title: How to implement the welcome page animation of appflow
body: <p>Below image is from AppFlow welcome page animation.</p>
  
  <p>Not launch image, this is just part of welcome page , part of.... not all welcome page and I can't show the animation here, so I screen shot some frames of this animation and rearrange here. </p>
  
  <p>I am sure that is not a gif or any image animation, should finished by objc code. Anyone could give me some thread or sample code will be great!</p>
  
  <p>Thanks</p>
  
  <p><img src="https://i.stack.imgur.com/zpiyS.png" alt="AppFlow welcome page animation"></p>