector, if the smart board send Web content as part of multi-device app to the regular projector(or a digital signage) through Presentation API. They aren't connected with HDMI cable or mirroring tech. each other, even though it needs to understand the 2-UA mechanism in Presentation API [4].
> The (pointer) MQ is close to this.  If the projector device doesn't
> have any pointer capability (which feels likely for a
> "non-interactive" secondary display), then (pointer:none) will match
> it.  Is that sufficient?

Right. In the interaction media features section [5], it provides two media features(pointer, hover). I think it needs additional media features to cover other aspects of user interaction.

For example, when a mobile send a Web content to a tablet, it shows differently according to whether the tablet is connecting with a bluetooth keyboard or not. I guess the other input methods would be reviewed such as keyboard, gesture, voice. In addition, several use cases [6] triggered in Second Screen WG, could be referenced for this.


[1] http://www.w3.org/2014/secondscreen/
[2] http://w3c.github.io/presentation-api/
[3] https://drafts.csswg.org/mediaqueries4/#media-types
[4] http://www.w3.org/TR/presentation-api/#introduction
[5] https://drafts.csswg.org/mediaqueries4/#mf-interaction
[6] https://github.com/w3c/presentation-api/blob/gh-pages/uc-req.md
Received on Wednesday, 2 December 2015 09:07:54 UTC

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