Re: [css-contain] Layout containment and overflow

On Fri, Feb 26, 2016 at 2:56 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> 1. Eh, let it happen. It's not too bad.
> 2. Layout containment always implies paint containment, so nothing can overflow.
> 3. Overflow is allowed visually, but it doesn't project its "geometry"
> past the layout-contained ancestor, so it can't trigger overflow past
> a layout-containment boundary.
>
> I talked to Levi, our 'contain' implementor, and he said he hates both
> #1 and #2, and that our code already effectively does #3 - when a
> contain:layout box overflows, its ancestors aren't informed, so they
> don't "see" the overflow and won't respond with scrollbars.  Painting
> is still done normally, so the overflow shows up visually.
>
> So, I'm going to spec that.

And while editting this in, I realized there was an explicit note
calling this situation out, and claiming you needed to be
paint-contained as well to achieve the "offscreen element has zero
effect on layout" to avoid a protruding element causing scrollbars.
I've removed this note. ^_^

~TJ

Received on Friday, 26 February 2016 23:03:00 UTC