如何将PHLivePhoto转换为UIImage？

Question

在我的应用程序中，我有一段代码，其中需要说明PHLivePhoto类型的对象，并将其转换为UIImage。我认为这与PHAsset、PHAssetResource或PHImageManager有关，但不清楚如何执行转换。如何从PHLivePhoto -> UIImage转换的好方法是什么？谢谢你的帮助！

if let livePhoto = object as? PHLivePhoto {
    let livePhotoResources = PHAssetResource.assetResources(for: livePhoto)
    print("\(livePhotoResources)")
    
    // imageBucket is of type UIImage[]
    // livePhoto is of type PHLivePhoto but I don't know how to convert this to type PHAsset
    viewModel.imageBucket.append(convertImageAsset(asset: **WHAT_DO_I_INSERT_HERE**))
}

..。

func convertImageAsset(asset: PHAsset) -> UIImage {
            let manager = PHImageManager.default()
            let option = PHImageRequestOptions()
            var tmpImage = UIImage()
            option.isSynchronous = true
            manager.requestImage(
                for: asset,
                   targetSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight),
                   contentMode: .aspectFit,
                   options: option,
                   resultHandler: {(result, info)->Void in
                       tmpImage = result!
                   })
            return tmpImage
        }

在以下方面的成果：

[<PHAssetResource: 0x28225cdc0> {
    type: photo
    uti: public.heic
    filename: IMG_5442.heic
    asset: (null)
    locallyAvailable: YES
    fileURL: file:///private/var/mobile/Containers/Data/Application/2FB56305-7600-4A8E-9C67-A71B4A4A9607/tmp/live-photo-bundle/75FD3D97-F13E-4F79-A6E9-F0743D443FDD.pvt/IMG_5442.HEIC
    width: 0
    height: 0
    fileSize: 0
    analysisType: unavailable
    cplResourceType: Unknown
    isCurrent: NO
    isInCloud: NO
}, <PHAssetResource: 0x28226bc00> {
    type: video_cmpl
    uti: com.apple.quicktime-movie
    filename: IMG_5442.mov
    asset: (null)
    locallyAvailable: YES
    fileURL: file:///private/var/mobile/Containers/Data/Application/2FB56305-7600-4A8E-9C67-A71B4A4A9607/tmp/live-photo-bundle/75FD3D97-F13E-4F79-A6E9-F0743D443FDD.pvt/IMG_5442.MOV
    width: 0
    height: 0
    fileSize: 0
    analysisType: unavailable
    cplResourceType: Unknown
    isCurrent: NO
    isInCloud: NO
}]

Answer 1

您需要使用PHAsset来获取资产，然后从PHImageManager.default()请求图像数据。

func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    dismiss(animated: true)
    
    guard let assetIdentifier = results.first?.assetIdentifier  else {
        return
    }
    
    if let phAsset = PHAsset.fetchAssets(withLocalIdentifiers: [assetIdentifier], options: nil).firstObject {
        PHImageManager.default().requestImageDataAndOrientation(for: phAsset, options: nil) { [weak self] data, _, _, _ in
            if let data = data, let image = UIImage(data: data) {
                self?.viewModel.imageBucket.append(image)
            }
        }
    }
}

要获得assetIdentifier，需要使用共享照片库创建PHPickerConfiguration对象。创建没有照片库的配置只提供资产数据，而不包括资产标识符。

var configuration = PHPickerConfiguration(photoLibrary: .shared())
// Set the filter type according to the user’s selection. .images is a filter to display images, including Live Photos.
configuration.filter = .images
// Set the mode to avoid transcoding, if possible, if your app supports arbitrary image/video encodings.
configuration.preferredAssetRepresentationMode = .current
// Set the selection limit.
configuration.selectionLimit = 1
    
let picker = PHPickerViewController(configuration: configuration)
picker.delegate = self
present(picker, animated: true)

Answer 2

接受的答案的问题是，获取PHAsset将需要访问照片库，而PHPickerViewController的主要优点之一是能够在不请求权限的情况下获取照片，并且完全避免了所有相关的边缘情况。

因此，另一种获取实时照片的方法是：

func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    for result in results {
        // Live photos
        if result.itemProvider.canLoadObject(ofClass: PHLivePhoto.self) {
            result.itemProvider.loadObject(ofClass: PHLivePhoto.self, completionHandler: { livePhoto, error in
                let resources = PHAssetResource.assetResources(for: livePhoto as! PHLivePhoto)
                let photo = resources.first(where: { $0.type == .photo })!
                let imageData = NSMutableData()
                
                PHAssetResourceManager.default().requestData(for: photo, options: nil, dataReceivedHandler: { data in
                    imageData.append(data)
                }, completionHandler: { error in
                    _ = UIImage(data: imageData as Data)!
                })
            })
        }
    }
}