Swift:自定义相机使用图像保存已修改的元数据 [英] Swift: Custom camera save modified metadata with image
问题描述
我试图将图像样本缓冲区中的一些元数据与图像一起保存。
I am trying to save SOME of the metadata from an image sample buffer along with the image.
我需要:
- 将图像旋转到元数据的方向
- 从元数据中删除方向
- 保存采用元数据的日期
- 使用以下方法保存该图像元数据到文档目录
- Rotate the image to the orientation from the metadata
- Remove orientation from the metadata
- Save the date taken to the metadata
- Save that image with the metadata to the documents directory
我尝试从数据创建UIImage,但是删除了元数据。我已经尝试使用数据中的CIImage来保存元数据,但是我无法将其旋转然后将其保存到文件中。
I have tried creating a UIImage from the data, but that strips out the metadata. I have tried using a CIImage from the data, which keeps the metadata, but I can't rotate it then save it to a file.
private func snapPhoto(success: (UIImage, CFMutableDictionary) -> Void, errorMessage: String -> Void) {
guard !self.stillImageOutput.capturingStillImage,
let videoConnection = stillImageOutput.connectionWithMediaType(AVMediaTypeVideo) else { return }
videoConnection.fixVideoOrientation()
stillImageOutput.captureStillImageAsynchronouslyFromConnection(videoConnection) {
(imageDataSampleBuffer, error) -> Void in
guard imageDataSampleBuffer != nil && error == nil else {
errorMessage("Couldn't snap photo")
return
}
let data = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer)
let metadata = CMCopyDictionaryOfAttachments(nil, imageDataSampleBuffer, CMAttachmentMode(kCMAttachmentMode_ShouldPropagate))
let metadataMutable = CFDictionaryCreateMutableCopy(nil, 0, metadata)
let utcDate = "\(NSDate())"
let cfUTCDate = CFStringCreateCopy(nil, utcDate)
CFDictionarySetValue(metadataMutable!, unsafeAddressOf(kCGImagePropertyGPSDateStamp), unsafeAddressOf(cfUTCDate))
guard let image = UIImage(data: data)?.fixOrientation() else { return }
CFDictionarySetValue(metadataMutable, unsafeAddressOf(kCGImagePropertyOrientation), unsafeAddressOf(1))
success(image, metadataMutable)
}
}
这是我保存图片的代码。
Here is my code for saving the image.
func saveImageAsJpg(image: UIImage, metadata: CFMutableDictionary) {
// Add metadata to image
guard let jpgData = UIImageJPEGRepresentation(image, 1) else { return }
jpgData.writeToFile("\(self.documentsDirectory)/image1.jpg", atomically: true)
}
推荐答案
我最终弄清楚如何让一切按照我需要的方式工作。对我帮助最大的事情是发现CFDictionary可以作为NSMutableDictionary投射。
I ended up figuring out how to get everything to work the way I needed it to. The thing that helped me the most was finding out that a CFDictionary can be cast as a NSMutableDictionary.
这是我的最终代码:
如你所见,我在EXIF词典中添加了一个属性日期数字化,并更改了方向值。
As you can see I add a property to the EXIF dictionary for the date digitized, and changed the orientation value.
private func snapPhoto(success: (UIImage, NSMutableDictionary) -> Void, errorMessage: String -> Void) {
guard !self.stillImageOutput.capturingStillImage,
let videoConnection = stillImageOutput.connectionWithMediaType(AVMediaTypeVideo) else { return }
videoConnection.fixVideoOrientation()
stillImageOutput.captureStillImageAsynchronouslyFromConnection(videoConnection) {
(imageDataSampleBuffer, error) -> Void in
guard imageDataSampleBuffer != nil && error == nil else {
errorMessage("Couldn't snap photo")
return
}
let data = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer)
let rawMetadata = CMCopyDictionaryOfAttachments(nil, imageDataSampleBuffer, CMAttachmentMode(kCMAttachmentMode_ShouldPropagate))
let metadata = CFDictionaryCreateMutableCopy(nil, 0, rawMetadata) as NSMutableDictionary
let exifData = metadata.valueForKey(kCGImagePropertyExifDictionary as String) as? NSMutableDictionary
exifData?.setValue(NSDate().toString("yyyy:MM:dd HH:mm:ss"), forKey: kCGImagePropertyExifDateTimeDigitized as String)
metadata.setValue(exifData, forKey: kCGImagePropertyExifDictionary as String)
metadata.setValue(1, forKey: kCGImagePropertyOrientation as String)
guard let image = UIImage(data: data)?.fixOrientation() else {
errorMessage("Couldn't create image")
return
}
success(image, metadata)
}
}
以及使用元数据保存图像的最终代码:
And my final code for saving the image with the metadata:
我讨厌的很多防守声明,但它比强制解包更好。
Lots of guard statements, which I hate, but it is better than force unwrapping.
func saveImage(withMetadata image: UIImage, metadata: NSMutableDictionary) {
let filePath = "\(self.documentsPath)/image1.jpg"
guard let jpgData = UIImageJPEGRepresentation(image, 1) else { return }
// Add metadata to jpgData
guard let source = CGImageSourceCreateWithData(jpgData, nil),
let uniformTypeIdentifier = CGImageSourceGetType(source) else { return }
let finalData = NSMutableData(data: jpgData)
guard let destination = CGImageDestinationCreateWithData(finalData, uniformTypeIdentifier, 1, nil) else { return }
CGImageDestinationAddImageFromSource(destination, source, 0, metadata)
guard CGImageDestinationFinalize(destination) else { return }
// Save image that now has metadata
self.fileService.save(filePath, data: finalData)
}
这是我更新的保存
方法(不完全相同)当我写这个问题时我正在使用,因为我已经更新到Swift 2.3,但概念是相同的):
Here is my updated save
method (Not the exact same that I was using when I wrote this question, since I have updated to Swift 2.3, but the concept is the same):
public func save(fileAt path: NSURL, with data: NSData) throws -> Bool {
guard let pathString = path.absoluteString else { return false }
let directory = (pathString as NSString).stringByDeletingLastPathComponent
if !self.fileManager.fileExistsAtPath(directory) {
try self.makeDirectory(at: NSURL(string: directory)!)
}
if self.fileManager.fileExistsAtPath(pathString) {
try self.delete(fileAt: path)
}
return self.fileManager.createFileAtPath(pathString, contents: data, attributes: [NSFileProtectionKey: NSFileProtectionComplete])
}
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