- From: Bert Bos <bert@w3.org>
- Date: Wed, 2 Mar 2011 17:31:14 +0100
- To: W3C style mailing list <www-style@w3.org>
On Wednesday 06 October 2010 18:44:43 Boris Zbarsky wrote:
> On 10/6/10 12:28 PM, Bert Bos wrote:
> > 2. For other elements, if the element's position is 'relative'
> >
> > or 'static', the containing block is one of the following:
> > a. If the element is a 'run-in' that is rendered inline
> > in a
> >
> > sibling element, then its containing block is the
> > content edge of the principal box of that sibling.
> >
> > b. Otherwise, if the parent has a principal box that is a
> > block
> >
> > container box (e.g., if the parent is a 'table-cell'
> > or a 'block'), then the containing block is the
> > content edge of the parent's principal box.
> >
> > c. Otherwise the containing block is the same as that of
> > the
> >
> > parent.
Here is an updated proposal, removing 'run-in' and inserting anonymous
table cells instead.
Bullet 2 of 10.1 (Definition of "containing block") currently reads:
| 2. For other elements, if the element's position is 'relative' or
| 'static', the containing block is formed by the content edge of
| the nearest block container[ref] ancestor box.
Before the latest WD, it read:
| 2. For other elements, if the element's position is 'relative' or
| 'static', the containing block is formed by the content edge of
| the nearest block-level[ref], table cell or inline-block ancestor
| box.
Issues to solve:
a) (Issue 142.) The spec defines the terms "block container box" (a type
of box) and "ancestor" (a type of element) and thus "block container
ancestor box" is loose language and needs to be made precise.
b (Issue 197.) Because of difficulty finding sufficiently many
implementations in the short term, we decided[1] to leave 'run-in' out
of level 2.
c) There is probably a consensus for letting anonymous table cells,
unlike other anonymous block boxes, form a containing block for their
content.
d) Until the latest WD, bullet 2 said these elements established
containing blocks: 'block', 'list-item', 'caption', 'inline-block',
'table-cell' and 'table'. The latest WD removed 'table'. I think that
was unintentional. And probably 'inline-table' should be added.
All that leads to this replacement text:
# 2. For other elements, if the element's position is 'relative'
# or 'static', the containing block is one of the following:
#
# a. If an anonymous table-cell is generated to contain the
# element (i.e., if the parent is a tabular container[2]
# and the element itself is not a table-cell, see section
# 17.2.1[3]), then the containing block is the content edge
# of that anonymous table-cell.
#
# b. Otherwise, if the computed value of the parent's 'display'
# property is 'block', 'list-item', ['inline-table', 'table',]
# 'caption', 'inline-block', or 'table-cell, then the
# containing block is the content edge of the parent's
# principal box.
#
# c. Otherwise the containing block is the same as that of the
# parent.
... where the bracketed text ['inline-table', 'table',] in (b) is yet to
be decided.
[1] http://www.w3.org/blog/CSS/2011/01/27/resolutions_145
[2] http://www.w3.org/TR/CSS2/tables.html#tabular-container
(anchor doesn't exist yet)
[3] http://www.w3.org/TR/CSS2/tables.html#anonymous-boxes
Bert
P.S. There is a small inconsistency between 17.4 (Tables in the visual
formatting model[4]) and 9.2.1 (Block-level elements and block
boxes[5]). The former talks about "principal block box" while the latter
calls it a "principal block-LEVEL box." I vote for the shorter name.
[4] http://www.w3.org/TR/CSS2/tables.html#model
[5] http://www.w3.org/TR/CSS2/visuren.html#block-boxes
--
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 Wednesday, 2 March 2011 16:31:43 UTC