Merge pull request onevcat#861 from mliberatore/fix-loop-counting

Fixes Gif Loop Counting and Frame Skipping
CoericK · Feb 14, 2018 · 0616898 · 0616898
2 parents 43ec2d2 + 5c42022
commit 0616898
Showing 1 changed file with 13 additions and 9 deletions.
diff --git a/Sources/AnimatedImageView.swift b/Sources/AnimatedImageView.swift
@@ -305,6 +305,7 @@ class Animator {
     fileprivate let maxTimeStep: TimeInterval = 1.0
     fileprivate var frameCount = 0
     fileprivate var currentFrameIndex = 0
+    fileprivate var currentFrameIndexInBuffer = 0
     fileprivate var currentPreloadIndex = 0
     fileprivate var timeSinceLastFrameChange: TimeInterval = 0.0
     fileprivate var needsPrescaling = true
@@ -315,7 +316,7 @@ class Animator {
     private var loopCount = 0
 
     var currentFrame: UIImage? {
-        return frame(at: currentFrameIndex)
+        return frame(at: currentFrameIndexInBuffer)
     }
 
     var isReachMaxRepeatCount: Bool {
@@ -380,7 +381,7 @@ class Animator {
         let frameToProcess = min(frameCount, maxFrameCount)
         animatedFrames.reserveCapacity(frameToProcess)
         animatedFrames = (0..<frameToProcess).reduce([]) { $0 + pure(prepareFrame(at: $1))}
-        currentPreloadIndex = (frameToProcess + 1) % frameCount
+        currentPreloadIndex = (frameToProcess + 1) % frameCount - 1
     }
 
     private func prepareFrame(at index: Int) -> AnimatedFrame {
@@ -426,21 +427,24 @@ class Animator {
      */
     func updateCurrentFrame(duration: CFTimeInterval) -> Bool {
         timeSinceLastFrameChange += min(maxTimeStep, duration)
-        guard let frameDuration = animatedFrames[safe: currentFrameIndex]?.duration, frameDuration <= timeSinceLastFrameChange else {
+        guard let frameDuration = animatedFrames[safe: currentFrameIndexInBuffer]?.duration, frameDuration <= timeSinceLastFrameChange else {
             return false
         }
 
         timeSinceLastFrameChange -= frameDuration
 
-        let lastFrameIndex = currentFrameIndex
-        currentFrameIndex += 1
-        currentFrameIndex = currentFrameIndex % animatedFrames.count
-
+        let lastFrameIndex = currentFrameIndexInBuffer
+        currentFrameIndexInBuffer += 1
+        currentFrameIndexInBuffer = currentFrameIndexInBuffer % animatedFrames.count
+        
         if animatedFrames.count < frameCount {
             preloadFrameAsynchronously(at: lastFrameIndex)
         }
-
-        if currentFrameIndex == 0 {
+
+        currentFrameIndex += 1
+
+        if currentFrameIndex == frameCount {
+            currentFrameIndex = 0
             currentRepeatCount += 1
 
             delegate?.animator(self, didPlayAnimationLoops: currentRepeatCount)