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Re: [css-device-adapt] How should initial viewport contribute to layout?

From: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Tue, 11 Feb 2014 17:39:52 -0800
Message-ID: <CADBxrie8XguA5eW4SweNqvxGz6rmmE+QijfO7fFyFESM2uCdZg@mail.gmail.com>
To: Matt Rakow <marakow@microsoft.com>
Cc: "www-style@w3.org" <www-style@w3.org>
>
>
> All this said, I'm not sure if these questions fall into the device
> adaptation spec since they pertain more to definition of visual viewport
> vs. actual viewport, rather than the definition of initial viewport vs.
> actual viewport.  I do think they'd be good questions to resolve in some
> spec though.
>

I think this is a good point. Do you mean we should distinguish 'visual
viewport' and 'initial viewport'?

Thanks,
> -Matt
>
>
> >From: wangxianzhu@google.com [mailto:wangxianzhu@google.com] On Behalf
> Of Xianzhu Wang
> >Sent: Tuesday, February 11, 2014 11:42 AM
> >To: www-style@w3.org
> >Subject: [css-device-adapt] How should initial viewport contribute to
> layout?
> >
> >Hi,
> >
> >Actually I have 2 related questions:
> >1. Should fixed-position blocks layout according to the 'initial
> viewport', 'actual viewport' or something between them?
> >2. For a page with unconstrained viewport height, how should the height
> of the 'actual viewport' be adjusted when there is temporary height change
> of the 'initial viewport', e.g. when the on-screen-keyboard shows?
> >
> >The answers to the above questions seem to have already been covered by
> existing specs, but after we examine the current behavior of different
> mobile browsers we found they have tweaked the existing specs to achieve
> more user-friendship and/or better performance:
> >
> >1. All browsers seems not to layout top-level fixed-position blocks
> according to the initial-containing-block (i.e. 'actual viewport' in
> css-device-adapt), but somehow according to the visible viewport (i.e.
> 'initial >viewport' in css-device-adapt). Mobile Safari's behavior is more
> complex that seems to use a bigger virtual viewport to contain the
> fixed-position elements if the visible viewport is too small.
> >
> >2. For a page with unconstrained viewport height, the browsers behave
> differently about whether to adjust the actual viewport height when
> visibility of the top- and/or bottom- controls and the on-screen keyboard
> changes.
> >
> >
> https://docs.google.com/a/chromium.org/document/d/1ukfEZGJQq-7VD_Tv9m_cYD4BoR6YZots5_KddtvYZJs/edit#summarizes the current behaviors of the browsers.
> >
> >I think it'd be better if the spec address the issues that caused the
> browsers to tweak the spec, to avoid inconsistency and confusion.
> >
> >Thanks,
> >Xianzhu
> >
>
Received on Wednesday, 12 February 2014 01:40:20 UTC

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