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

Re: Issue 101 Resolution

From: Anton Prowse <prowse@moonhenge.net>
Date: Thu, 21 Oct 2010 19:45:29 +0200
Message-ID: <4CC07C39.4040701@moonhenge.net>
To: www-style list <www-style@w3.org>
CC: Alan Gresley <alan@css-class.com>, "Tab Atkins Jr." <jackalmage@gmail.com>, Peter Moulder <peter.moulder@monash.edu>
On 21/10/2010 08:06, Alan Gresley wrote:
> Tab Atkins Jr. wrote:
>> On Wed, Oct 20, 2010 at 11:05 AM, Anton Prowse wrote:
>>> On 20/10/2010 18:05, Tab Atkins Jr. wrote:

> I do see this in the
> spec 10.1 (Definition of "containing block" ) point 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, table cell or inline-block
> | ancestor box.
>
> So in dbaron's test for rule 3, the containing block of the left floated
> box is the aqua box and the containing block of the aqua box is the
> yellow box. So the change now reflects the concept of nearest
> block-level ancestor.

I have no idea what you're getting at here.


>>>> Suggested text:
>>>> | A left-floating box that has another left-floating
>>>> | box to its left, where the latter box's right edge
>>>> | is to the right of the original left-floating box's
>>>> | containing block's left edge, may not have its right outer
>>>> | edge to the right of its containing block's right
>>>> | edge. (Loosely: a left float may not stick out at
>>>> | the right edge, unless it is already as far to the
>>>> | left as possible.) An analogous rule holds for
>>>> | right-floating elements.
>>> s/original left-floating/former/
>>
>> Good catch; that makes the text cleaner.
>>
>> New rule 3 text (I overcorrected for "outer edge"):
>> | The right outer edge of a left-floating box may not
>> | be to the right of the left outer edge of any
>> | right-floating box that is to the right of it and
>> | whose left outer edge is to the left of the
>> | left-floating box's containing block's right edge.
>> | Analogous rules hold for right-floating elements.
>>
>> New rule 7 text (slightly cleaner):
>> | A left-floating box that has another left-floating
>> | box to its left, where the latter box's right edge
>> | is to the right of the former box's containing
>> | block's left edge, may not have its right outer
>> | edge to the right of its containing block's right
>> | edge. (Loosely: a left float may not stick out at
>> | the right edge, unless it is already as far to the
>> | left as possible.) An analogous rule holds for
>> | right-floating elements.
>>
>
> Can the above parts that have "containing block's right edge" be changed
> to "containing block's right content edge".
>
> s/containing block's right edge/containing block's right content edge/

No, no.  The containing block doesn't have a "content edge"; it's a 
rectangular region.


> <!DOCTYPE html>
> <div style="float: right; width: 400px; height: 100px; background:
> green;">Right</div>
> <div style="float: left; width: 80px; height: 80px; margin-right:-100px;
> border: 10px solid blue;">Left</div>
>
> Narrowing the viewport, Gecko and IE8 will allow the right floating box
> (green) to pass under the left floating box (blue border) and go into
> the hidden overflow. Opera, WebKit and IE9 shows the left floating box
> (blue border) dropping when the left outer edge of the right floating
> box passes the left content edge of the 'initial containing block'.

The dropping is correct, right?  This is simply Rule 3 in its 
traditional form (and of course in its newly proposed form too, since 
it's backwards compatible).  The containing block is only tangentially 
relevant.

> I believe that Gecko and IE8 behavior is correct since the left floating
> box (blue) right outer edge (margin edge) sit on the same vertical axis
> as it's left outer edge. This means the float takes
> up no horizontal space in it's containing block as the below test shows.

Whether it has zero- or negative-width margin area is irrelevant.  The 
only thing that matters is the location of its right outer edge.  (See 
also the related discussion in [1,2] where we're dealing with line boxes 
rather than right floats.)


[1] http://lists.w3.org/Archives/Public/www-style/2010Aug/0182.html
[2] http://lists.w3.org/Archives/Public/www-style/2010Sep/0129.html

Cheers,
Anton Prowse
http://dev.moonhenge.net
Received on Thursday, 21 October 2010 17:46:44 GMT

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