RE: [manifest] screen sizes, Re: Review of Web Application Manifest Format and Management APIs

Re "At install time or when I am browsing apps, how does a server know my screen resolution? Or is this restriction imposed on by the user agent?": When browsing apps, the server can easily access the screen and window DOM attributes. When installing apps, the installer (browser, app manager, etc) can provide a warning to the user that the app is designed for use on larger screens, and may not work properly on this device.

Thanks,
Bryan Sullivan 

-----Original Message-----
From: Marcos Caceres [mailto:w3c@marcosc.com] 
Sent: Sunday, May 27, 2012 1:35 AM
To: Anant Narayanan
Cc: SULLIVAN, BRYAN L; public-webapps@w3.org
Subject: Re: [manifest] screen sizes, Re: Review of Web Application Manifest Format and Management APIs



On 26 May 2012, at 18:32, Anant Narayanan <anant@mozilla.com> wrote:

> On 05/25/2012 09:25 AM, Marcos Caceres wrote:
>> 
>> 
>> On Friday, May 25, 2012 at 4:34 PM, SULLIVAN, BRYAN L wrote:
>> 
>>> Marcos,
>>> 
>>> Re "I thought we had stopped the whole designing for particular screen sizes, etc. a long time ago.", that may be the still-closely-held goal, but the reality is that designing for multiple screen sizes (and pixel densities) is still far from simple. Even with all the tools that have been developed in CSS and Media Queries.
>>> 
>>> So if developers want to claim that they have focused their design on specific form factors (and presumably tested it thoroughly on them), this seems like a good thing as it allows them to be more certain that their apps won't be distributed to users of devices on which they won't work well (which will negatively impact the developer's reputation, use of the app, appstore etc), or if distributed to such users, will be clearly identified as not being designed for those devices.
>>> 
>>> Like many of the things we wanted to do in widget manifest structures in BONDI and WAC, if these get pulled from the plan the only fallback is developer ecosystem-specific app metadata, which in the end evaporates with the developer ecosystems, or never achieves widespread use or interoperability. So the problem is not solved for developers by leaving these things out of standards, where there is a strong use case.
>>> 
>> 
>> Still sounds to me like "Made for<insert everyone's favorite 90's browser here>, and best viewed at 800x600" … and look how well that turned out. Even if we don't focus on mobile devices, it seems like a silly requirement as I can just adjust my browser window to whatever size I want (there is no reason to believe I won't be able to do that on future mobile devices). I.e., screen size and application display area are not the same thing and this metadata attribute seems to assume so.
> 
> The intent for the screen_size parameters is not to let the developer enforce a particular screen size or resolution, but rather specify the *minimum* width and height required by the app. This means that on a screen below the specified size, the app will not function at all.

To make this more clear, maybe call this min_screen_size. 

> 
> I will also note that it is upto the app store to interpret this field however they'd like. If they do not want to disallow installs on devices that don't meet the developer-specified criteria, that's fine. However, we should still convey this information from the developer to the store via the manifest.

At install time or when I am browsing apps, how does a server know my screen resolution? Or is this restriction imposed on by the user agent?

> It is unrealistic to assume that all app developers will make a responsive design for all possible screen sizes. The tools aren't great and it costs time and money. We added this field after we received a request from the developer of a popular game that only worked on desktops, but not mobile phones (due to size). They wanted to make sure users weren't able to install them in places the app wasn't designed for and get a bad impression of the company. I think this is really important.

I think that's fine, but as Scott pointed pointed out, user agents have a history of allowing users to bypass these kinds of restrictions (or users hack around them). I think this field can only really serve as a warning that the app might not work as expected.

Received on Sunday, 27 May 2012 11:38:00 UTC