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Re: [CSS Regions] Update available

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 31 Mar 2011 14:37:20 -0700
Message-ID: <AANLkTinVDQjL_3kz-23G=79mq-WwZ1nC2Bho2uaCTiRj@mail.gmail.com>
To: Arno Gourdol <agourdol@adobe.com>
Cc: "www-style@w3.org" <www-style@w3.org>
On Fri, Mar 25, 2011 at 12:49 PM, Arno Gourdol <agourdol@adobe.com> wrote:
> We have an update of our CSS Regions proposal. You can find it here:
> http://dev.w3.org/csswg/css3-regions/
>
> First, apologies for the unprocessed document. This will be resolved
> promptly. In the meantime, please click Overview.src.html in directory above
> to get to the document.
> This version incorporates some of the feedback we've received at the F2F
> meeting and on this mailing list. Thanks to everyone for your suggestions
> and comments.
> The document has been broken up in three major sections: slots (which
> describe a way of creating elements using CSS declarations and could be used
> for regions and other purposes), regions (which are a way of implementing
> story threading) and exclusions (to specify areas to be avoided for the
> purpose of text layout).
> We would be very interested in feedback regarding the structure of the
> document, and whether these proposals should remain in one document, be
> merged with other proposals, or separated in multiple documents.
> We also look forward to feedback regarding the new proposed syntax.

Comments on the Slots section:

1.
Slots should be pseudo-elements in the same way that ::before,
::marker, etc. are.  In particular, this means that they are *not*
selectable by normal selectors.  They're created as anonymous elements
in the CSS element-tree by setting their 'content' property to
something other than 'none', that's it.

This also means that doing something like the example in the draft
(lightly modified to remove some parts irrelevant to this comment):

body::slot() { content: "first slot"; }
body::slot() { content: "second slot": }

...just creates a single slot, with the text "second slot" inside of
it.  This is exactly identical to how ::before would work in the same
situation:

body::before { content: "first before"; }
body::before { content: "second before"; }

If you want multiple slots on the same element, they should be
named/numbered differently.  Either of the following two examples
should create two slots, as expected:

/* Two named slots */
body::slot(foo) { content: "first slot"; }
body::slot(bar) { content: "second slot": }

/* Two anonymous numbered slots? */
body::slot(1) { content: "first slot"; }
body::slot(2) { content: "second slot": }

(We may or may not want anonymous numbered slots.  It's not a big deal
either way - you can just name them with a numbered token, like "s1"
and "s2".)

*************

2.
I don't understand the need for the %slot-name syntax.  If you want a
slot to have slots for some reason, you should just chain the
::slot()s, like "body::slot()::slot()".  Pseudoelements aren't
currently chainable, but they should be.  Let's assume that this
functionality exists.

**************

3.
A bare "::slot()" selector should function exactly like it would if it
were any other pseudoelement, and create a slot on every element, just
like if you specified "*::slot()".  If you want a slot on root, just
say ":root::slot()".

***************

4.Feedback on Regions:

1.
This ability, itself, I think should be called Named Flows.  It's the
flows that we care about, after all.

****************

2.
In addition to the into(<ident>) function, which shunts the contents
into a Named Flow to be picked up by a ::slot() later, we should have
a cell(<ident> | [ <grid-row> <grid-column> ]) function, which flows
it directly into a Grid cell (cells would automatically have their
'content' set up appropriate to grab from the cell() flow, I guess).

*****************

3. In general, this seems like it's just an overflow capability.  Can
we bodge this ability into 'overflow' instead of creating a new 'flow'
property?  This might not be a good idea, actually; it would mean that
if you want to, for example, shift all of <body>'s contents into a
slot, you have to set 'overflow' appropriately and then set
"height:0", which sounds weird.

~TJ
Received on Thursday, 31 March 2011 21:38:12 GMT

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