fix imageView alpha animation and add comment

Example/Example/ViewController.swift

@@ -10,15 +10,15 @@ import UIKit
 
 final class ViewController: UIViewController {
 
-    @IBOutlet weak var collectionView: UICollectionView! {
+    @IBOutlet weak private var collectionView: UICollectionView! {
         didSet {
             collectionView.register(UINib(nibName: "ImageCell", bundle: nil), forCellWithReuseIdentifier: "ImageCell")
             collectionView.delegate = self
             collectionView.dataSource = self
         }
     }
 
-    @IBOutlet weak var flowLayout: UICollectionViewFlowLayout! {
+    @IBOutlet weak private var flowLayout: UICollectionViewFlowLayout! {
         didSet {
             flowLayout.scrollDirection = .vertical
             flowLayout.minimumLineSpacing = 1
@@ -51,10 +51,14 @@ extension ViewController: UICollectionViewDelegate {
             return
         }
 
-        let slideLeafs: [SlideLeaf] = images.enumerated().map { SlideLeaf(image: $0.1, title: "Image Title \($0.0)", caption: "Index is \($0.0)") }
+        let slideLeafs: [SlideLeaf] = images.enumerated().map { SlideLeaf(image: $0.1,
+                                                                          title: "Image Title \($0.0)",
+                                                                          caption: "Index is \($0.0)") }
+
         let slideImageViewController = SlideLeafViewController.make(leafs: slideLeafs,
                                                                     startIndex: indexPath.row,
                                                                     fromImageView: selectedCell.imageView)
+
         slideImageViewController.delegate = self
         present(slideImageViewController, animated: true, completion: nil)
     }

Serrata.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.name         = "Serrata"
-  s.version      = "1.0.1"
-  s.summary      = "Slide image viewer library similar to twitter and LINE"
+  s.version      = "1.0.2"
+  s.summary      = "Slide image viewer library similar to twitter and LINE."
 
   s.description  = <<-DESC
                    You can use it simply by passing the necessary information.
@@ -19,13 +19,14 @@ Pod::Spec.new do |s|
   s.author             = { "Takuma Horiuchi" => "horitaku46@gmail.com" }
   s.social_media_url   = "https://twitter.com/horitaku_"
 
-  s.platform     = :ios, "10.0"
-  s.source       = { :git => "https://github.com/horitaku46/Serrata.git", :tag => "#{s.version}" }
-
   s.ios.deployment_target = '10.0'
 
+  s.source       = { :git => "https://github.com/horitaku46/Serrata.git", :tag => "#{s.version}" }
+
   s.source_files = "Serrata/Sources/*.{swift}"
   s.resources = "Serrata/**/*.{storyboard,xib,xcassets}"
 
+  s.requires_arc = true
+
   s.dependency "Kingfisher"
 end

Serrata/Sources/SlideLeaf.swift

@@ -8,20 +8,33 @@
 
 import UIKit
 
-open class SlideLeaf: NSObject {
+public final class SlideLeaf: NSObject {
 
-    open var image: UIImage?
-    open var urlString: String?
+    public var image: UIImage?
+    public var urlString: String?
 
-    open var title: String
-    open var caption: String
+    public var title: String
+    public var caption: String
 
+
+    /// If either title and caption is empty, detailView is not displayed.
+    ///
+    /// - Parameters:
+    ///   - image: To read by a slide.
+    ///   - title: Title of the image.
+    ///   - caption: Caption of the image.
     public init(image: UIImage?, title: String = "", caption: String = "") {
         self.image = image
         self.title = title
         self.caption = caption
     }
 
+    /// If either title and caption is empty, detailView is not displayed.
+    ///
+    /// - Parameters:
+    ///   - urlString: To read by a slide. It is displayed by Kingfisher.
+    ///   - title: Title of the image.
+    ///   - caption: Caption of the image.
     public init(urlString: String?, title: String = "", caption: String = "") {
         self.urlString = urlString;
         self.title = title

Serrata/Sources/SlideLeafCell.swift

@@ -10,7 +10,8 @@ import UIKit
 import Kingfisher
 
 public protocol SlideLeafCellDelegate: class {
-    func slideLeafScrollViewWillBeginDragging(_ scrollView: UIScrollView)
+    func slideLeafScrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?)
+    func slideLeafScrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat)
     func longPressImageView()
 }
 
@@ -60,7 +61,7 @@ open class SlideLeafCell: UICollectionViewCell {
 
     open func configure(slideLeaf: SlideLeaf) {
         if let image = slideLeaf.image {
-            setImage(image)
+            setImage(image, animated: false)
 
         } else if let url = slideLeaf.urlString {
             activityIndicatorView.startAnimating()
@@ -70,7 +71,7 @@ open class SlideLeafCell: UICollectionViewCell {
                 guard let me = self, let image = image else { return }
                 me.activityIndicatorView.isHidden = true
                 me.activityIndicatorView.stopAnimating()
-                me.setImage(image)
+                me.setImage(image, animated: true)
             }
         }
     }
@@ -89,13 +90,17 @@ open class SlideLeafCell: UICollectionViewCell {
         scrollView.setZoomScale(1, animated: false)
     }
 
