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Re: [css3-align] Some questions about justify-self

From: Christian Biesinger <cbiesinger@chromium.org>
Date: Wed, 20 Mar 2013 16:24:39 -0700
Message-ID: <CAPTJ0XH0ryKaxAueYGwgmNS6DcdMQwMPj4OMx=BGWsKQRm_1hg@mail.gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: www-style list <www-style@w3.org>, Ojan Vafai <ojan@chromium.org>
On Wed, Mar 20, 2013 at 4:03 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
> On Wed, Mar 20, 2013 at 1:08 PM, Christian Biesinger
> <cbiesinger@chromium.org> wrote:
>> On Wed, Mar 20, 2013 at 11:50 AM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
>>> On Wed, Mar 20, 2013 at 11:30 AM, Christian Biesinger
>>> <cbiesinger@chromium.org> wrote:
>>>> SECTION 3.1 (justify-self)
>>>> - The spec defines a "baseline" value for justify-self. It is not
>>>> clear to me what that means? Is this just for vertical writing modes,
>>>> or am I missing something?
>>> Basically, yes.  Every box is supposed to generate both a horizontal
>>> and vertical baseline, so that it can be baseline-aligned regardless
>>> of the surrounding writing-mode.
>> Ah. OK, that makes sense. Looking at the code, that shouldn't be too
>> hard to implement, I think.
> For guidance, check out the Flexbox Baselines section
> <http://dev.w3.org/csswg/css3-flexbox/#flex-baselines>, which is very
> precise and explains how to handle cases when there's no appropriate
> baseline in a particular direction.

Does this mean that the synthesized baseline may have to be used also
for justify-content: baseline?

Just to make sure I understand this correctly - in this case:

"First" and "Second" should be aligned, right?

>>>> - The "EXAMPLE 1" would benefit from specifying which justify-self
>>>> value leads to the described behavior, IMO
>>> All of them do - it's just describing how you can combine both margins
>>> and alignment.  It could be written more clearly, definitely.
>> OK, I'll have to think more about that example. By the way, speaking
>> of margins, how does stretch interact with margins? Does it
>> effectively set the margins to zero, or does it only stretch such that
>> there's space for them? I assume it's the latter but I'm not sure.
> Urf, I see we haven't defined "stretch" at all actually.


> "stretch" should act the same way it does in Flexbox - if 'height' is
> "auto", it sets the height such that the margin box exactly fills the
> available space (treating auto margins as zero, unless they've already
> been resolved).  If 'height' isn't auto, is does nothing, and acts
> like 'start'.

(Huh, that behavior surprised me. I expected flexbox to stretch an
explicit-height item, just like flex:1; will flex an explicit-width

I assume that similarly, "center" will center the margin-box, and not
the border-box or content-box.

>>> Note that the head/foot names are still under debate. :/  They're more
>>> traditionally called "before" and "after", but we've been trying to
>>> change them to a better pair.  Any suggestions would be welcome.
>> Maybe top and bottom?
> Nope, they can't be explicitly directional, because they're
> writing-mode specific.  That axis will be horizontal in Japanese.

Hm... good point. I'm out of ideas.

>>>> SECTION 4.1 (justify-content)
>>>> - Do "start" and "end" also apply to flexboxes? The text doesn't say
>>>> that they don't, but that feels weird...
>>> Yes.  Why does it seem weird?  They're just the writing-mode-specific
>>> directions, dependent on whether the element is ltr or rtl.  These are
>>> distinct from flex-start and flex-end - a row-reverse flexbox will
>>> have them opposite.
>> Right, I didn't fully understand that's how they worked. Would it make
>> sense to add a non-normative paragraph to the spec that basically says
>> what you just said?
> The idea is that hopefully the logical directions will become common
> enough that people understand that automatically.  ^_^  But I'll see
> what I can do.

Thanks. By the way, why does justify-content also have "left" and
"right"? Everything else in this spec only uses logical directions

Received on Wednesday, 20 March 2013 23:25:07 UTC

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