Photos.png
介绍
苹果的PhotoKit,是提供给开发者的对本地相册库的和iCloud 相册的资源进行操作的API,所有资源以PHAsset的形式来提供给PhotoKit使用,同时本地的图片库和iCloud图片的变动通知,会发送给PhotoKit;同时,PhotoKit也可以通过 变更请求 (编辑请求,改变请求,删除请求...)来对资源进行变更.
资源的操作
PHPhotoLibrary.shared().register(self); // viewDidLoad 执行
PHPhotoLibrary.shared().unregisterChangeObserver(self);//deinit 方法中执行
extension MasterViewController: PHPhotoLibraryChangeObserver {//资源变动后的通知
/// - Tag: RespondToChanges
func photoLibraryDidChange(_ changeInstance: PHChange) {
// Change notifications may originate from a background queue.
// Re-dispatch to the main queue before acting on the change,
// so you can update the UI.
DispatchQueue.main.sync {
}
}
}
资源的查找
排序和筛选条件我们可以根据 PHFetchOptions里面的 predicate 和 sortDescriptors 属性来设置, 里面也包含支持 predicate 和 sort 的 keys, 可以参考 NSPredicate 和 NSSortDescriptor 来了解更多筛选和排序条件的设置.
PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .albumRegular, options: nil)//智能相册
PHCollectionList.fetchTopLevelUserCollections(with: nil)//用户相册
PHAsset.fetchAssets(with: phtotfectchOptions)//图片资源
资源的变更请求
//Asynchronously runs a block that requests changes to be performed in the photo library. 异步请求
func performChanges(_:completionHandler:)
//Synchronously runs a block that requests changes to be performed in the photo library. 同步请求
func performChangesAndWait(_ changeBlock: @escaping () -> Void) throws
Album的操作(增加,修改,删除)
//增加相册
func addAlbum() {
PHPhotoLibrary.shared().performChanges({
let assetCollectionRequest = PHCollectionListChangeRequest.creationRequestForCollectionList(withTitle: "title");
self.identifier = assetCollectionRequest.placeholderForCreatedCollectionList.localIdentifier;
}) { (ret, error) in
if ret {
if let id = self.identifier {
let collections = PHCollectionList.fetchCollectionLists(withLocalIdentifiers: [id], options: nil)
print("\(collections)");
}
}
}
}
//删除相册
func deleteAlbum() {
let fecthOptions = PHFetchOptions();
let predicate = NSPredicate.init(format: "localizedTitle == 'title'");
fecthOptions.predicate = predicate;
let titleList = PHCollectionList.fetchCollectionLists(with: .folder, subtype: .regularFolder, options: fecthOptions);
PHPhotoLibrary.shared().performChanges({
PHCollectionListChangeRequest.deleteCollectionLists(titleList);
}) { (ret, error) in
if ret {
print("删除成功");
}
}
}
//修改相册
func modifyAlbum() {
let fecthOptions = PHFetchOptions();
let predicate = NSPredicate.init(format: "localizedTitle == 'title'");
fecthOptions.predicate = predicate;
let titleList = PHCollectionList.fetchCollectionLists(with: .folder, subtype: .regularFolder, options: fecthOptions);
PHPhotoLibrary.shared().performChanges({
if let collection = titleList.firstObject {
let modifyRequest = PHCollectionListChangeRequest(for: collection);
modifyRequest?.title = "modify album";
}
}) { (ret, error) in
if ret {
print("修改成功");
}
}
}
Asset的操作
//增加
func creationRequestForAsset(from image: UIImage) -> Self
func creationRequestForAssetFromImage(atFileURL fileURL: URL) -> Self?
func creationRequestForAssetFromVideo(atFileURL fileURL: URL) -> Self?
