W3C home > Mailing lists > Public > www-style@w3.org > February 2008

Definition of 'width' on columns

From: L. David Baron <dbaron@dbaron.org>
Date: Tue, 26 Feb 2008 12:21:52 -0800
To: www-style@w3.org
Message-ID: <20080226202152.GA8944@ridley.dbaron.org>

[ moving to www-style; a proposed resolution was sent to w3c-css-wg,
  which I'm not quoting ]

Issue 1 in http://csswg.inkedblade.net/spec/css2.1 is currently:
# Issue 1
#
# URL
#     http://lists.w3.org/Archives/Member/w3c-css-wg/2007AprJun/0429.html
# Summary
#     What should 'width' on columns and column groups really mean?
# Status
#     Needs proposal

I have the following comments on the proposal:

I tend to think that 17.3 should just point to 17.5.2 for the actual
behavior of 'width'.  17.5.2.1 already seems adequate for fixed table
layout; 17.5.2.2 ought to say more about auto layout.


For 'auto' table layout, we need to say what the 'width' property
defines.  I think:
 * it defines something that other things are able to increase, but
   not decrease
 * it defines a preferred width (not a minimum width) (what CSS 2.1
   actually calls "MAX").  The column width can become narrower due
   to other constraints (down to "MIN").

(Does anything in the spec actually say that the border-box width of the
cell is the same as the width of the column?  It probably should.)


For 'fixed' table layout, we probably don't need any changes, except
that we need to refer to 17.5.2.1 rather than define things
incorrectly in 17.3.


We also need to define what 'width: auto' on columns and column
groups does; I think it behaves the same as '0' (which makes sense
since it's just establishing one of a number of minima on the
preferred width).


We also need to define the behavior of 'min-width' and 'max-width'
on columns and column groups.  It's relatively simple to make them
not be ignored:  just say that the width property (after 'auto' is
converted to '0') is adjusted by max-width and min-width (in that
order) before being used.  (I'm not sure enough browsers implement
them for us to exit CR, although Firefox 3 will.)

We should also specify what happens for column groups (which I think
should be the same as for columns; i.e., the width applies to each
column separately, for compatibility with HTML and existing
implementations).

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/
Received on Tuesday, 26 February 2008 20:22:08 GMT

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