Create GIF from UIImages in Swift

createGIF

import CoreGraphics
import ImageIO
import MobileCoreServices

func createGIF(with images: [UIImage], loopCount: Int = 0, frameDelay: Double, callback: (dataURL: NSURL?, error: NSError?) -> ()) {
    let fileProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFLoopCount as String: loopCount]]
    let frameProperties = [kCGImagePropertyGIFDictionary as String: [kCGImagePropertyGIFDelayTime as String: frameDelay]]

    let documentsDirectory = NSTemporaryDirectory()
    let url = NSURL(fileURLWithPath: documentsDirectory).URLByAppendingPathComponent("animated.gif")

    let destination = CGImageDestinationCreateWithURL(url, kUTTypeGIF, Int(images.count), nil)
    CGImageDestinationSetProperties(destination!, fileProperties)

    for i in 0..<images.count {
        CGImageDestinationAddImage(destination!, images[i].CGImage!, frameProperties)
    }

    if CGImageDestinationFinalize(destination!) {
        callback(dataURL: url, error: nil)
    } else {
        callback(dataURL: nil, error: NSError(domain: "createGIF", code: 0, userInfo: nil))
    }
}