Invalidate display link

Source/AnimatableImageView.swift

@@ -1,17 +1,15 @@
-import ImageIO
 import Runes
 import UIKit
 
 /// A subclass of `UIImageView` that can be animated using an image name string or raw data.
 public class AnimatableImageView: UIImageView {
   /// An `Animator` instance that holds the frames of a specific image in memory.
-  var animator: Animator?
+  private var animator: Animator?
   /// A display link that keeps calling the `updateFrame` method on every screen refresh.
   private lazy var displayLink: CADisplayLink = CADisplayLink(target: self, selector: Selector("updateFrame"))
 
-  deinit {
-    println("deinit animatable view")
-  }
+  /// The size of the frame cache.
+  public var framePreloadCount = 50
 
   /// A computed property that returns whether the image view is animating.
   public var isAnimatingGIF: Bool {
@@ -32,7 +30,8 @@ public class AnimatableImageView: UIImageView {
   /// :param: data GIF image data.
   public func prepareForAnimation(imageData data: NSData) {
     image = UIImage(data: data)
-    animator = Animator(data: data, size: frame.size, contentMode: contentMode)
+    animator = Animator(data: data, size: frame.size, contentMode: contentMode, framePreloadCount: framePreloadCount)
+    animator?.prepareFrames()
     attachDisplayLink()
   }
 
@@ -74,18 +73,16 @@ public class AnimatableImageView: UIImageView {
   /// Stops the image view animation.
   public func stopAnimatingGIF() {
     displayLink.paused = true
-    cleanup()
   }
 
-  /// Cleanup the animator to reduce memory.
+  /// Invalidate the displayLink so it releases this object.
   public func cleanup() {
-    image = .None
-    animator = .None
+    displayLink.invalidate()
   }
 
-  /// Attaches the dsiplay link.
-  func attachDisplayLink() {
-    displayLink.addToRunLoop(NSRunLoop.mainRunLoop(), forMode: NSRunLoopCommonModes)
+  /// Attaches the display link.
+  private func attachDisplayLink() {
+    displayLink.addToRunLoop(.mainRunLoop(), forMode: NSRunLoopCommonModes)
   }
 }
 

Source/Animator.swift

@@ -3,7 +3,7 @@ import ImageIO
 import Runes
 
 /// Responsible for storing and updating the frames of a `AnimatableImageView` instance via delegation.
-class Animator: NSObject {
+class Animator {
   /// Maximum duration to increment the frame timer with.
   private let maxTimeStep = 1.0
   /// An array of animated frames from a single GIF image.
@@ -13,7 +13,7 @@ class Animator: NSObject {
   /// The content mode to use when resizing
   private let contentMode: UIViewContentMode
   /// Maximum number of frames to load at once
-  private let maxNumberOfFrames = 50
+  private let maxNumberOfFrames: Int
   /// The total number of frames in the GIF.
   private var numberOfFrames = 0
   /// A reference to the original image source.
@@ -37,24 +37,19 @@ class Animator: NSObject {
   ///
   /// :param: data The raw GIF image data.
   /// :param: delegate An `Animatable` delegate.
-  required init(data: NSData, size: CGSize, contentMode: UIViewContentMode) {
+  init(data: NSData, size: CGSize, contentMode: UIViewContentMode, framePreloadCount: Int) {
     let options = [String(kCGImageSourceShouldCache): kCFBooleanFalse]
     imageSource = CGImageSourceCreateWithData(data, options)
     self.size = size
     self.contentMode = contentMode
-    super.init()
-    prepareFrames()
-  }
-
-  deinit {
-    println("deinit animator")
+    maxNumberOfFrames = framePreloadCount
   }
 
   // MARK: - Frames
   /// Loads the frames from an image source, resizes them, then caches them in `animatedFrames`.
-  private func prepareFrames() {
+  func prepareFrames() {
     numberOfFrames = Int(CGImageSourceGetCount(imageSource))
-    let framesToProcess = numberOfFrames > maxNumberOfFrames ? maxNumberOfFrames : numberOfFrames
+    let framesToProcess = min(numberOfFrames, maxNumberOfFrames)
     animatedFrames.reserveCapacity(framesToProcess)
     animatedFrames = reduce(0..<framesToProcess, []) { $0 + pure(prepareFrame($1)) }
   }
@@ -91,8 +86,6 @@ class Animator: NSObject {
   ///
   /// :returns: An optional image at a given frame.
   func updateCurrentFrame(duration: CFTimeInterval) -> Bool {
-    if animatedFrames.count <= 1 { return false }
-
     timeSinceLastFrameChange += min(maxTimeStep, duration)
     var frameDuration = animatedFrames[currentFrameIndex % animatedFrames.count].duration
 
@@ -101,7 +94,7 @@ class Animator: NSObject {
       let lastFrameIndex = currentFrameIndex
       currentFrameIndex = ++currentFrameIndex % numberOfFrames
 
-      // load the next needed frame for progressive loading
+      // Loads the next needed frame for progressive loading
       if animatedFrames.count < numberOfFrames {
         let nextFrameToLoad = (lastFrameIndex + animatedFrames.count) % numberOfFrames
         animatedFrames[lastFrameIndex % animatedFrames.count] = prepareFrame(nextFrameToLoad)