Get the values in order to plot animation curves for any SwiftUI animation

easingcurve.swift

// created Michael Katz November 2019
// MIT licensed

import SwiftUI

struct ContentView: View {
  @State var start: Bool = false

  var animationToExplore: Animation  {
    // replace this animation with the animation you want to graph
    return Animation.spring().speed(1)
  }

  var body: some View {
    VStack {
      Button(action: {
        withAnimation(self.animationToExplore) {
          self.start.toggle()
        }

      }) {
        Text("Tap Here")
      }
      AnimatedView(start: start)
        .frame(width: 30, height: 30)
        .offset(x: start ? 0 : 100, y: 0) // do this just to see something so you know it's working
        .animation(animationToExplore)
    }
  }
}

struct ContentView_Previews: PreviewProvider {
  static var previews: some View {
    ContentView()
  }
}

struct AnimatedView: Shape {
  var start: Bool
  private var animatedValue: Double

  var animatableData: Double {
    get { return animatedValue }
    set { animatedValue = newValue }
  }

  init(start: Bool) {
    self.start = start
    self.animatedValue = start ? 1 : 0
  }

  func path(in rect: CGRect) -> Path {
    print(animatedValue) // put the values in the console
    return Path(ellipseIn: rect)
  }
}