Swift: 如何删除用AVFoundation拍摄的照片中的EXIF数据？

Question

我正在尝试从使用 AVFoundation 拍摄的照片中删除 EXIF 数据，如何在 swift (2) preferred, Objective-C 也可以，我知道怎么把代码转成swift。

为什么？ 我做了我的研究，我看到很多著名的 Social Media（Reddit 源等）确实出于身份目的和其他目的删除了 EXIF 数据。

如果您认为这是重复的 post，请阅读我的问题并提供 link。谢谢。

Answer 1

我的回答很大程度上基于 this previous question。我修改了代码以在 Swift 2.0.

上工作

class ImageHelper {
  static func removeExifData(data: NSData) -> NSData? {
    guard let source = CGImageSourceCreateWithData(data, nil) else {
        return nil
    }
    guard let type = CGImageSourceGetType(source) else {
        return nil
    }
    let count = CGImageSourceGetCount(source)
    let mutableData = NSMutableData(data: data)
    guard let destination = CGImageDestinationCreateWithData(mutableData, type, count, nil) else {
        return nil
    }
    // Check the keys for what you need to remove
    // As per documentation, if you need a key removed, assign it kCFNull
    let removeExifProperties: CFDictionary = [String(kCGImagePropertyExifDictionary) : kCFNull, String(kCGImagePropertyOrientation): kCFNull]

    for i in 0..<count {
        CGImageDestinationAddImageFromSource(destination, source, i, removeExifProperties)
    }

    guard CGImageDestinationFinalize(destination) else {
        return nil
    }

    return mutableData;
  }
}

然后你可以简单地做这样的事情：

let imageData = ImageHelper.removeExifData(UIImagePNGRepresentation(image))

在我的示例中，我删除了旋转和 EXIF 数据。如果您需要删除任何其他内容，您可以轻松搜索密钥。只需对生成的数据进行额外检查，因为它是可选的。

Answer 2

你有 UIImage 吧？然后你可以将 UIImage 转换为数据并再次将其保存到图像新图像将没有任何 EXIF 数据

Swift 3

let imageData:Data = UIImagePNGRepresentation(image!)!



func saveToPhotoLibrary_iOS9(data:NSData, completionHandler: @escaping (PHAsset?)->()) {
    var assetIdentifier: String?
    PHPhotoLibrary.requestAuthorization { (status:PHAuthorizationStatus) in
        if(status == PHAuthorizationStatus.authorized){

            PHPhotoLibrary.shared().performChanges({
                let creationRequest = PHAssetCreationRequest.forAsset()
                let placeholder = creationRequest.placeholderForCreatedAsset

                creationRequest.addResource(with: PHAssetResourceType.photo, data: data as Data, options: nil)
                assetIdentifier = placeholder?.localIdentifier

            }, completionHandler: { (success, error) in
                if let error = error {
                    print("There was an error saving to the photo library: \(error)")
                }

                var asset: PHAsset? = nil
                if let assetIdentifier = assetIdentifier{
                    asset = PHAsset.fetchAssets(withLocalIdentifiers: [assetIdentifier], options: nil).firstObject//fetchAssetsWithLocalIdentifiers([assetIdentifier], options: nil).firstObject as? PHAsset
                }
                completionHandler(asset)
            })
        }else {
            print("Need authorisation to write to the photo library")
            completionHandler(nil)
        }
    }

}

Answer 3

Swift 5 个版本的接受答案：

extension Data {
    func byRemovingEXIF() -> Data? {
        guard let source = CGImageSourceCreateWithData(self as NSData, nil),
              let type = CGImageSourceGetType(source) else
        {
            return nil
        }

        let count = CGImageSourceGetCount(source)
        let mutableData = NSMutableData()
        guard let destination = CGImageDestinationCreateWithData(mutableData, type, count, nil) else {
            return nil
        }

        let exifToRemove: CFDictionary = [
            kCGImagePropertyExifDictionary: kCFNull,
            kCGImagePropertyGPSDictionary: kCFNull,
        ] as CFDictionary

        for index in 0 ..< count {
            CGImageDestinationAddImageFromSource(destination, source, index, exifToRemove)
            if !CGImageDestinationFinalize(destination) {
                print("Failed to finalize")
            }
        }

        return mutableData as Data
    }
}

Answer 4

这是一个从原始数据中删除 exif 的解决方案。 jpeg 中的 Exif 在 APP1 框架内。帧开始用 FF_E1 表示。帧结束于下一个不跟在 00 值之后的 FF 字节。

var data: Data = ... // read jpeg one way or another 
var app1_start = 0
var app1_end = Int.max
for i in 0 ..< data.count {
    if data[i] == 0xFF {
        if data[i + 1] == 0xE1 {
            print("found start \(i)")
            app1_start = i
        } else if app1_start > 0, data [i] != 0x00 {
            app1_end = i - 1
            print("found end \(i-1)")
            break
        }
    }
}
data.removeSubrange(Range(app1_start...app1_end))

假设此示例中的数据为 jpeg。代码循环遍历字节数组并存储 APP1 的开始和结束。然后从原始可变数据中删除数据。更多关于 jpeg 结构的信息 https://en.wikipedia.org/wiki/JPEG

Swift: 如何删除用AVFoundation拍摄的照片中的EXIF数据？

Swift: How to Delete EXIF data from picture taken with AVFoundation?

exif

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