Re: [CSS Intrinsic & Extrinsic Sizing] sizing of absolutely positioned elements

On 10/10/2012 00:05, Boris Zbarsky wrote:
> There's an unfortunate tendency to use the term "containing block" to
> refer interchangeably to "the rectangle defined as the containing block"
> (which is not itself a block in any way; it's just a rectangle) and "the
> element which was used when defining the containing block" (assuming
> there was one at all; see initial containing block) and maybe a few
> other things.
> As defined, right now, the containing block is a rectangle.  The other
> uses are just confused, to a greater or lesser extent.

Yup. Various people have raised these confused uses in CSS21 over the 
years.  When I last looked through (in response to a detailed post by 
Peter Moulder, IIRC) I got the distinct impression that the containing 
block used to refer to a real block (box) in times gone by... but then, 
I imagine, the definition got repeatedly tweaked to account for eg 
abspos, and suddenly the containing block became a mere rectangle and 
various bits of existing spec text became out-of-kilter (not to mention 
that the term itself became seriously misleading).

No post-CSS21 spec should be using the term to mean anything other than 
a rectangle, though (modulo the pending issue about containing blocks 
established by a principal inline box that's split across multiple lines).

Anton Prowse

Received on Tuesday, 9 October 2012 22:57:18 UTC