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Flexbox - box orientation

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 16 Apr 2010 17:49:07 -0700
Message-ID: <s2udd0fbad1004161749i6eff959cmf3b0514fe030107e@mail.gmail.com>
To: www-style list <www-style@w3.org>
I'm reading over the current flexbox spec very carefully while writing
my revision, and I notice some oddities in how the
before/after/start/end directions are determined.

First, for a standard horizontal box, start is left and before is top.
 For a standard vertical, start is top and before is left.  This is
all reasonable and fine.  Now, for reverse boxes, *both* directions
reverse - for a horizontal box start is right and before is bottom.
Is this useful?  Naively, I'd assume that you'd only want to reverse
the left/right on a horizontal box, and the top/bottom on a vertical
box.  It seems to me that the flow direction of the axis perpendicular
to the orientation is a completely separate question to the flow
direction of the axis parallel to the orientation.  (I'd like for
there to be a natural mapping between the two, as it would allow a
somewhat simpler model simmering in my head, but I'm not sure if such
a mapping would be natural/useful.)

As well, in the very last paragraph of the Alignment chapter, the
topic of ltr versus rtl comes out of nowhere as affecting the
direction of start/end/before/after edges.  This is not mentioned
anywhere else in the draft, so you could be forgiven for assuming that
text direction plays no part in the determination of the various

What, precisely, are the most useful direction associations here?
What does XUL use?  Do people like what XUL uses?  Is it useful to pay
attention to text direction?

Received on Saturday, 17 April 2010 00:49:59 UTC

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