Remove preloading functionality and clean up

- Closes #6

Demo/demo/classes/ViewController.swift

@@ -8,8 +8,10 @@ class ViewController: UIViewController {
   
   override func viewDidLoad() {
     super.viewDidLoad()
-    imageView.setAnimatableImage(named: "mugen.gif")
+    if let image = AnimatedImage.animatedImageWithName("mugen.gif") {
-    imageView.startAnimatingGIF()
+      imageView.setAnimatedImage(image)
+      imageView.startAnimatingGIF()
+    }
     UIApplication.sharedApplication().setStatusBarStyle(.LightContent, animated: false)
   }
 

Gifu.xcodeproj/project.pbxproj

@@ -7,19 +7,25 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
-		00B8C75E1A364DCE00C188E7 /* Gifu.swift in Sources */ = {isa = PBXBuildFile; fileRef = 00B8C75B1A364DCE00C188E7 /* Gifu.swift */; };
+		00B8C75E1A364DCE00C188E7 /* AnimatedImage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 00B8C75B1A364DCE00C188E7 /* AnimatedImage.swift */; };
 		00B8C75F1A364DCE00C188E7 /* ImageSourceHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 00B8C75C1A364DCE00C188E7 /* ImageSourceHelpers.swift */; };
 		00B8C7601A364DCE00C188E7 /* UIImageView+Gifu.swift in Sources */ = {isa = PBXBuildFile; fileRef = 00B8C75D1A364DCE00C188E7 /* UIImageView+Gifu.swift */; };
 		00B8C7961A3650EE00C188E7 /* Gifu.h in Headers */ = {isa = PBXBuildFile; fileRef = 00B8C7951A3650EE00C188E7 /* Gifu.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		EAF49C7F1A3A4DE000B395DF /* UIImageExtension.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAF49C7E1A3A4DE000B395DF /* UIImageExtension.swift */; };
+		EAF49C811A3A4FAA00B395DF /* Functional.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAF49C801A3A4FAA00B395DF /* Functional.swift */; };
+		EAF49CB11A3B6EEB00B395DF /* AnimatedFrame.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAF49CB01A3B6EEB00B395DF /* AnimatedFrame.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
 		00B8C73E1A364DA400C188E7 /* Gifu.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Gifu.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		00B8C7421A364DA400C188E7 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; name = Info.plist; path = ../Source/Info.plist; sourceTree = "<group>"; };
-		00B8C75B1A364DCE00C188E7 /* Gifu.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Gifu.swift; sourceTree = "<group>"; };
+		00B8C75B1A364DCE00C188E7 /* AnimatedImage.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AnimatedImage.swift; sourceTree = "<group>"; };
 		00B8C75C1A364DCE00C188E7 /* ImageSourceHelpers.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageSourceHelpers.swift; sourceTree = "<group>"; };
 		00B8C75D1A364DCE00C188E7 /* UIImageView+Gifu.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "UIImageView+Gifu.swift"; sourceTree = "<group>"; };
 		00B8C7951A3650EE00C188E7 /* Gifu.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Gifu.h; sourceTree = "<group>"; };
+		EAF49C7E1A3A4DE000B395DF /* UIImageExtension.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = UIImageExtension.swift; sourceTree = "<group>"; };
+		EAF49C801A3A4FAA00B395DF /* Functional.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Functional.swift; sourceTree = "<group>"; };
+		EAF49CB01A3B6EEB00B395DF /* AnimatedFrame.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AnimatedFrame.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -63,9 +69,12 @@
 			isa = PBXGroup;
 			children = (
 				00B8C7951A3650EE00C188E7 /* Gifu.h */,
-				00B8C75B1A364DCE00C188E7 /* Gifu.swift */,
+				00B8C75B1A364DCE00C188E7 /* AnimatedImage.swift */,
 				00B8C75C1A364DCE00C188E7 /* ImageSourceHelpers.swift */,
 				00B8C75D1A364DCE00C188E7 /* UIImageView+Gifu.swift */,
+				EAF49C7E1A3A4DE000B395DF /* UIImageExtension.swift */,
+				EAF49C801A3A4FAA00B395DF /* Functional.swift */,
+				EAF49CB01A3B6EEB00B395DF /* AnimatedFrame.swift */,
 			);
 			path = Source;
 			sourceTree = "<group>";
@@ -148,9 +157,12 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				EAF49CB11A3B6EEB00B395DF /* AnimatedFrame.swift in Sources */,
 				00B8C7601A364DCE00C188E7 /* UIImageView+Gifu.swift in Sources */,
 				00B8C75F1A364DCE00C188E7 /* ImageSourceHelpers.swift in Sources */,
-				00B8C75E1A364DCE00C188E7 /* Gifu.swift in Sources */,
+				EAF49C811A3A4FAA00B395DF /* Functional.swift in Sources */,
+				00B8C75E1A364DCE00C188E7 /* AnimatedImage.swift in Sources */,
+				EAF49C7F1A3A4DE000B395DF /* UIImageExtension.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

