[css3-align] true/safe align/justify WAS: [css3-flexbox] alignment and overflow:scroll

I'm fine with this under the assumption that all the justify/align keywords
right now do "true" alignment. That does mean that
http://dev.w3.org/csswg/css3-align/ has things backwards though. Instead of
a "true" keyword to make things overflow the head edge of the container, we
need a "safe" keyword to make things not overflow the head edge.

I'm not sure "safe" is the best word for it though. Really this is just
about the overflow being scrollable. So..."scrollable-overflow"? That's a
bit verbose and obscure...but maybe it's better than "safe".

Ojan


On Tue, Mar 12, 2013 at 2:25 PM, Tab Atkins Jr. <jackalmage@gmail.com>wrote:

> On Tue, Mar 12, 2013 at 10:13 AM, Tony Chang <tony@chromium.org> wrote:
> > On Tue, Mar 12, 2013 at 8:27 AM, Tab Atkins Jr. <jackalmage@gmail.com>
> > wrote:
> >> On Mon, Mar 11, 2013 at 3:56 PM, Tony Chang <tony@chromium.org> wrote:
> >> > Where is the cross-end?  Is it the bottom of the flexbox (100px),
> >> > causing
> >> > the flexbox to overflow out the top, or should the scrollable area
> >> > extend to
> >> > 200px tall?
> >>
> >> Here, we do the same things we did previously, except when we come to
> >> step 14.  Now, because the alignment is 'flex-end', it doesn't have
> >> its height adjusted, and just aligns its cross-end edge with that of
> >> the flexbox. So, yes, it then overflows out the top.  However, because
> >> scrolling containers don't show their overflow, and you can't scroll
> >> past the top of an element, the overflowing part is simply clipped and
> >> is completely inaccessible.  (If we ever allowed scrollable areas to
> >> scroll into negative positions, you could get to it.)
> >
> > Just to be clear, you're saying that there would be no scrollbar and we
> > would clip the top 100px of the image.  Likewise, if the flex item had
> > align-self: center, we would clip the top 50px of the image.  This seems
> > reasonable to me too.
>
> Well, there will be a scrollbar in this case, because you specified
> "overflow: scroll;", but yeah, it'll be disabled since there's nothing
> extending out of view in the scrollable area. If you had "overflow:
> auto;", there would be no scrollbar at all.
>
> And yes, with "center", you'd clip the upper 50px and let people
> scroll to the lower 50px.
>
> ~TJ
>
>