Merge pull request #32 from tungvoduc/develop

Version 1.2.5

DTPhotoViewerController.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = "DTPhotoViewerController"
-  s.version          = "1.2.4"
+  s.version          = "1.2.5"
   s.summary          = "DTPhotoViewerController provides a Facebook-like photo viewer."
   s.platform 	       = :ios, '8.3'
   s.swift_version    = '4.2'

DTPhotoViewerController/Classes/DTImageView.swift

@@ -8,16 +8,7 @@
 
 import UIKit
 
-class DTImageView: UIImageView {
-
-    /*
-    // Only override draw() if you perform custom drawing.
-    // An empty implementation adversely affects performance during animation.
-    override func draw(_ rect: CGRect) {
-        // Drawing code
-    }
-    */
-
+class DTImageView: UIImageView {    
     override var image: UIImage? {
         didSet {
             imageChangeBlock?(image)

DTPhotoViewerController/Classes/DTPhotoCollectionViewCell.swift

@@ -18,6 +18,36 @@ open class DTPhotoCollectionViewCell: UICollectionViewCell {
     public private(set) var scrollView: DTScrollView!
     public private(set) var imageView: UIImageView!
 
+    // default is 1.0
+    open var minimumZoomScale: CGFloat = 1.0 {
+        willSet {
+            if imageView.image == nil {
+                scrollView.minimumZoomScale = 1.0
+            } else {
+                scrollView.minimumZoomScale = newValue
+            }
+        }
+
+        didSet {
+            correctCurrentZoomScaleIfNeeded()
+        }
+    }
+
+    // default is 3.0.
+    open var maximumZoomScale: CGFloat = 3.0 {
+        willSet {
+            if imageView.image == nil {
+                scrollView.maximumZoomScale = 1.0
+            } else {
+                scrollView.maximumZoomScale = newValue
+            }
+        }
+
+        didSet {
+            correctCurrentZoomScaleIfNeeded()
+        }
+    }
+
     weak var delegate: DTPhotoCollectionViewCellDelegate?
 
     public override init(frame: CGRect) {
@@ -34,42 +64,65 @@ open class DTPhotoCollectionViewCell: UICollectionViewCell {
         backgroundColor = UIColor.clear
         isUserInteractionEnabled = true
         scrollView = DTScrollView(frame: CGRect.zero)
-        scrollView.minimumZoomScale = 1.0
-        scrollView.maximumZoomScale = 3.0
+        scrollView.minimumZoomScale = minimumZoomScale
+        scrollView.maximumZoomScale = 1.0 // Not allow zooming when there is no image
 
         let imageView = DTImageView(frame: CGRect.zero)
         // Layout subviews every time getting new image
         imageView.imageChangeBlock = {[weak self](image: UIImage?) -> Void in
             // Update image frame whenever image changes
-            if let strongSelf = self, let _ = image {
-                strongSelf.setNeedsLayout()
+            if let strongSelf = self {
+                if image == nil {
+                    strongSelf.scrollView.minimumZoomScale = 1.0
+                    strongSelf.scrollView.maximumZoomScale = 1.0
+                } else {
+                    strongSelf.scrollView.minimumZoomScale = strongSelf.minimumZoomScale
+                    strongSelf.scrollView.maximumZoomScale = strongSelf.maximumZoomScale
+                    strongSelf.setNeedsLayout()
+                }
+                strongSelf.correctCurrentZoomScaleIfNeeded()
             }
         }
         imageView.contentMode = .scaleAspectFit
         self.imageView = imageView
         scrollView.delegate = self
         addSubview(scrollView)
         scrollView.addSubview(imageView)
+
+        if #available(iOS 11.0, *) {
+            scrollView.contentInsetAdjustmentBehavior = .automatic
+        }
+    }
+
+    private func correctCurrentZoomScaleIfNeeded() {
+        if scrollView.zoomScale < scrollView.minimumZoomScale {
+            scrollView.zoomScale = scrollView.minimumZoomScale
+        }
+
+        if scrollView.zoomScale > scrollView.maximumZoomScale {
+            scrollView.zoomScale = scrollView.maximumZoomScale
+        }
     }
 
     override open func layoutSubviews() {
         super.layoutSubviews()
+        scrollView.zoomScale = 1.0
         scrollView.frame = bounds
 
         //Set the aspect ration of the image
         if let image = imageView.image {
             let size = image.size
-            let horizontalScale = size.width / bounds.width
-            let verticalScale = size.height / bounds.height
+            let horizontalScale = size.width / scrollView.frame.width
+            let verticalScale = size.height / scrollView.frame.height
             let factor = max(horizontalScale, verticalScale)
 
             //Divide the size by the greater of the vertical or horizontal shrinkage factor
             let width = size.width / factor
             let height = size.height / factor
 
             //Then figure out offset to center vertically or horizontally
-            let x = (bounds.width - width) / 2
-            let y = (bounds.height - height) / 2
+            let x = (scrollView.frame.width - width) / 2
+            let y = (scrollView.frame.height - height) / 2
 
             imageView.frame = CGRect(x: x, y: y, width: width, height: height)
         }

DTPhotoViewerController/Classes/DTPhotoViewerController.swift

@@ -344,15 +344,15 @@ open class DTPhotoViewerController: UIViewController {
 
             if (cell.scrollView.zoomScale == cell.scrollView.maximumZoomScale) {
                 // Zoom out
-                cell.scrollView.minimumZoomScale = 1.0
+                cell.minimumZoomScale = 1.0
                 cell.scrollView.setZoomScale(cell.scrollView.minimumZoomScale, animated: true)
 
             } else {
                 let location = gesture.location(in: view)
                 let center = cell.imageView.convert(location, from: view)
 
                 // Zoom in
-                cell.scrollView.minimumZoomScale = 1.0
+                cell.minimumZoomScale = 1.0
                 let rect = zoomRect(for: cell.imageView, withScale: cell.scrollView.maximumZoomScale, withCenter: center)
                 cell.scrollView.zoom(to: rect, animated: true)
             }
@@ -385,7 +385,7 @@ open class DTPhotoViewerController: UIViewController {
         let heightScale = size.height / cell.imageView.bounds.height
         let zoomScale = min(widthScale, heightScale)
 
-        cell.scrollView.maximumZoomScale = zoomScale
+        cell.maximumZoomScale = zoomScale
     }
 
     fileprivate func zoomRect(for imageView: UIImageView, withScale scale: CGFloat, withCenter center: CGPoint) -> CGRect {

DTPhotoViewerController/Classes/DTScrollView.swift

@@ -28,7 +28,7 @@ public class DTScrollView: UIScrollView {
     }
 }
 
-//MARK:
+//MARK: UIGestureRecognizerDelegate
 extension DTScrollView: UIGestureRecognizerDelegate {
     public override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
         if gestureRecognizer == panGestureRecognizer {