Two issues:
1) For static keyframes (start_value == end_value) AE yields horizontal
orientation (0 tangent). We technically have the same logic in
Skottie, but our value deduplication logic interferes: the two
consecutive equal values are consolidated, and the result ends up
holding the spatial lerp info for the next frame => our hold frames
auto-orient for the beginning of the next keyframe.
Fix: skip value deduplication when spatial lerp is present.
2) The very last keyframe is always static and holds no spatial info.
AE retains the orientation of the previous frame, but Skottie yields
0 tangent.
Fix: the easiest way to accomplish AE semantics is to detect when
we're dealing with the last keyframe, and swap with the previous
keyframe with an adjust weight of 1 (to select the end value). This
produces the same lerp result (because keyframed values are always
contiguous) and also respects the orientation of the prev frame.
TBR=
Change-Id: Id661f7804533e95b747722457489a7ef759572a4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/301176
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
