Generating a GIF from UIImages (Swift 3)

generateGif.swift

func generateGif(photos: [UIImage], filename: String) -> Bool {
  if let docsDirectory = getDocumentsDirectory() {
    let url = docsDirectory.appendingPathComponent(filename)
    let fileProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFLoopCount as String: 0]]
    let gifProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFDelayTime as String: 0.125]]
    if let destination = CGImageDestinationCreateWithURL(url as CFURL, kUTTypeGIF, photos.count, nil) {
      CGImageDestinationSetProperties(destination, fileProperties as CFDictionary?)
      for photo in photos {
        CGImageDestinationAddImage(destination, photo.cgImage!, gifProperties as CFDictionary?)
      }
      return CGImageDestinationFinalize(destination)
    }
  }
  return false
}

func getDocumentsDirectory() -> URL?  {
  return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
}