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Re: [css-device-adapt] @viewport and "desktop" browsers

From: L. David Baron <dbaron@dbaron.org>
Date: Sat, 2 Mar 2013 20:53:26 -0800
To: Rune Lillesveen <rune@opera.com>
Cc: www-style list <www-style@w3.org>
Message-ID: <20130303045326.GA16188@crum.dbaron.org>
On Friday 2013-03-01 16:30 +0100, Rune Lillesveen wrote:
> This issue was added for the FPWD:
> 
> "ISSUE 1 in the current ED "dbaron: The question is, what does this
> do on the desktop browser? (And what's a desktop browser)"."
> 
> 
> Perhaps the term "desktop browser" is misleading. Currently the term
> is used in the Introduction and in the UA stylesheets sections.
> "desktop browser" in this context is a browser with an initial
> viewport width greater than a certain width (Something similar said
> in section 13 UA stylesheets).

I don't think that's the only relevant distinction.

I think the much more important distinction is whether the browser
displays pages using the desktop model where the viewing area is the
same as the CSS viewport, or using the mobile model where the user
can pan and zoom within the CSS viewport so they are viewing only
part of it (with this panning and zooming also replacing the
function of any scrolling on the viewport).  In other words, is the
user's viewport the same as the CSS viewport, or are there two
different viewports?

The purpose of <meta viewport>, and presumably also @viewport, is to
describe behavior that applies in the second case but not the
first.  It describes the size of the CSS viewport and the
relationship between the two viewports on implementations where the
two viewports can differ; it should be ignored when the viewports
are tied together (as they are in desktop browsers).

> So what happens if a document with @viewport styles is shown in a
> "desktop browser"? Basically the same as in a small screen browser
> modulo the UA styles. One difference could be that between browsers
> which have magnifying-glass type zoom and those who don't. The
> Conformance section says a UA still can conform without support for
> actually changing the zoom factor.

I think a desktop browser with magnifying-glass type zoom is still
substantially different from a mobile browser.  In the desktop
browser with magnifying-glass type zoom, the viewports are still the
same by default, which is not the case in a typical mobile browser
(where, when a page is loaded, there is typically at least one of
pixel scaling or two viewports, if not both).

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂
Received on Sunday, 3 March 2013 04:54:04 GMT

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