Source/AnimatedFrame.swift

@@ -0,0 +1,4 @@
+struct AnimatedFrame {
+  let image: UIImage?
+  let duration: NSTimeInterval
+}

Source/AnimatedImage.swift

@@ -0,0 +1,116 @@
+import UIKit
+import ImageIO
+
+public class AnimatedImage: UIImage {
+  // MARK: - Constants
+  let maxTimeStep = 1.0
+
+  // MARK: - Public Properties
+  var delegate: UIImageView?
+  var animatedFrames = [AnimatedFrame]()
+  var totalDuration: NSTimeInterval = 0.0
+
+  // MARK: - Private Properties
+  private lazy var displayLink: CADisplayLink = CADisplayLink(target: self, selector: "updateCurrentFrame")
+  private var currentFrameIndex = 0
+  private var timeSinceLastFrameChange: NSTimeInterval = 0.0
+
+  // MARK: - Computed Properties
+  var currentFrame: UIImage? {
+    return frameAtIndex(currentFrameIndex)
+  }
+
+  private var isAnimated: Bool {
+    return totalDuration != 0.0
+  }
+
+  // MARK: - Initializers
+  required public init(coder aDecoder: NSCoder) {
+    super.init(coder: aDecoder)
+  }
+
+  public override convenience init(data: NSData) {
+    self.init(data: data, size: CGSizeZero)
+  }
+
+  required public init(data: NSData, size: CGSize) {
+    super.init()
+
+    let imageSource = CGImageSourceCreateWithData(data, nil)
+    attachDisplayLink()
+    curry(prepareFrames) <^> imageSource <*> size
+    pauseAnimation()
+  }
+
+  // MARK: - Factories
+  public class func animatedImageWithName(name: String) -> AnimatedImage? {
+    let path = NSBundle.mainBundle().bundlePath.stringByAppendingPathComponent(name)
+    return animatedImageWithData <^> NSData(contentsOfFile: path)
+  }
+
+  public class func animatedImageWithData(data: NSData) -> AnimatedImage {
+    let size = UIImage.sizeForImageData(data) ?? CGSizeZero
+    return self(data: data, size: size)
+  }
+
+  public class func animatedImageWithName(name: String, size: CGSize) -> AnimatedImage? {
+    let path = NSBundle.mainBundle().bundlePath.stringByAppendingPathComponent(name)
+    return curry(animatedImageWithData) <^> NSData(contentsOfFile: path) <*> size
+  }
+
+  public class func animatedImageWithData(data: NSData, size: CGSize) -> AnimatedImage {
+    return self(data: data, size: size)
+  }
+
+  // MARK: - Display Link Helpers
+  func attachDisplayLink() {
+    displayLink.addToRunLoop(NSRunLoop.mainRunLoop(), forMode: NSRunLoopCommonModes)
+  }
+
+  // MARK: - Frame Methods
+  private func prepareFrames(imageSource: CGImageSourceRef, size: CGSize) {
+    let numberOfFrames = Int(CGImageSourceGetCount(imageSource))
+    animatedFrames.reserveCapacity(numberOfFrames)
+
+    (animatedFrames, totalDuration) = reduce(0..<numberOfFrames, ([AnimatedFrame](), 0.0)) { accum, index in
+      let frameDuration = CGImageSourceGIFFrameDuration(imageSource, index)
+      let frameImageRef = CGImageSourceCreateImageAtIndex(imageSource, UInt(index), nil)
+      let frame = UIImage(CGImage: frameImageRef)?.resize(size)
+      let animatedFrame = AnimatedFrame(image: frame, duration: frameDuration)
+      return (accum.0 + [animatedFrame], accum.1 + frameDuration)
+    }
+  }
+
+  func frameAtIndex(index: Int) -> UIImage? {
+    if index >= animatedFrames.count { return .None }
+    return animatedFrames[index].image
+  }
+
+  func updateCurrentFrame() {
+    if !isAnimated { return }
+
+    timeSinceLastFrameChange += min(maxTimeStep, displayLink.duration)
+    var frameDuration = animatedFrames[currentFrameIndex].duration
+
+    if timeSinceLastFrameChange >= frameDuration {
+      timeSinceLastFrameChange -= frameDuration
+      currentFrameIndex = ++currentFrameIndex % animatedFrames.count
+      delegate?.layer.setNeedsDisplay()
+    }
+  }
+
+  // MARK: - Animation
+  func pauseAnimation() {
+    displayLink.paused = true
+  }
+
+  func resumeAnimation() {
+    if isAnimated {
+      displayLink.paused = false
+    }
+  }
+
+  func isAnimating() -> Bool {
+    return !displayLink.paused
+  }
+}

