Ios/swift/画像ビューアー

画像ビューアーサンプル

画像urlを指定したサンプル

import UIKit
import SDWebImage
class ImageDetailViewController: UIViewController, UIScrollViewDelegate  {
   @IBOutlet weak var _scrollView: UIScrollView!
   @IBOutlet weak var _imageView: UIImageView!
   internal var imgpath: String! = "https://pbs.twimg.com/media/CnHuxaAWAAI0r3y.jpg"
   override func viewDidLoad() {
       super.viewDidLoad()
       if imgpath.containsString("http://") || imgpath.containsString("https://") {
           let imageURL = NSURL(string: imgpath)
           _imageView.sd_setImageWithURL(imageURL)
       } else {
           _imageView.image = UIImage(named:imgpath)
       }
       // 初期scale
       let myBoundSize: CGSize = UIScreen.mainScreen().bounds.size
       let zoomScaleWidth:CGFloat = CGFloat(_imageView.bounds.size.width) / CGFloat(myBoundSize.width)
       let zoomScaleHeight:CGFloat = CGFloat(_imageView.bounds.size.height) / CGFloat(myBoundSize.height)
       var zoomScale:CGFloat = zoomScaleWidth
       if zoomScaleWidth < zoomScaleHeight {
           zoomScale = zoomScaleHeight
       }
       self._scrollView.delegate = self
       self._scrollView.minimumZoomScale = 0.1
       self._scrollView.maximumZoomScale = 8
       self._scrollView.scrollEnabled = true
       self._scrollView.showsHorizontalScrollIndicator = true
       self._scrollView.showsVerticalScrollIndicator = true
       let doubleTapGesture: UITapGestureRecognizer = UITapGestureRecognizer(target: self
           , action:#selector(self.doubleTap(_:)))
       doubleTapGesture.numberOfTapsRequired = 2
       self._imageView.userInteractionEnabled = true
       self._imageView.addGestureRecognizer(doubleTapGesture)
       self._scrollView.setZoomScale(zoomScale, animated: false)
   }
   override func didReceiveMemoryWarning() {
       super.didReceiveMemoryWarning()
   }
   // ピンチイン・ピンチアウト
   func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
       return self._imageView
   }
   // ダブルタップ
   func doubleTap(gesture: UITapGestureRecognizer) -> Void {
       print(self._scrollView.zoomScale)
       if ( self._scrollView.zoomScale < self._scrollView.maximumZoomScale ) {
           let newScale:CGFloat = self._scrollView.zoomScale * 3
           let zoomRect:CGRect = self.zoomRectForScale(newScale, center: gesture.locationInView(gesture.view))
           self._scrollView.zoomToRect(zoomRect, animated: true)
       } else {
           self._scrollView.setZoomScale(1.0, animated: true)
       }
   }
   // 領域
   func zoomRectForScale(scale:CGFloat, center: CGPoint) -> CGRect{
       var zoomRect: CGRect = CGRect()
       zoomRect.size.height = self._scrollView.frame.size.height / scale
       zoomRect.size.width = self._scrollView.frame.size.width / scale
       zoomRect.origin.x = center.x - zoomRect.size.width / 2.0
       zoomRect.origin.y = center.y - zoomRect.size.height / 2.0
       return zoomRect
   }
}

参考：http://qiita.com/hanoopy/items/7a2c582cd9758e7a3076