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Re: [css3-regions] content:flow-from() vs. flow-from

From: Alan Stearns <stearns@adobe.com>
Date: Wed, 10 Aug 2011 18:42:54 -0700
To: Alex Mogilevsky <alexmog@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <CA6881AE.6F2A%stearns@adobe.com>
On 8/10/11 4:07 PM, "Alex Mogilevsky" <alexmog@microsoft.com> wrote:

> I would like to revisit the issue of named-flow property
> 
> "content:flow-from(flowname)" vs. "flow-from:flowname"
> 
> We did have a WG resolution for 'content', but at the time of the discussion
> the difference appeared to be purely syntactical, however it isn't, as
> described here:
> 
> http://lists.w3.org/Archives/Public/www-style/2011Jul/0477.html
> 
> In short:
> 
> * 'content' replaces natural content of the element, combining it with any
> ':before' and ':after', potentially with fallbacks, while
> * 'flow-from' takes over the whole box, giving it a different layout model
> (where ':before' and ':after' have no meaning)
> 
> It is possible to define how before/after blend with flow content in a subset
> of region use, but it is something that was never called for, yet it is
> complicated to define and implement.

The regions spec currently defines ::region-before and ::region-after, which
"...have the same definition as the Œ::beforeš and Œ::afterš
 pseudo-elements" but a different processing model.

Why not ditch those and give ::before and ::after meaning in a region
context equivalent to what you plan to do for ::region-before and
::region-after? Then the current issue with content:flow-from() goes away.

Option 5:
 1) "content:flow-from()" defines a region (no change)
 2) css-regions updates section 4 to use pre-existing pseudo-selectors

I'd further like to pursue making ::before and ::after behavior with regions
be as close to other elements as possible. This version of the spec might
note that inline use would be desirable but admittedly difficult, so
something like this would be required:

Content content content content content
                (...continued on page 3)

But something like this would merely be a recommendation at this point in
time, and could fall back to the behavior above:

Content content (...continued on page 3)

> More issues with 'content':
>     * It seems backward that we are using a special value of 'content'
> property to change the nature of the container, and change how some selectors
> apply (:before/:after).

My preference when encountering differences between regions and other
elements is to reduce the differences. The more we can re-use existing
concepts, the better regions will fit into CSS as a whole.

Alan
Received on Thursday, 11 August 2011 01:43:33 GMT

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