After Effects 25.4's Quick Offset staggers selected layers, or each
layer's selected keyframes, in the order they were selected: the first
stays, the last moves by the drag and the ones between by equal steps,
landing on subframes.
layer.quickOffset {delta, layers?} moves each layer's start, in and out
point by total * i / (n - 1), worked out once in ticks with integer
arithmetic, so 1 frame over 4 layers gives 0, 1/3, 2/3 and 1 frame
exactly. keys.quickOffset {delta} does the same per layer for the
selected keys, the layers in the order their first key was selected;
every selected key of a layer, across its properties, moves by that
layer's comp-time offset through its start and stretch (reversed too),
keeping values, interpolation, easing and labels. Locked layers are
skipped and at least two layers are needed. With merge and fromStart,
delta is the whole drag and each step starts again from before it, so
the drag is one undo step and a key passed over survives. A delta or a
destination out of the range of times is an error, not a clamped move.
Docs: agents.md; architecture.md notes Quick Offset as the exception to
times snapping to frames.
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