Here’s a library from Zhang Yungui called ShapeAnimation-Swift that is based on SwiftGraphics and adds a number of animation extensions to CALAyer and CAShapelayer.

With ShapeAnimation you can easily create different moving animations, drawing path animations, scaling animations, and opacity animations with a nice Swift based syntax.

These three animations from the readme show ShapeAnimation in action:

You can find ShapeAnimation-Swift on Github.