W3C home > Mailing lists > Public > www-style@w3.org > April 2013

Re: [css-align] logical alignment and bidi / orthogonal flows

From: Christian Biesinger <cbiesinger@google.com>
Date: Fri, 12 Apr 2013 11:37:08 -0700
Message-ID: <CAPTJ0XH0Fjs-CGdES0wWahO0fdp7ddRRuWmfHfJtb8VnHp3tWA@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: "www-style@w3.org" <www-style@w3.org>
I agree that this seems like a very reasonable way to specify these
properties. Since children get positioned by the parent, this seems
like the most straightforward way to implement them too.


On Thu, Apr 11, 2013 at 1:00 PM, fantasai <fantasai.lists@inkedblade.net> wrote:
> Tab and I were discussing the interpretation of 'start' and 'end' on
> justify-self vs. justify-content vs. justify-items and came up with
> an issue wrt what happens when the container and the child have
> different writing modes.
> For example, imagine an RTL item inside a flexbox or grid that is LTR.
> If 'align-items' is set to 'start' on the flexbox, all LTR items will
> align to the left edge, because their 'align-self' values look up to
> their parent's 'align-items' value. For the RTL item, it will also
> acquire 'start' alignment: the issue is whether it will align with
> all the items on the left side, or whether it will follow its own
> directionality and align to the right.
> Our conclusion is that these keywords should be container-focussed,
> that is, justify-content/justify-items resolve against the element
> itself, and justify-self resolves against the parent.
> This keeps the values of justify-items (on the parent) and justify-self
> (on the child), which both control the child, consistent. (It's also
> consistent with how logical properties work in orthogonal flows.)
> Flexbox avoids this issue by using 'flex-start' and 'flex-end', which
> are defined to be relative to the 'flex-flow'. Matching up 'start'
> and 'end' in this way is also consistent with that container-focussed
> approach as well.
> It does feel a little weird for the more document-centric uses of
> block layout, but it makes a lot of sense for the layout-centric Grid
> and Flexbox layout models.
> So this is mostly a heads-up, and a request for feedback if anyone
> has concerns or comments. We'll be updating CSS3 Box Alignment
> to clarify this point accordingly.
> We're also proposing to add 'self-start' and 'self-end' values to
> the align/justify-self properties, so that if an author does want
> to set alignment relative to the item's own writing mode, it can
> be done as well.
> ~fantasai and TJ
Received on Monday, 15 April 2013 08:47:56 UTC

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