Re: [csswg-drafts] [web-animations-2][css-animations-2] Should animation-trigger-exit-range be constrained to being greater than or equal to animation-trigger-range? (#11910)

The Houdini Task Force just discussed `[web-animations-2][css-animations-2] Should animation-trigger-exit-range be constrained to being greater than or equal to animation-trigger-range?`, and agreed to the following:

* `RESOLVED: the "actual" exit range is the union of the specified enter and exit ranges`

<details><summary>The full IRC log of that discussion</summary>
&lt;TabAtkins> DavidA: this came from our earlier discussion<br>
&lt;TabAtkins> DavidA: the use-cases we can think of, it's useful to have the exit range as a superset of the enter range<br>
&lt;flackr> q+<br>
&lt;TabAtkins> DavidA: it seems like it could just create unexpected beahvior if they're not matching<br>
&lt;TabAtkins> DavidA: so i propose we help authors by enforcing this<br>
&lt;TabAtkins> flackr: >= for animation ranges is hard to calculate<br>
&lt;TabAtkins> flackr: i proposed in the issue that once a trigger enters, it doesn't exit until it's out of both ranges<br>
&lt;TabAtkins> flackr: so you could specify totally separate ranges, it just wouldn't be meaningful<br>
&lt;TabAtkins> flackr: but it would mean we don't have to coerce the ranges so one is greater than the other<br>
&lt;TabAtkins> DavidA: i think my initial concern is if you were still in the entry range but now out of the exit range... that would trigger exit action<br>
&lt;TabAtkins> q+<br>
&lt;TabAtkins> DavidA: so you have separate enter and exit ranges.<br>
&lt;TabAtkins> DavidA: you go into the entry range, you trigger the naimation, but then you're immediateyl outside the exit range<br>
&lt;TabAtkins> DavidA: but your proposal addresses that<br>
&lt;TabAtkins> ack flackr<br>
&lt;TabAtkins> flackr: yeah so if you're in either range, you haven't exited the range<br>
&lt;TabAtkins> ydaniv: one exception is, if you ahve a place where an author specified two ranges that don't overlap, you could be somewhere in the middle...<br>
&lt;TabAtkins> ydaniv: oh, you'd just be exited<br>
&lt;TabAtkins> TabAtkins: i'm fine with either a union of the ranges, or a bounding range<br>
&lt;TabAtkins> flackr: i just didn't want to ahve to compute the bounding range, especially in the computed style<br>
&lt;TabAtkins> TabAtkins: ah, i wasn't thinking of it being reflected into the style<br>
&lt;TabAtkins> flackr: as long as it's not reflected, i'm not opposed to using a bounding range<br>
&lt;TabAtkins> flackr: but i do think eitehr solves the problem<br>
&lt;TabAtkins> flackr: i have a slight preference for the simpler thing<br>
&lt;TabAtkins> TabAtkins: my problem with union is just that if the two ranges are disjoint, you effectively ignore the exit range entirely. but that's weird - in the more common case where you ranges overlap, just not perrfectly, it's indistinguishable, so that's fine.<br>
&lt;TabAtkins> proposed resolution: the "actual" exit range is the union of the specified enter and exit ranges<br>
&lt;TabAtkins> RESOLVED: the "actual" exit range is the union of the specified enter and exit ranges<br>
</details>


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Received on Wednesday, 20 August 2025 14:13:28 UTC