-    private func setImage(_ image: UIImage) {
+    private func setImage(_ image: UIImage, animated: Bool) {
         imageView.image = image
         calcImageViewFrame(image)
         scrollView.addSubview(imageView)
-
-        UIView.animate(withDuration: 0.2) {
-            self.imageView.alpha = 1
+
+        if animated {
+            UIView.animate(withDuration: 0.2) {
+                self.imageView.alpha = 1
+            }
+        } else {
+            imageView.alpha = 1
         }
     }
 
@@ -154,7 +159,11 @@ extension SlideLeafCell: UIScrollViewDelegate {
         updateImageViewToCenter()
     }
 
-    open func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
-        delegate?.slideLeafScrollViewWillBeginDragging(scrollView)
+    open func scrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) {
+        delegate?.slideLeafScrollViewWillBeginZooming(scrollView, with: view)
+    }
+
+    open func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {
+        delegate?.slideLeafScrollViewDidEndZooming(scrollView, with: view, atScale: scale)
     }
 }

Serrata/Sources/SlideLeafViewController.swift

@@ -15,11 +15,11 @@ fileprivate enum SlideLeafConst {
 
 @objc public protocol SlideLeafViewControllerDelegate: class {
     func tapImageDetailView(slideLeaf: SlideLeaf, pageIndex: Int)
-    @objc func longPressImageView(slideLeafViewController: SlideLeafViewController, slideLeaf: SlideLeaf, pageIndex: Int)
-    @objc func slideLeafViewControllerDismissed(slideLeaf: SlideLeaf, pageIndex: Int)
+    @objc optional func longPressImageView(slideLeafViewController: SlideLeafViewController, slideLeaf: SlideLeaf, pageIndex: Int)
+    @objc optional func slideLeafViewControllerDismissed(slideLeaf: SlideLeaf, pageIndex: Int)
 }
 
- open class SlideLeafViewController: UIViewController {
+open class SlideLeafViewController: UIViewController {
 
     open override var prefersStatusBarHidden: Bool {
         return true
@@ -112,6 +112,14 @@ fileprivate enum SlideLeafConst {
     private var selectedCell = SlideLeafCell()
     private var isDecideDissmiss = false
 
+
+    /// This method generates SlideLeafViewController.
+    ///
+    /// - Parameters:
+    ///   - leafs: It is array to display it by a slide.
+    ///   - startIndex: It is for initial indication based on array of leafs.
+    ///   - fromImageView: ImageView of the origin of transition. In the case of nil, CrossDissolve.
+    /// - Returns: Instance of SlideLeafViewController.
     open class func make(leafs: [SlideLeaf], startIndex: Int = 0, fromImageView: UIImageView? = nil) -> SlideLeafViewController {
         let viewController = UIStoryboard(name: "SlideLeafViewController", bundle: Bundle(for: SlideLeafViewController.self))
             .instantiateViewController(withIdentifier: "SlideLeafViewController") as! SlideLeafViewController
@@ -185,7 +193,7 @@ fileprivate enum SlideLeafConst {
                 dismiss(animated: true) {
                     if self.isDecideDissmiss {
                         let leaf = self.slideLeafs[self.pageIndex]
-                        self.delegate?.slideLeafViewControllerDismissed(slideLeaf: leaf, pageIndex: self.pageIndex)
+                        self.delegate?.slideLeafViewControllerDismissed!(slideLeaf: leaf, pageIndex: self.pageIndex)
                     }
                 }
             }
@@ -271,13 +279,19 @@ extension SlideLeafViewController: UIScrollViewDelegate {
 
 extension SlideLeafViewController: SlideLeafCellDelegate {
 
-    open func slideLeafScrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+    open func slideLeafScrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) {
         imageDetailView.fadeOut()
     }
 
+    public func slideLeafScrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {
+        if scale == 1 {
+            imageDetailView.fadeIn()
+        }
+    }
+
     open func longPressImageView() {
         let leaf = slideLeafs[pageIndex]
-        delegate?.longPressImageView(slideLeafViewController: self, slideLeaf: leaf, pageIndex: pageIndex)
+        delegate?.longPressImageView!(slideLeafViewController: self, slideLeaf: leaf, pageIndex: pageIndex)
     }
 }
 
@@ -286,7 +300,7 @@ extension SlideLeafViewController: ImageDetailViewDelegate {
     open func tapCloseButton() {
         dismiss(animated: true) {
             let leaf = self.slideLeafs[self.pageIndex]
-            self.delegate?.slideLeafViewControllerDismissed(slideLeaf: leaf, pageIndex: self.pageIndex)
+            self.delegate?.slideLeafViewControllerDismissed!(slideLeaf: leaf, pageIndex: self.pageIndex)
         }
     }