Source/Functional.swift

@@ -0,0 +1,28 @@
+infix operator >>- { associativity left precedence 150 }
+infix operator <^> { associativity left precedence 150 }
+infix operator <*> { associativity left precedence 150 }
+
+func >>-<A, B>(a: A?, f: A -> B?) -> B? {
+  switch a {
+  case let .Some(x): return f(x)
+  case .None: return .None
+  }
+}
+
+func <^><A, B>(f: A -> B, a: A?) -> B? {
+  switch a {
+  case let .Some(x): return f(x)
+  case .None: return .None
+  }
+}
+
+func <*><A, B>(f: (A -> B)?, a: A?) -> B? {
+  switch f {
+  case let .Some(fx): return fx <^> a
+  case .None: return .None
+  }
+}
+
+func curry<A, B, C>(f: (A, B) -> C) -> A -> B -> C {
+  return { a in { b in f(a, b) } }
+}

Source/Gifu.swift

@@ -1,151 +0,0 @@
-import UIKit
-import ImageIO
-
-public class AnimatedImage: UIImage {
-  // MARK: - Constants
-  let framesToPreload = 10
-  let maxTimeStep = 1.0
-
-  // MARK: - Public Properties
-  var delegate: UIImageView?
-  var frameDurations = [NSTimeInterval]()
-  var frames = [UIImage?]()
-  var totalDuration: NSTimeInterval = 0.0
-
-  // MARK: - Private Properties
-  private lazy var displayLink: CADisplayLink = CADisplayLink(target: self, selector: "updateCurrentFrame")
-  private lazy var preloadFrameQueue = dispatch_queue_create("co.kaishin.GIFPreloadImages", DISPATCH_QUEUE_SERIAL)
-  private var currentFrameIndex = 0
-  private var imageSource: CGImageSource?
-  private var timeSinceLastFrameChange: NSTimeInterval = 0.0
-
-  // MARK: - Computed Properties
-  var currentFrame: UIImage? {
-    return frameAtIndex(currentFrameIndex)
-  }
-
-  private var isAnimated: Bool {
-    return imageSource != nil
-  }
-
-  // MARK: - Initializers
-  required public init(coder aDecoder: NSCoder) {
-    super.init(coder: aDecoder)
-  }
-
-  required public init(data: NSData, delegate: UIImageView?) {
-    let imageSource = CGImageSourceCreateWithData(data, nil)
-    self.delegate = delegate
-
-    if CGImageSourceContainsAnimatedGIF(imageSource) {
-      super.init()
-      attachDisplayLink()
-      prepareFrames(imageSource)
-      pauseAnimation()
-    } else {
-      super.init(data: data)
-    }
-  }
-
-  // MARK: - Factories
-  class func imageWithName(name: String, delegate: UIImageView?) -> Self? {
-    let path = NSBundle.mainBundle().bundlePath.stringByAppendingPathComponent(name)
-
-    if let data = NSData(contentsOfFile: path) {
-      return imageWithData(data, delegate: delegate)
-    }
-
-    return nil
-  }
-
-  class func imageWithData(data: NSData, delegate: UIImageView?) -> Self? {
-    return self(data: data, delegate: delegate)
-  }
-
-  // MARK: - Display Link Helpers
-  func attachDisplayLink() {
-    displayLink.addToRunLoop(NSRunLoop.mainRunLoop(), forMode: NSRunLoopCommonModes)
-  }
-
-  // MARK: - Frame Methods
-  private func prepareFrames(source: CGImageSource!) {
-    imageSource = source
-
-    let numberOfFrames = Int(CGImageSourceGetCount(self.imageSource))
-    frameDurations.reserveCapacity(numberOfFrames)
-    frames.reserveCapacity(numberOfFrames)
-
-    for index in 0..<numberOfFrames {
-      let frameDuration = CGImageSourceGIFFrameDuration(source, index)
-      frameDurations.append(frameDuration)
-      totalDuration += frameDuration
-
-      if index < framesToPreload {
-        let frameImageRef = CGImageSourceCreateImageAtIndex(self.imageSource, UInt(index), nil)
-        let frame = UIImage(CGImage: frameImageRef, scale: 0.0, orientation: UIImageOrientation.Up)
-        frames.append(frame)
-      } else {
-        frames.append(nil)
-      }
-    }
-  }
-
-  func frameAtIndex(index: Int) -> UIImage? {
-    if Int(index) >= self.frames.count { return nil }
-
-    var image: UIImage? = self.frames[Int(index)]
-    updatePreloadedFramesAtIndex(index)
-
-    return image
-  }
-
-  private func updatePreloadedFramesAtIndex(index: Int) {
-    if frames.count <= framesToPreload { return }
-
-    if index != 0 {
-      frames[index] = nil
-    }
-
-    for internalIndex in (index + 1)...(index + framesToPreload) {
-      let adjustedIndex = internalIndex % frames.count
-
-      if frames[adjustedIndex] == nil {
-        dispatch_async(preloadFrameQueue) {
-          let frameImageRef = CGImageSourceCreateImageAtIndex(self.imageSource, UInt(adjustedIndex), nil)
-          self.frames[adjustedIndex] = UIImage(CGImage: frameImageRef)
-        }
-      }
-    }
-  }
-
-  func updateCurrentFrame() {
-    if !isAnimated { return }
-
-    timeSinceLastFrameChange += min(maxTimeStep, displayLink.duration)
-    var frameDuration = frameDurations[currentFrameIndex]
-
-    while timeSinceLastFrameChange >= frameDuration {
-      timeSinceLastFrameChange -= frameDuration
-      currentFrameIndex++
-
-      if currentFrameIndex >= frames.count {
-        currentFrameIndex = 0
-      }
-
-      delegate?.layer.setNeedsDisplay()
-    }
-  }
-
-  // MARK: - Animation
-  func pauseAnimation() {
-    displayLink.paused = true
-  }
-
-  func resumeAnimation() {
-    displayLink.paused = false
-  }
-
-  func isAnimating() -> Bool {
-    return !displayLink.paused
-  }
-}

