I implemented a drawing canvas before PencilKit was released. The drawings were stored as PNGData. Is there a way to convert PNGData or a UIImage to a PKDrawing so I can migrate to PencilKit?
There is not an API to convert from image data into a PencilKit drawing. It is possible to synthesize PencilKit drawings using APIs added in iOS 14. For details check out this session: Inspect, modify, and construct PencilKit drawings.