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Re: [CSS21] Issue 232: meaning of "in-flow" (was Re: Issue 236 - does 'text-decoration' propagate into tables?

From: Bert Bos <bert@w3.org>
Date: Tue, 8 Mar 2011 08:03:14 -0800
Message-Id: <AF09EC47-D757-4461-83DF-E8C6F1CBE48A@w3.org>
To: W3C style mailing list mailing list <www-style@w3.org>
On Mar 4, 2011, at 15:55, Peter Moulder wrote:

> On Fri, Mar 04, 2011 at 09:30:16AM -0800, L. David Baron wrote:
>> On Friday 2011-03-04 09:36 +0100, Anton Prowse wrote:
>>> On 04/03/2011 04:15, fantasai wrote:
>>>> On 10/19/2010 05:56 PM, L. David Baron wrote:
>>>>> ...
>>>>> As far as I can tell, CSS 2.1 never defines the term "in-flow".
>>>>> 
>>>>> If "in-flow" is intended to refer to the definition of "normal
>>>>> flow", then tables are not in-flow.
>>> 
>>> How so?  The table wrapper box is either block-level or
>>> inline-level, right?  Moreover, so are the table box and table
>>> caption box.  So text-decoration should be propagated into captions.
>> 
>> Sorry, I should have said "then the contents of tables are not
>> in-flow relative to the parent of the table".  But otherwise the
>> point stands, as you note below.
> 
> Just a point of clarification: Anton above interprets table captions to
> be part of the normal flow.  "Contents of tables" is ambiguous whether it
> includes or excludes table captions, though personally I tend to read
> that term as including table captions, which would differ from Anton's
> interpretation of whether captions are in the normal flow.
> 
> I'm just making sure there's agreement on this point (though it's
> only relevant to the extent that "in the (same) normal flow (as X)"
> is a relevant concept in the spec; see further down).
> 
> 
> Something else that may be relevant to the meaning of "in-flow relative
> to X" is that the table wrapper box establishes a block formatting
> context (17.4 para 3).  I don't see that the phrase "in the same
> normal flow of X" is defined in the current text, so a reader might
> wonder whether something not in the same block formatting context as X
> is in the same flow as X or not.
> 
> I'm not saying that this is a desirable interpretation; I'm just saying
> that when we do provide a definition of "in-flow relative to X" (and
> any other phrases involving normal flow), then we should make it clear
> as to whether or not it includes things that are in different block
> formatting contexts.
> 
>> Well, "Hence" under the assumption of "in-flow" meaning "in the
>> normal flow".
> 
> I believe David is questioning whether "in-flow" in fact ought to mean
> "in the normal flow" as distinct from, say, "not floated or absolutely
> positioned".
> 
> I believe we do want a term meaning "an element or box that is not
> floated or absolutely positioned [though may be (or generate a box that
> is, in the case of an element) inside another box that is floated or
> absolutely positioned]", and we may well end up using the phrase
> "in-flow" for this.  Whereas some text does want a term that can be
> used for descendants, a term (phrase) that includes a "relative to X"
> qualifier, and that excludes boxes that are in a (different) float or
> abspos box than X (i.e. that have a float or abspos box between them
> and X in the ancestry chain).
> 
> It's less common to want a term that excludes table-cell descendants
> (I can't offhand think of a place that wants such a term), which is I
> believe what David is alluding to in the above explicit qualification.
> 
> pjrm.

Here is a proposed definition of in-flow and out-of-flow. Add in 9.3, after the list:

    An element or :before/:after pseudo element is called _out_of_flow_
    if it is floated, absolutely positioned, or is the root element.

    An element or :before/:after pseudo-element is called _in-flow_ (or:
    _in the normal flow_) if it is not out-of-flow.

    The _flow_ (a.k.a. _normal flow_) of an element A is the set consisting
    of A, all in-flow elements whose nearest out-of-flow ancestor is A, and
    the in-flow :before/:after pseudo-elements, if any, of all elements in
    the set.

NB. This says that internal table element are in-flow, because I didn't find an occurrence where it mattered. I hope I didn't miss any.



Bert
-- 
  Bert Bos                                ( W 3 C ) http://www.w3.org/
  http://www.w3.org/people/bos                               W3C/ERCIM
  bert@w3.org                             2004 Rt des Lucioles / BP 93
  +33 (0)4 92 38 76 92            06902 Sophia Antipolis Cedex, France
Received on Tuesday, 8 March 2011 16:08:50 GMT

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