[csswg-drafts] [css-align] the `start` keyword should be unambiguously defined as the inline-start / block-start side. (#6186)

dholbert has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-align] the `start` keyword should be unambiguously defined as the inline-start / block-start side. ==
In https://github.com/web-platform-tests/wpt/issues/28378 , it came to light that there's some ambiguity in the alignment spec about what the `start` keyword actually means, in the context of a flexbox.  (Similar for `end`.)  I think the spec *intends* to define it unambiguously, and it sort-of does if you have enough additional context, but it's worded such that a reader could reasonably come away with the wrong interpretation.

It's defined as follows, in css-align section 4.1:
> start (self, content)
>    Aligns the alignment subject to be flush with the alignment container’s start edge in the appropriate axis. 

https://drafts.csswg.org/css-align/#valdef-self-position-start

Concerns:
 (1) the spec is defining "start" in terms of itself ("the start edge"), which isn't especially illuminating. :)
 (2) for a flexbox, the current spec text definition could be misinterpreted as meaning "the main-start or cross-start edge" (if you interpret "the appropriate axis" as e.g. "the main axis", and then reasonably infer that "the start side" of that axis is the main-start side).  This isn't the spec's intended meaning (otherwise `start` and `flex-start` would be identical in a flexbox), but that's not unambiguously clear right now.

SUGGESTION: This probably wants s/start edge/block-start edge or inline-start edge/, or a similar clarification to make it clear (since the terms "inline-start" and "block-start" are unambiguously defined, and that makes it clear that this isn't talking about e.g. the main-start/cross-start edges.)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6186 using your GitHub account


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Received on Tuesday, 6 April 2021 22:23:31 UTC