Re: Why no compositional positioning?

On 16 Mar 2009, at 15:40, Tab Atkins Jr. wrote:

> On Mon, Mar 16, 2009 at 9:28 AM, Thomas Davie <tom.davie@gmail.com>  
> wrote:
>> Thanks, okay, I don't yet fully understand what's going on here  
>> then.  I
>> have an example which I expect to produce a table using divs (yes,  
>> I know,
>> this is as bad as producing divs using tables, but it's a good  
>> example of
>> trying to achieve a certain layout and apparently being stymied by  
>> css:
>>
>> http://www.cs.kent.ac.uk/people/rpg/tatd2/test.html
>>
>> I had assumed previously that absolute positioning was positioning  
>> elements
>> relative to the top-left of the document window, causing the  
>> absolutely
>> positioned elements to not be part of their parent div, and hence the
>> relatively positioned ones to have a height of 0.  Apparently  
>> though this is
>> not what's happening.
>
> Absolute positioning removes an element from the document flow.  This
> means, among other things, that parent elements no longer use it to
> determine their height; they no longer 'contain' the abspos element.
> Thus, if you abspos all the children of an element, that element no
> longer has *any* in-flow content, and collapses to 0 height.
>
> You're not seeing a contradiction, you're just seeing multiple effects
> in play.  Note that even in your example it's clear that the abspos
> elements are positioning themselves based on their parent, as the
> elements are offset from each other by several pixels, due to the
> borders on the collapsed parents making their height non-zero.

That sounds like a very strange contradiction indeed actually.  The  
elements are positioned within their parent but are not in their  
parent.  Is there a reason for this strange behavior?

Incidentally, this returns me to my original question – there is no  
positioning mode which simply lays the elements out within their  
parent.  Why not?

Thanks

Bob