Chart (modified in place).
Line index.
Event layer index (0 = first layer).
Fractional beat where the event starts.
Fractional beat where the event ends.
Rotation in degrees at startBeat.
Rotation in degrees at endBeat.
RPE easing type 1–28 (default: 1 = linear).
Add a rotation event to a specific event layer of a line.
Rotation values are in degrees (clockwise positive in RPE).