[css-conditional-5] Disambiguate scrollable/direction when along axis/towards edge

[noamr]

The current explainer defines the following properties:

scrollable: none | top | right | bottom | left | block-start | inline-start | block-end | inline-end | x | y | block | inline;
direction: none | top | right | bottom | left | block-start | inline-start | block-end | inline-end | x | y | block | inline;

This is a bit ambiguous in terms of readability. For example "block" means "along the block axis", it's not exactly a direction.
Also it's not clear that "direction" means "currently scrolling".

Proposing instead something along the lines of:

scrolling-along: none | x | y | block | inline;
scrollable-along: none | x | y | block | inline;
scrolling-towards: none | top | right | bottom | left | block-start | inline-start | block-end | inline-end;
scrollable-towards: none | top | right | bottom | left | block-start | inline-start | block-end | inline-end;

We can also use the words axis and direction instead of along and towards.
Alternatively, change direction to scrolling so that at least that ambiguity is sorted.

[noamr]

Having discussed this internally, suggesting to change the name of direction to something that represents the fact that it's the "recent scrolling direction" (unlike scrollable), but keeping it as two things (the first being scrollable) and not four.

It can be: recent, recent-direction, last, or last-direction.
Having the word direction in there hints that this is "the last/recent scroll state".

[fantasai]

There was some discussion on this in #6400 particularly #6400 (comment) and #6400 (comment) that maybe got lost along the way.

My suggestion would be:

scrollable: none | x | y | block | inline
scrolling: none | up | down | left | right | x-forward | x-backward | y-forward | y-backward | inline-forward | inline-backward | block-forward | block-backward

or alternatively

scrollable: none | x | y | block | inline
scrolling: none | up | down | left | right | [ x | y | block | inline ] && [ forward | backward ]

If we need to distinguish the most recent direction vs the currently active direction, maybe use scrolling vs scrolled.

[css-meeting-bot]

The CSS Working Group just discussed [css-conditional-5] Disambiguate scrollable/direction when along axis/towards edge, and agreed to the following:

• RESOLVED: Change 'direction' to 'scrolled', discuss keywords later

The full IRC log of that discussion

<fantasai> noamr: We're currently using `scrollable` to say having the ability to scroll vertically or horizontally
<Rossen3> ack lea
<Zakim> lea, you wanted to react to fantasai
<fantasai> noamr: and then we are using `direction` for most recent scrolling direction
<fantasai> noamr: It felt that something was not totally finished in the naming
<fantasai> noamr: There's a few suggestions in the issue
<fantasai> noamr: Not super opinionated, but needs some work
<noamr> fantasai: miriam has suggested "scrolling" and "scrollable"; I think it kind of works
<noamr> fantasai: if it's now vs. recent if can be scrolling/scrolled
<moonira> q+
<noamr> fantasai: keywords for the scrolling direction can also use forward/backwards rather than x/y, or up/down/left/right rather than edges
<Rossen3> ack fantasai
<Rossen3> ack moonira
<fantasai> moonira: Just saw your comment, you mentioned scrollable as having none | x | y | block | inline
<fantasai> moonira: Do you mean changing those values as well, and remove values like top/bottom/etc?
<fantasai> fantasai: Wasn't clear to me from noam's comment about whether we were including the sides or not
<fantasai> moonira: scrollable is shipped, so prefer not to change that one, but for direction sounds great
<fantasai> moonira: If everyone is ok with Elika's proposal, can we decide to go with `scrolled` for last direction and use the keywords from that proposal?
<flackr> fantasai's proposal sgtm
<fantasai> moonira: Just want to make some progress here
<noamr> +1 to scrolled
<fantasai> Rossen3: Any additional opinions, or should we go with `scrolled` for last direction and keywords from the proposal?
<JoshT> +1
<Rossen3> ack fantasai
<fantasai> 'x-forward' vs 'x forward'
<fantasai> which style do we want?
<noamr> fantasai: there were independent proposals; up/down/left/right doesn't embed a direction but back/forward doesn't
<fantasai> flackr: what's that?
<fantasai> fantasai: physical axis with logical direction
<fantasai> fantasai: we do this for position-area, background-position
<flackr> I like hyphenated because up/right/down/left already have axis in them
<noamr> fantasai: the q is whether to have it space separated or hyphenated
<fantasai> fantasai: question is whether to use precombined hyphenated or combinable space-separated
<noamr> q+
<fantasai> miriam: Haven't thought through it, but prefer space-separated combinable
<djmarland> What would "left backward" do?
<fantasai> noamr: I suggest we resolve on `scrolled` as the descriptor, and we can ponder the additional keywords
<Rossen3> ack noamr
<fantasai> PROPOSED: Change 'direction' to 'scrolled', discuss keywords later
<fantasai> RESOLVED: Change 'direction' to 'scrolled', discuss keywords later
<fantasai> fantasai: Ok, let's come back to that though. It's confusing about whether scrolling towards or from the specified edge, so I think directional keywords would be better (in one form or another)