Source/ImageSourceHelpers.swift

@@ -2,7 +2,7 @@ import UIKit
 import ImageIO
 import MobileCoreServices
 
-func CGImageSourceContainsAnimatedGIF(imageSource: CGImageSource) -> Bool {
+private func CGImageSourceContainsAnimatedGIF(imageSource: CGImageSource) -> Bool {
   let isTypeGIF = UTTypeConformsTo(CGImageSourceGetType(imageSource), kUTTypeGIF)
   let imageCount = CGImageSourceGetCount(imageSource)
   return isTypeGIF != 0 && imageCount > 1

Source/UIImageExtension.swift

@@ -0,0 +1,16 @@
+extension UIImage {
+  func resize(size: CGSize) -> UIImage {
+    UIGraphicsBeginImageContext(size)
+    self.drawInRect(CGRectMake(0, 0, size.width, size.height))
+    let newImage = UIGraphicsGetImageFromCurrentImageContext()
+    UIGraphicsEndImageContext()
+    return newImage
+  }
+
+  class func imageWithData(data: NSData, size: CGSize) -> UIImage? {
+    return UIImage(data: data)?.resize(size)
+  }
+  class func sizeForImageData(data: NSData) -> CGSize? {
+    return UIImage(data: data)?.size
+  }
+}

Source/UIImageView+Gifu.swift

@@ -3,11 +3,7 @@ import UIKit
 public extension UIImageView {
   // MARK: - Computed Properties
   var animatableImage: AnimatedImage? {
-    if image is AnimatedImage {
+    return image as? AnimatedImage
-      return image as? AnimatedImage
-    } else {
-      return nil
-    }
   }
 
   var isAnimatingGIF: Bool {
@@ -15,43 +11,27 @@ public extension UIImageView {
   }
 
   var animatable: Bool {
-    return animatableImage != nil
+    return animatableImage != .None
   }
 
   // MARK: - Method Overrides
   override public func displayLayer(layer: CALayer!) {
-    if let image = animatableImage {
+    layer.contents = animatableImage?.currentFrame?.CGImage
-      if let frame = image.currentFrame {
-        layer.contents = frame.CGImage
-      }
-    }
   }
 
   // MARK: - Setter Methods
-  func setAnimatableImage(named name: String) {
+  public func setAnimatedImage(image: AnimatedImage) {
-    image = AnimatedImage.imageWithName(name, delegate: self)
+    image.delegate = self
-    layer.setNeedsDisplay()
+    self.image = image
-  }
-
-  func setAnimatableImage(#data: NSData) {
-    image = AnimatedImage.imageWithData(data, delegate: self)
     layer.setNeedsDisplay()
   }
 
   // MARK: - Animation
   func startAnimatingGIF() {
-    if animatable {
+    animatableImage?.resumeAnimation() ?? startAnimating()
-      animatableImage!.resumeAnimation()
-    } else {
-      startAnimating()
-    }
   }
 
   func stopAnimatingGIF() {
-    if animatable {
+    animatableImage?.pauseAnimation() ?? stopAnimating()
-      animatableImage!.pauseAnimation()
-    } else {
-      stopAnimating()
-    }
   }
 }