iOS Swift. How to get a GPS metadata from just a UIImage (NSURL)?

问题:

Have a reference to an image only having its NSURL. How to get a GPS metadata from it? Of course, I can load a UIImage from NSURL, but then what?

Majority of answers I've found here is regarding UIImagePicker, and using ALAssets then, but I have no such option.

回答1:

Answering my own question. The memory-effective and fast way to get a GPS metadata is

let options = [kCGImageSourceShouldCache as String: kCFBooleanFalse] if let data = NSData(contentsOfURL: url), imgSrc = CGImageSourceCreateWithData(data, options) {     let metadata = CGImageSourceCopyPropertiesAtIndex(imgSrc, 0, options) as Dictionary     let gpsData = metadata[kCGImagePropertyGPSDictionary] as? [String : AnyObject] }

The second option is

if let img = CIImage(contentsOfURL: url), metadata = img.properties(),  gpsData = metadata[kCGImagePropertyGPSDictionary] as? [String : AnyObject] { … }

it looks nicer in Swift but uses more memory (tested via Profiler).

回答2:

Updated version for Swift 3:

let options = [kCGImageSourceShouldCache as String: kCFBooleanFalse] if let data = NSData(contentsOfURL: url), let imgSrc = CGImageSourceCreateWithData(data, options as CFDictionary) {     let metadata = CGImageSourceCopyPropertiesAtIndex(imgSrc, 0, options as CFDictionary) as? [String : AnyObject]     if let gpsData = metadata?[kCGImagePropertyGPSDictionary as String] {         //do interesting stuff here     } }

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