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Re: [CSS21] min-height: 100% in html, body

From: Øyvind Stenhaug <oyvinds@opera.com>
Date: Mon, 30 Jan 2012 16:30:32 +0100
To: www-style@w3.org
Message-ID: <op.v8wlc6wpbunlto@oyvinds-desktop>
On Fri, 27 Jan 2012 21:41:19 +0100, Simon Sapin <simon.sapin@kozea.fr>  

> Le 27/01/2012 18:02, Øyvind Stenhaug a écrit :
>> First of all, the term "specified explicitly" seems nonsensical. All
>> elements have a specified value. On the other hand, the containing block
>> isn't an element, and isn't necessarily even related to one. So the
>> parentheses actually contain the crucial part here (and readers must
>> figure out for themselves how exactly to determine whether the  
>> containing
>> block depends on content height).
>> Now, the main issue: even if assuming the simple case where the  
>> containing
>> block corresponds to some particular dimensions of an ancestor block
>> element's sole box, exactly which value does "the height" refer to?
>> - The so-called tentative used height? ("Depends on content height" in  
>> the
>> example)
>> - The used value? (Does not "depend on content height" in the example)
>> (- Something else?)
> Hi,
> I agree this should be more explicit, but I think it is the computed  
> value. A computed value of 'auto' is the only case where the used height  
> depends on the content:

I don't know if that's what the spec author was thinking, but it's not  
that simple.

a) display: table-cell; height: 0;

Computed value of 'height' is not 'auto', but used value of 'height' still  
depends on the content...

b) position: absolute; top: 0; bottom: 0; height: auto;

Computed value of 'height' is 'auto', but used value of 'height' does not  
depend on the content.

> According to 10.1, a containing block is one of :
> 1. The viewport
> 2. A page area
> 3. The content edge or padding edge of a block container
> 4. The bounding box around the padding boxes of ... something. I’m not  
> sure how exactly that one works. (Can an inline element generate more  
> than one inline-level boxes while *not* being split across lines?)

(Yes, e.g.
<div dir="ltr"><span>english WERBEH</span> WERBEH</span></div>
where the uppercase parts represent right-to-left letters)

> 1 and 2 always have a fixed height. I’m not sure about 4, but for 3 it  
> depends on the 'height' property. The height is "specified explicitly"  
> if and only if the 'height' property dos not compute to 'auto'.

Such a definition is not compatible with what browsers actually do, and is  
inconsistent with the "depends on content height" parenthetical, as shown  

Øyvind Stenhaug
Core Norway, Opera Software ASA
Received on Monday, 30 January 2012 15:31:10 UTC

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