W3C home > Mailing lists > Public > www-style@w3.org > May 2010

Re: Questions about 'column-span'

From: David Hyatt <hyatt@apple.com>
Date: Fri, 21 May 2010 13:26:14 -0500
Cc: Bert Bos <bert@w3.org>, "www-style@w3.org list" <www-style@w3.org>
Message-id: <4E87680B-F424-4398-90F3-AF758703099F@apple.com>
To: David Hyatt <hyatt@apple.com>
On May 21, 2010, at 12:54 PM, David Hyatt wrote:

> 
> On May 21, 2010, at 12:42 PM, David Hyatt wrote:
> 
>> 
>>> (c) No, the spec says that a multi-column element is the root of a block 
>>> formatting context, so its margins do not collapse with its children's 
>>> margins. (In a way that's a pity, but it's what the spec says...)
>>> 
>> 
>> That's not what WebKit does.  We let the margin on an element in the first column collapse through the multi-column block, but we could change that if we have a solution that will auto-drop the margin off the first <p> in a column.
>> 
> 
> Oops, I was wrong about this.  It looks like we just drop the margin at the top of the first column.  Firefox does the same.
> 
>> This seems like an issue we need to correct somehow.  I mean if you have a multi-column block with a sequence of paragraphs, we can't have the first paragraph starting 1em into the column.  That would just look silly.  Authors shouldn't have to worry about resetting the top margin on the first element in a column.  They don't have to worry about it on the first page of a printed document or at the top of the document in continuous media...
>> 
>> The simplest way to resolve this issue may be to just apply the rule I suggested above, i.e., that you think of the top of the first column kind of like the top of a page, and let the margins resolve to 0.  This seems reasonable to me, since starting a column is somewhat similar to an unforced column/page break.
>> 
> 
> This rule above is what Gecko and WebKit both seem to be doing.  Is this specified somewhere and I'm just missing it, or do we need to make sure this rule gets added somewhere?


Bah, sorry for the list spam.  I screwed up the test I wrote.  I need to sleep more. :)

I was right the first time.  Both Gecko and WebKit do collapse margins out through multi-column blocks.  If that's considered incorrect behavior, we will need to change the spec to either make it ok or to specify something like what I mentioned above with discarding margins as though you have an unforced break.

dave
Received on Friday, 21 May 2010 18:26:49 GMT

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