I want to use PencilKit to draw perfectly shaped shapes. What should I do?

Using Apple's own photo album, when editing photos, I used the Apple Pencil to draw blurred red paths, keeping and then creating perfect circles. I looked at the API for PencilKit and found that Apple does not provide one. But I want to implement drawing in my application and keep creating the perfect shape. How do I do that?

Shape recognition is a private API. Only Apple's app can use it. My suggestion would be: Check last stroke in the canvasViewDrawingDidChange(), then check with your algorithmen which shape it is, then create a beautiful PKStroke and replace the last stroke.