Re: [CSS21] Proposal for a replacement for section 17.2.1 (table anonymous objects)

On 7/20/10 8:27 PM, Tab Atkins Jr. wrote:
> (1) All implementations will have to change slightly, to avoid
> generating a "placeholder cell" when a run of abspos/fixpos elements
> have a "tabular container" parent.
> This isn't as bad as it sounds, though - I believe all implementations
> have to change already to implement fantasai's original algorithm, as
> they all interpret the ambiguous text in the current spec in different
> ways.

A few comments here, just so we're all on the same page:

1)  This is not a slight change, at least for Gecko.  It requires either 
a complete rewrite of the way absolute positioning is done or some 
extensive and scary (in the "exploitable security bug" sense) changes to 
table layout.  I can't speak to other implementors, obviously, but I 
don't expect us to change this behavior anytime soon.  I also still 
think that changing it would have enough web compat risk given existing 
interop that it may not be able to be changed at all.

2)  Currently shipped gecko matches my proposed algorithm (after a 
complete revamp of this code and earlier discussion on this list). 
Insofar as fantasai's algorithm matched mine, we would not in fact have 
to make any changes.

> (2) Determining the static position of abspos/fixpos elements with a
> "tabular container" parent is explicitly undefined in CSS2.1, to be
> fixed up later in CSS3.

That's not acceptable to me, and I expect to file a formal objection to 
that effect.  Again, this is an area where we _right_now_ have interop 
and you're proposing throwing that away and chasing after theoretical 
purity while introducing new sources of incompatibility.  Why do we want 
to do this?


Received on Wednesday, 21 July 2010 01:40:13 UTC