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Re: [css3-regions] issue: is first region initial containing block

From: Brad Kemper <brad.kemper@gmail.com>
Date: Wed, 8 Feb 2012 08:52:09 -0800
Message-Id: <AA651BD1-20DD-426B-8BEF-9E1F47ED3C90@gmail.com>
Cc: Vincent Hardy <vhardy@adobe.com>, Anton Prowse <prowse@moonhenge.net>, "www-style@w3.org" <www-style@w3.org>
To: Alex Mogilevsky <alexmog@microsoft.com>
On Feb 8, 2012, at 1:28 AM, Alex Mogilevsky <alexmog@microsoft.com> wrote:

>> From: Brad Kemper [mailto:brad.kemper@gmail.com]
>> Sent: Tuesday, February 07, 2012 6:34 PM
>> 
>> What it the purpose of this restriction? If authors wants that behavior, they can
>> just set 'position:relative' on the first block. Why must it be prescribed as a
>> containing block?
> 
> Set position:relative on first region or root element of named flow?

I'm confused by the question, because "root element of named flow" is meaningless to me (or, has been meaningless, or should be meaningless). The root of any HTML document I'd the HTML element viewport, and there is only one root per document.

I had meant that the author could set position:relative on first region, instead of the first region being the ICB. It seems like that would amount to the same effect, except that it wouldn't be mandatory (the author could leave the first region as static, and the HTML element would remain the true root.

> Both may work sometimes but not quite.
> 
> If first region is position:relative and it is the nearest positioned ancestor of absolute positioned element in named flow, positioned content will be literally relative to the first region, not in the fragmented flow.

That is what I would also expect if the first region was the ICB.

> Something positioned at "top:<first-region-height>" will be under the first region, not in second region (assuming that is what would happen in paged media -- defining that precisely is a separate issue).

Granted, it doesn't seem that useful to do it that way. But if it was left up to the author, then the author could set all the regions to position:relative, and then the abs-pos item would be positioned within whatever block it ended up in (or that it's placeholder ended up in, actually).

> If the idea is to set position:relative to root block of named flow - that's not even possible. There is no root block, or at best it is anonymous.

I think we agree on that, since I don't know what 'root block of named flow' means. Maybe I was reading that as 'initial block of named flow' before.

> It *can* be defined that if first region is positioned it becomes ICB, but it eliminates some behavior options, specifically the behavior I described above.

Which is positioning to the second region, right? I'd say thatcouldbehandled by,akingthesecond region or all regions 'position:absolute'.
Received on Wednesday, 8 February 2012 16:56:31 GMT

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