title: iOS - Animating background issue
body: <p>I am trying to animate few elements on a screen, here's the code: </p>
  
  <pre><code>  private func setupAnimations() {
  
      self.emailAddress.alpha = 0
      self.fullName.alpha = 0
      self.password.alpha = 0
      self.confirmPassword.alpha = 0
      self.signUp.alpha = 0
      self.fullName.leftView?.alpha = 0
      self.emailAddress.leftView?.alpha = 0
      self.password.leftView?.alpha = 0
      self.confirmPassword.leftView?.alpha = 0
  
      self.emailAddress.center.x += self.view.bounds.width-10
      self.fullName.center.x -= self.view.bounds.width-10
      self.password.center.x -= self.view.bounds.width-10
      self.confirmPassword.center.x += self.view.bounds.width-10
      self.signUp.center.y += self.view.bounds.height/2
  
      UIView.animate(withDuration: 1.7, delay: 0.2, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [.allowUserInteraction,.curveEaseInOut], animations: {
  
          self.emailAddress.alpha = 1
          self.emailAddress.center.x -= self.view.bounds.width-10
          self.view.layoutIfNeeded()
  
      }, completion: {(completed) in
  
          if completed {
  
              UIView.animate(withDuration: 1, animations: {
                  self.fullName.leftView?.alpha = 1
                  self.emailAddress.leftView?.alpha = 1
                  self.password.leftView?.alpha = 1
                  self.confirmPassword.leftView?.alpha = 1
              })
  
          }
  
      })
  
      UIView.animate(withDuration: 1.7, delay: 0, usingSpringWithDamping: 0.7, initialSpringVelocity: 0.5, options: [.allowUserInteraction,.curveEaseInOut], animations: {
  
          self.fullName.alpha = 1
          self.fullName.center.x += self.view.bounds.width-10
          self.view.layoutIfNeeded()
  
      }, completion: {(completed) in
  
          if completed {
  
              UIView.animate(withDuration: 1, animations: {
                  self.fullName.leftView?.alpha = 1
                  self.emailAddress.leftView?.alpha = 1
                  self.password.leftView?.alpha = 1
                  self.confirmPassword.leftView?.alpha = 1
              })
  
          }
  
      })
  </code></pre>
  
  <p>And so on.. you get the idea - Im setting the alpha to 0 and center x to be off screen, and animate it "arriving" on the screen, its being called in viewDidLoad(). Everything worked out for a month, but recently I have checked this and here's the problem:</p>
  
  <p>video link: <a href="https://streamable.com/lhqvu" rel="nofollow noreferrer">https://streamable.com/lhqvu</a></p>
  
  <p>The background, which is an UIImage in a superview is also being animated, making the superview (red background) being seen.</p>
  
  <p><img src="https://i.stack.imgur.com/7Pcok.jpg" alt="screenshot of hierarchy and constraints"></p>
  
  <p>Any help would be appreciated. Thank you in advance.</p>