在swift 3.0中將圖像轉換爲逐行JPEG

Question

我需要使用swift 3.0將我的UIImage轉換爲漸進式jpeg。 我發現在迅速2.2以下代碼：

let sourceImage = UIImage(named: "example.jpg") 
let path = (NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSString).stringByAppendingPathComponent("progressive.jpg") 
let fileUrl = NSURL(fileURLWithPath: path as String, isDirectory: true) 
let url = CFURLCreateWithString(kCFAllocatorDefault,fileUrl.absoluteString as CFString , nil) 
let destinationRef = CGImageDestinationCreateWithURL(url, kUTTypeJPEG, 1, nil) 
let jfifProperties = NSDictionary(dictionary: [kCGImagePropertyJFIFIsProgressive:kCFBooleanTrue]) 
let properties = NSDictionary(dictionary: [kCGImageDestinationLossyCompressionQuality:0.6,kCGImagePropertyJFIFDictionary:jfifProperties]) 
CGImageDestinationAddImage(destinationRef!, (sourceImage?.CGImage)!, properties) 
CGImageDestinationFinalize(destinationRef!) 

不過，這並不在SWIFT 3.0。 CGImageDestinationCreateWithURL給出錯誤（所有的CGImage類...）有什麼幫助？謝謝！

Answer 1

阿譯斯威夫特3將與此類似：

guard let sourceImage = UIImage(named: "example.jpg") else { 
    fatalError("Image could not be loaded") 
} 

let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] 
let targetUrl = documentsUrl.appendingPathComponent("progressive.jpg") as CFURL 

let destination = CGImageDestinationCreateWithURL(targetUrl, kUTTypeJPEG, 1, nil)! 
let jfifProperties = [kCGImagePropertyJFIFIsProgressive: kCFBooleanTrue] as NSDictionary 
let properties = [ 
    kCGImageDestinationLossyCompressionQuality: 0.6, 
    kCGImagePropertyJFIFDictionary: jfifProperties 
] as NSDictionary 

CGImageDestinationAddImage(destination, sourceImage.cgImage!, properties) 
CGImageDestinationFinalize(destination) 

不要忘了必要的模塊導入：

import UIKit 
import ImageIO 
import MobileCoreServices