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

Re: [CSS21] Auto height of block with horizontal scrollbar

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Fri, 27 Aug 2010 12:30:10 -0400
Message-ID: <4C77E812.7060007@mit.edu>
To: Řyvind Stenhaug <oyvinds@opera.com>
CC: www-style@w3.org
On 8/27/10 9:02 AM, Řyvind Stenhaug wrote:
> Well, if they increment the padding then they only do so for auto
> height, not when the height of the outer div is explicitly set to 100px.

Ah, ok.  That's interesting....  For an auto-height div, putting the 
scrollbar into the padding is clearly the right behavior from the 
standpoint of authors.  Otherwise any overflow:auto block with 
horizontal overflow and auto height would also be forced to have 
vertical overflow, right?  So I think we should make sure that the spec 
handles that case well.

>> It's not clear from section 11.1.1. whether the scrollbar insertion
>> changes the used padding value or whether the scrollbar is supposed to
>> "overflow" the padding, and if so in which direction. I would not
>> expect it to overflow out, since that would make it overlap other
>> content, so the options are either that the used padding is increased
>> or the used width/height is decreased, right? Or I guess that the used
>> margin is increased...
>
> Or the scrollbar is just painted on top of everything else, so that its
> end edge equals the end edge of the padding area ("overflowing" inwards).

That's the "used height/width is decreased" case, I think.  At least 
that's the way I was thinking of it.

> I've been wondering the same thing. I'm not sure why the text talks
> about modifying the dimensions of "the containing block" (block? blocks?
> as you mention further down, there isn't just one) and not just the used
> width/height.
> (<http://lists.w3.org/Archives/Public/www-style/2008Jan/0259.html>)

I have no idea.  :)

> Well, in this case the computed value of 'height' should be 'auto' per
> 10.5. My Safari/Firefox versions aren't as recent but they both seem to
> honor that part (as does Opera).

Oh, good catch.  So the width differences are still relevant, but the 
heights being about half was a complete accident.  And for width, the 
only case that was different was Opera's handling of the positioned 
block vs the other two engines' handling.

> Yeah, I guess there are some bugs in the more general behavior, I just
> focused on one case which seemed to be consistent.

Yeah, ok.  Let's stay on that one; as I said above, I think the 
consistent behavior is needed to make overflow:auto make sense.

-Boris
Received on Friday, 27 August 2010 16:30:48 GMT

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