Description
As we're adding more features or types to animation triggers #12314 and as we've mostly decided that triggers should be an independent thing controlling the playback of an animation #12119, I think that we should create triggers in a similar way to view or scroll timelines.
TLDR; I propose we have new prefixes that independent from the animation-* longhands for creating named triggers, e.g. timeline-trigger-* combined with a dashed-ident name that can
5C12
be referenced from the animation-trigger property on an animation (similar to referencing an animation-timeline).
As we're adding all of these features, they each come with a long set of properties. We also expect for event triggers that the source of the events may be on a completely different element. As such, I think these should be set up in a manner similar to view or scroll timelines and referenced from the animations which want to associate with them.
We can of course also have a convenience function for creating anonymous triggers directly from the animation-trigger property but I think it may be confusing and inconvenient to add a bunch of animation-trigger-* longhand properties when triggers, like timelines, are not inherently associated with or part of the definition of an animation and which properties they have depends on the type of trigger.