title: SwiftUI rotation animation has unexpected translation
body: <p>I'm trying to animate a spinning &quot;busy&quot; image in a SwiftUI <code>View</code> using standard and consistent online tutorials.  The image is square, should be scaled uniformly, and spin forever.</p>
  <p>I can get a spinning image with the following code, however I am seeing unexpected translations with this.  When used in a <code>NavigationView</code> as the <em>initial</em> View the image moves over the course of the animation from top-left to the center of the screen.  When used as the third screen in a <code>NavigationView</code> the image starts roughly in the center of the screen and moves vertically downwards by about half its height over the course of the animation.  Removing the navigationBar and back button reduce the vertical shift to about 20px overall.  Which is interesting.</p>
  <p>Also interestingly, the background stays exactly where I'd expect it to be, in the center of the screen in both cases.  <code>autoreverses</code> behaves as expected and <code>anchor</code>ing the rotation effect seems to have no effect.</p>
  <p>The aim is to have additional controls on the screen (text, Next button etc) but for now I'd be happy with an animation that stays in one place.</p>
  <p>What am I doing wrong?  Any help appreciated!</p>
  <p><a href="https://i.stack.imgur.com/sjtDll.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sjtDll.png" alt="Image illustrating the problem" /></a>The code:</p>
  <pre><code>@State private var isAnimating = false
  
  var body: some View {
      VStack{
          Spacer()
          Image(&quot;FilmCircle&quot;)
              .resizable()
              .scaledToFit()
              .frame(width: 100, height: 100)
              .rotationEffect(Angle(degrees: isAnimating ? 360 : 0), anchor: .center)
              .animation(Animation.linear(duration: 2)
                  .repeatForever(autoreverses: false))
              .onAppear {
                  self.isAnimating = true
              }
              .background(Color.red)
          Spacer()
      }
  }
  </code></pre>