//删除
func deleteAssets(_ assets: NSFastEnumeration)
//修改
func requestContentEditingInput(with options: PHContentEditingInputRequestOptions?, completionHandler: @escaping (PHContentEditingInput?, [AnyHashable : Any]) -> Void) -> PHContentEditingInputRequestID
func cancelContentEditingInputRequest(_ requestID: PHContentEditingInputRequestID)
// MARK: UI Actions
/// - Tag: EditAlert
@IBAction func editAsset(_ sender: UIBarButtonItem) {
// Use a UIAlertController to display editing options to the user.
let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
#if os(iOS)
alertController.modalPresentationStyle = .popover
if let popoverController = alertController.popoverPresentationController {
popoverController.barButtonItem = sender
popoverController.permittedArrowDirections = .up
}
#endif
// Add a Cancel action to dismiss the alert without doing anything.
alertController.addAction(UIAlertAction(title: NSLocalizedString("Cancel", comment: ""),
style: .cancel, handler: nil))
// Allow editing only if the PHAsset supports edit operations.
if asset.canPerform(.content) {
// Add actions for some canned filters.
alertController.addAction(UIAlertAction(title: NSLocalizedString("Sepia Tone", comment: ""),
style: .default, handler: getFilter("CISepiaTone")))
alertController.addAction(UIAlertAction(title: NSLocalizedString("Chrome", comment: ""),
style: .default, handler: getFilter("CIPhotoEffectChrome")))
// Add actions to revert any edits that have been made to the PHAsset.
alertController.addAction(UIAlertAction(title: NSLocalizedString("Revert", comment: ""),
style: .default, handler: revertAsset))
}
// Present the UIAlertController.
present(alertController, animated: true)
}
#if os(tvOS)
@IBAction func playLivePhoto(_ sender: Any) {
livePhotoView.startPlayback(with: .full)
}
#endif
/// - Tag: PlayVideo
@IBAction func play(_ sender: AnyObject) {
if playerLayer != nil {
// The app already created an AVPlayerLayer, so tell it to play.
playerLayer.player!.play()
} else {
let options = PHVideoRequestOptions()
options.isNetworkAccessAllowed = true
options.deliveryMode = .automatic
options.progressHandler = { progress, _, _, _ in
// The handler may originate on a background queue, so
// re-dispatch to the main queue for UI work.
DispatchQueue.main.sync {
self.progressView.progress = Float(progress)
}
}
// Request an AVPlayerItem for the displayed PHAsset.
// Then configure a layer for playing it.
PHImageManager.default().requestPlayerItem(forVideo: asset, options: options, resultHandler: { playerItem, info in
DispatchQueue.main.sync {
guard self.playerLayer == nil else { return }
// Create an AVPlayer and AVPlayerLayer with the AVPlayerItem.
let player = AVPlayer(playerItem: playerItem)
let playerLayer = AVPlayerLayer(player: player)
// Configure the AVPlayerLayer and add it to the view.
playerLayer.videoGravity = AVLayerVideoGravity.resizeAspect
playerLayer.frame = self.view.layer.bounds
self.view.layer.addSublayer(playerLayer)
player.play()
// Cache the player layer by reference, so you can remove it later.
self.playerLayer = playerLayer
}
})
}
}
/// - Tag: RemoveAsset
@IBAction func removeAsset(_ sender: AnyObject) {
let completion = { (success: Bool, error: Error?) -> Void in
if success {
PHPhotoLibrary.shared().unregisterChangeObserver(self)
DispatchQueue.main.sync {
_ = self.navigationController!.popViewController(animated: true)
}
} else {
print("Can't remove the asset: \(String(describing: error))")
}
}
if assetCollection != nil {
// Remove the asset from the selected album.
PHPhotoLibrary.shared().performChanges({
let request = PHAssetCollectionChangeRequest(for: self.assetCollection)!
request.removeAssets([self.asset] as NSArray)
}, completionHandler: completion)
} else {
// Delete the asset from the photo library.
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.deleteAssets([self.asset] as NSArray)
}, completionHandler: completion)
}
}
/// - Tag: MarkFavorite
@IBAction func toggleFavorite(_ sender: UIBarButtonItem) {
PHPhotoLibrary.shared().performChanges({
let request = PHAssetChangeRequest(for: self.asset)
request.isFavorite = !self.asset.isFavorite
}, completionHandler: { success, error in
if success {
DispatchQueue.main.sync {
sender.title = self.asset.isFavorite ? "♥︎" : "♡"
}
} else {
print("Can't mark the asset as a Favorite: \(String(describing: error))")
}
})
}
// MARK: Image display
var targetSize: CGSize {
let scale = UIScreen.main.scale
return CGSize(width: imageView.bounds.width * scale, height: imageView.bounds.height * scale)
}
func updateImage() {
if asset.mediaSubtypes.contains(.photoLive) {
updateLivePhoto()
} else {
updateStaticImage()
}
}
func updateLivePhoto() {
// Prepare the options to pass when fetching the live photo.
let options = PHLivePhotoRequestOptions()
options.deliveryMode = .highQualityFormat
options.isNetworkAccessAllowed = true
options.progressHandler = { progress, _, _, _ in
// The handler may originate on a background queue, so
// re-dispatch to the main queue for UI work.
