using

ArcMode applied from this keyframe to the next.

Note that arc modes are meant for objects with even dimensions (such as 2D positional values and their variants). Where each value pair is animated as an arc. So, if the object has odd dimensions the last value will always animate linearly.

The order of each value in an object with multiple dimensions is given by the applied vector converter in KeyframesSpec.vectorize.

E.g.: RectToVector assigns its values as [left, top, right, bottom] so the pairs of dimensions animated as arcs are: [left, top] and [right, bottom].