AdjustImageFitInScrollView01.swift

@IBAction func showImg1(_ sender: Any) {
  let image0 = UIImage(named: "Image")
  
  // ここで初期化しておかないとZoomがおかしくなる
  scrollView.zoomScale = 1
  
  imageView.image = image0
  imageView.frame.size = image0!.size
  scrollView.contentSize = image0!.size
        
  adjustImageFitInScrollView()
}