Re: [css3-backgrounds] Should a non-zero border-radius create a new stacking context ?

On Nov 20, 2010, at 8:25 AM, Sylvain Galineau wrote:

> I never said it shouldn't clip to the inner corner curve. That's not at all the point. If the element with border-radius in my original testcase created a new stacking context then the blue box moves below the green one (as it also will if you give the parent opacity < 1, or a transform). It still must clip to the parent's curve within that parent's stacking context. 
> 
> So no one is questioning whether the element should clip to the border curve.

OK, I thought that was part of what you were questioning, because your statement "It's not  clear to me why this is useful or desirable" seemed to be questioning something that was already in the spec. And the spec has no special implications for stacking contexts that I can see.

> The suggestion is that the non-zero radius would result in a different z-order for the blue box.

I see no reason why it would or should.


On Nov 20, 2010, at 8:42 AM, fantasai wrote:

> What Brad is saying is that the problem you're running into wrt stacking
> contexts has nothing to do with whether the border is curved or square.
> (Give the element some negative margins, and you'll get the same behavior
> with a square border.)
> 
> Having non-zero border radius affect the z-order doesn't follow from the
> problem you describe: it's not creating any new or interesting stacking
> effects. It's just changing the shape of the clip mask.


Right.