DispatchQueue.main.sync {
self.progressView.progress = Float(progress)
}
}
// Request the live photo for the asset from the default PHImageManager.
PHImageManager.default().requestLivePhoto(for: asset, targetSize: targetSize, contentMode: .aspectFit, options: options,
resultHandler: { livePhoto, info in
// PhotoKit finishes the request, so hide the progress view.
self.progressView.isHidden = true
// Show the Live Photo view.
guard let livePhoto = livePhoto else { return }
// Show the Live Photo.
self.imageView.isHidden = true
self.livePhotoView.isHidden = false
self.livePhotoView.livePhoto = livePhoto
if !self.isPlayingHint {
// Play back a short section of the Live Photo, similar to the Photos share sheet.
self.isPlayingHint = true
self.livePhotoView.startPlayback(with: .hint)
}
})
}
func updateStaticImage() {
// Prepare the options to pass when fetching the (photo, or video preview) image.
let options = PHImageRequestOptions()
options.deliveryMode = .highQualityFormat
options.isNetworkAccessAllowed = true
options.progressHandler = { progress, _, _, _ in
// The handler may originate on a background queue, so
// re-dispatch to the main queue for UI work.
DispatchQueue.main.sync {
self.progressView.progress = Float(progress)
}
}
PHImageManager.default().requestImage(for: asset, targetSize: targetSize, contentMode: .aspectFit, options: options,
resultHandler: { image, _ in
// PhotoKit finished the request, so hide the progress view.
self.progressView.isHidden = true
// If the request succeeded, show the image view.
guard let image = image else { return }
// Show the image.
self.livePhotoView.isHidden = true
self.imageView.isHidden = false
self.imageView.image = image
})
}
// MARK: Asset editing
func revertAsset(sender: UIAlertAction) {
PHPhotoLibrary.shared().performChanges({
let request = PHAssetChangeRequest(for: self.asset)
request.revertAssetContentToOriginal()
}, completionHandler: { success, error in
if !success { print("Can't revert the asset: \(String(describing: error))") }
})
}
// Returns a filter-applier function for the named filter.
// Use the function as a handler for a UIAlertAction object.
/// - Tag: ApplyFilter
func getFilter(_ filterName: String) -> (UIAlertAction) -> Void {
func applyFilter(_: UIAlertAction) {
// Set up a handler to handle prior edits.
let options = PHContentEditingInputRequestOptions()
options.canHandleAdjustmentData = {
$0.formatIdentifier == self.formatIdentifier && $0.formatVersion == self.formatVersion
}
// Prepare for editing.
asset.requestContentEditingInput(with: options, completionHandler: { input, info in
guard let input = input
else { fatalError("Can't get the content-editing input: \(info)") }
// This handler executes on the main thread; dispatch to a background queue for processing.
DispatchQueue.global(qos: .userInitiated).async {
// Create adjustment data describing the edit.
let adjustmentData = PHAdjustmentData(formatIdentifier: self.formatIdentifier,
formatVersion: self.formatVersion,
data: filterName.data(using: .utf8)!)
// Create content editing output, write the adjustment data.
let output = PHContentEditingOutput(contentEditingInput: input)
output.adjustmentData = adjustmentData
// Select a filtering function for the asset's media type.
let applyFunc: (String, PHContentEditingInput, PHContentEditingOutput, @escaping () -> Void) -> Void
if self.asset.mediaSubtypes.contains(.photoLive) {
applyFunc = self.applyLivePhotoFilter
} else if self.asset.mediaType == .image {
applyFunc = self.applyPhotoFilter
} else {
applyFunc = self.applyVideoFilter
}
// Apply the filter.
applyFunc(filterName, input, output, {
// When the app finishes rendering the filtered result, commit the edit to the photo library.
