Added ability to add a fallback image for all ImageSlideshowItem's

ImageSlideshow/Classes/Core/ImageSlideshow.swift

@@ -28,7 +28,7 @@ public protocol ImageSlideshowDelegate: class {
     @objc optional func imageSlideshowDidEndDecelerating(_ imageSlideshow: ImageSlideshow)
 }
 
-/** 
+/**
     Used to represent position of the Page Control
     - hidden: Page Control is hidden
     - insideScrollView: Page Control is inside image slideshow
@@ -145,6 +145,10 @@ open class ImageSlideshow: UIView {
         }
     }
 
+    /// Optional fallbackImage for each InputSource
+    open var fallbackImage: ImageSource?
+
+
     /// Current scroll view page. This may differ from `currentPage` as circular slider has two more dummy pages at indexes 0 and n-1 to provide fluent scrolling between first and last item.
     open fileprivate(set) var scrollViewPage: Int = 0
 
@@ -207,6 +211,9 @@ open class ImageSlideshow: UIView {
         }
     }
 
+    // Fallback content mode for fallbackImage
+    open var fallbackScaleMode: UIView.ContentMode = .scaleAspectFit
+
     fileprivate var slideshowTimer: Timer?
     fileprivate var scrollViewImages = [InputSource]()
     fileprivate var isAnimating: Bool = false
@@ -283,7 +290,8 @@ open class ImageSlideshow: UIView {
             pageIndicatorView.isHidden = images.count < 2
 
             var edgeInsets: UIEdgeInsets = UIEdgeInsets.zero
-            if #available(iOS 11.0, *) {
+            if #available(iOS 11.0, *),
+                pageIndicator?.respectSafeAreaInsets ?? true {
                 edgeInsets = safeAreaInsets
             }
 
@@ -320,7 +328,7 @@ open class ImageSlideshow: UIView {
 
         var i = 0
         for image in scrollViewImages {
-            let item = ImageSlideshowItem(image: image, zoomEnabled: zoomEnabled, activityIndicator: activityIndicator?.create(), maximumScale: maximumScale)
+            let item = ImageSlideshowItem(image: image, zoomEnabled: zoomEnabled, activityIndicator: activityIndicator?.create(), maximumScale: maximumScale, fallbackImage: fallbackImage, fallbackScaleMode: fallbackScaleMode)
             item.imageView.contentMode = contentScaleMode
             slideshowItems.append(item)
             scrollView.addSubview(item)

ImageSlideshow/Classes/Core/ImageSlideshowItem.swift

@@ -20,6 +20,12 @@ open class ImageSlideshowItem: UIScrollView, UIScrollViewDelegate {
     /// Input Source for the item
     public let image: InputSource
 
+    /// Fallback Input Source for the item
+    public let fallbackImage: InputSource?
+
+    /// Scale mode for fallback input source
+    public let fallbackScaleMode: UIView.ContentMode
+
     /// Guesture recognizer to detect double tap to zoom
     open var gestureRecognizer: UITapGestureRecognizer?
 
@@ -52,12 +58,16 @@ open class ImageSlideshowItem: UIScrollView, UIScrollViewDelegate {
         Initializes a new ImageSlideshowItem
         - parameter image: Input Source to load the image
         - parameter zoomEnabled: holds if it should be possible to zoom-in the image
+        - parameter fallbackImage: A fallback image to display if image is unavailable
+        - parameter fallbackScaleMode: The fallback image scale mode
     */
-    init(image: InputSource, zoomEnabled: Bool, activityIndicator: ActivityIndicatorView? = nil, maximumScale: CGFloat = 2.0) {
+    init(image: InputSource, zoomEnabled: Bool, activityIndicator: ActivityIndicatorView? = nil, maximumScale: CGFloat = 2.0, fallbackImage: InputSource? = nil, fallbackScaleMode: UIViewContentMode = .scaleAspectFit) {
         self.zoomEnabled = zoomEnabled
         self.image = image
         self.activityIndicator = activityIndicator
         self.maximumScale = maximumScale
+        self.fallbackImage = fallbackImage
+        self.fallbackScaleMode = fallbackScaleMode
 
         super.init(frame: CGRect.null)
 
@@ -135,7 +145,8 @@ open class ImageSlideshowItem: UIScrollView, UIScrollViewDelegate {
 
     /// Request to load Image Source to Image View
     public func loadImage() {
-        if self.imageView.image == nil && !isLoading {
+        if (self.imageView.image == nil || self.loadFailed) && !isLoading {
+            self.imageView.image = nil
             isLoading = true
             imageReleased = false
             activityIndicator?.show()
@@ -150,6 +161,17 @@ open class ImageSlideshowItem: UIScrollView, UIScrollViewDelegate {
                 self?.loadFailed = image == nil
                 self?.isLoading = false
 
+                if (self?.loadFailed ?? false) && self?.fallbackImage != nil {
+                    if let imageView = self?.imageView {
+                        self?.fallbackImage?.load(to: imageView) { [weak self] fallbackImage in
+                            imageView.image = (self?.imageReleased ?? false) ? nil : fallbackImage
+                            if let scaleMode = self?.fallbackScaleMode {
+                                imageView.contentMode = scaleMode
+                            }
+                        }
+                    }
+                }
+
                 self?.setNeedsLayout()
             }
         }

ImageSlideshow/Classes/Core/PageIndicator.swift

@@ -17,6 +17,9 @@ public protocol PageIndicatorView: class {
 
     /// Total number of pages of the page indicator
     var numberOfPages: Int { get set}
+
+    /// Bool indicating if the page indicator view should respect safe area insets
+    var respectSafeAreaInsets: Bool { get }
 }
 
 extension UIPageControl: PageIndicatorView {
@@ -33,6 +36,10 @@ extension UIPageControl: PageIndicatorView {
         }
     }
 
+    public var respectSafeAreaInsets: Bool {
+        return true
+    }
+
     open override func sizeToFit() {
         var frame = self.frame
         frame.size = size(forNumberOfPages: numberOfPages)
@@ -59,6 +66,10 @@ public class LabelPageIndicator: UILabel, PageIndicatorView {
         }
     }
 
+    public var respectSafeAreaInsets: Bool {
+        return true
+    }
+
     public override init(frame: CGRect) {
         super.init(frame: frame)
         initialize()