iOS Swift。如何从UIImage（NSURL）获取GPS元数据？ [英] iOS Swift. How to get a GPS metadata from just a UIImage (NSURL)?

问题描述

引用仅具有NSURL的图像。
如何从中获取GPS元数据？
当然，我可以从NSURL加载UIImage，但接下来是什么？

我在这里找到的大部分答案都是关于UIImagePicker，然后使用ALAssets ，但我没有这样的选择。 解决方案

回答我自己的问题。获取GPS元数据的内存有效和快速的方式是

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

第二个选项是

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

它在Swift中看起来更好，但使用更多内存（通过Profiler ）。

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.

解决方案

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).

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