PHPhotoLibrary.shared().performChanges({
let request = PHAssetChangeRequest(for: self.asset)
request.contentEditingOutput = output
}, completionHandler: { success, error in
if !success { print("Can't edit the asset: \(String(describing: error))") }
})
})
}
})
}
return applyFilter
}
func applyPhotoFilter(_ filterName: String, input: PHContentEditingInput, output: PHContentEditingOutput, completion: () -> Void) {
// Load the full-size image.
guard let inputImage = CIImage(contentsOf: input.fullSizeImageURL!)
else { fatalError("Can't load the input image to edit.") }
// Apply the filter.
let outputImage = inputImage
.oriented(forExifOrientation: input.fullSizeImageOrientation)
.applyingFilter(filterName, parameters: [:])
// Write the edited image as a JPEG.
do {
try self.ciContext.writeJPEGRepresentation(of: outputImage,
to: output.renderedContentURL, colorSpace: inputImage.colorSpace!, options: [:])
} catch let error {
fatalError("Can't apply the filter to the image: \(error).")
}
completion()
}
func applyLivePhotoFilter(_ filterName: String, input: PHContentEditingInput, output: PHContentEditingOutput, completion: @escaping () -> Void) {
// This app filters assets only for output. In an app that previews
// filters while editing, create a livePhotoContext early and reuse it
// to render both for previewing and for final output.
guard let livePhotoContext = PHLivePhotoEditingContext(livePhotoEditingInput: input)
else { fatalError("Can't fetch the Live Photo to edit.") }
livePhotoContext.frameProcessor = { frame, _ in
return frame.image.applyingFilter(filterName, parameters: [:])
}
livePhotoContext.saveLivePhoto(to: output) { success, error in
if success {
completion()
} else {
print("Can't output the Live Photo.")
}
}
}
func applyVideoFilter(_ filterName: String, input: PHContentEditingInput, output: PHContentEditingOutput, completion: @escaping () -> Void) {
// Load the AVAsset to process from input.
guard let avAsset = input.audiovisualAsset
else { fatalError("Can't fetch the AVAsset to edit.") }
// Set up a video composition to apply the filter.
let composition = AVVideoComposition(
asset: avAsset,
applyingCIFiltersWithHandler: { request in
let filtered = request.sourceImage.applyingFilter(filterName, parameters: [:])
request.finish(with: filtered, context: nil)
})
// Export the video composition to the output URL.
guard let export = AVAssetExportSession(asset: avAsset, presetName: AVAssetExportPresetHighestQuality)
else { fatalError("Can't configure the AVAssetExportSession.") }
export.outputFileType = AVFileType.mov
export.outputURL = output.renderedContentURL
export.videoComposition = composition
export.exportAsynchronously(completionHandler: completion)
}
// MARK: PHPhotoLibraryChangeObserver
extension AssetViewController: PHPhotoLibraryChangeObserver {
func photoLibraryDidChange(_ changeInstance: PHChange) {
// The call might come on any background queue. Re-dispatch to the main queue to handle it.
DispatchQueue.main.sync {
// Check if there are changes to the displayed asset.
guard let details = changeInstance.changeDetails(for: asset) else { return }
// Get the updated asset.
asset = details.objectAfterChanges
// If the asset's content changes, update the image and stop any video playback.
if details.assetContentChanged {
updateImage()
playerLayer?.removeFromSuperlayer()
playerLayer = nil
}
}
}
}
// MARK: PHLivePhotoViewDelegate
extension AssetViewController: PHLivePhotoViewDelegate {
func livePhotoView(_ livePhotoView: PHLivePhotoView, willBeginPlaybackWith playbackStyle: PHLivePhotoViewPlaybackStyle) {
isPlayingHint = (playbackStyle == .hint)
}
func livePhotoView(_ livePhotoView: PHLivePhotoView, didEndPlaybackWith playbackStyle: PHLivePhotoViewPlaybackStyle) {
isPlayingHint = (playbackStyle == .hint)
}
}
参考资料
Browsing and Modifying Photo Albums
NSPredicate
NSSortDescriptor
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