i have an app that works with API JSON response. Just retrieving a simple array of items. Each item has an url with a high-res image. I'm using Kingfisher to get this images and resize to my ImageView size (that placed on my MainView)
//MainViewController
itemImageMainVC.kf.setImage(
with: URL(string: itemModel.artImage),
options: [
.processor(DownsamplingImageProcessor(size: itemImageMainVC.bounds.size) >> RoundCornerImageProcessor(cornerRadius: 16, targetSize: itemImageMainVC.bounds.size)),
.scaleFactor(UIScreen.main.scale),
.transition(.fade(0.2)),
.cacheOriginalImage
])
Everything is fine here, i've got my images on my MainView inside TableView, and they cached well. BUT! If i try to open and display the same images, but with different sizes on the SecondView, i see the same transition animation on the SecondView, so i guess that they started to download again when they shouldn't.
//SecondViewController
itemImageSecondVC.kf.setImage(
with: URL(string: itemModel.artImage),
options: [
.processor(DownsamplingImageProcessor(size: itemImageSecondVC.bounds.size) >> RoundCornerImageProcessor(cornerRadius: 16, targetSize: itemImageSecondVC.bounds.size)),
.scaleFactor(UIScreen.main.scale),
.transition(.fade(0.2)),
.cacheOriginalImage
])
itemImageMainVC and itemImageSecondVC have different sizes.
What i'm doing wrong? I just want to download/display images on the MainView and instantly show them when i open SecondView, without re-downloading
Lets try to use the cacheKey, it should be the last path component (or event the absoluteUrlString) from your image url or something that is unique.
let resource = ImageResource(downloadURL: url, cacheKey: url.lastPathComponent)
self.imageView.kf.setImage(with: resource, placeholder: UIImage(named: "placeholder-image"), options: nil, progressBlock: nil) { (result) in
switch result {
case .success(_):
// Success case
case .failure(_):
// Failed case
}
}
Related
When I use PHImageManager() to retrieve an image from the photo library, the image is converted from a jpeg image to a png image, and the image is degraded.
How can I retrieve the image without image degradation?
Is it a standard specification that the extension is changed from jpeg to png?
If anyone knows, please respond.
Here is a sample code I made.
img is returned as png.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let assets: PHFetchResult = PHAsset.fetchAssets(with: .image, options: nil)
let mg: PHImageManager = PHImageManager()
guard let asset = assets.lastObject else {
return
}
let options = PHImageRequestOptions()
options.isNetworkAccessAllowed = true
options.deliveryMode = .highQualityFormat
mg.requestImage(for: asset, targetSize: PHImageManagerMaximumSize, contentMode: .aspectFit, options: options, resultHandler: { image, info in
let img = image
})
}
}
When requesting a high quality image, the result handler of requestImage may be called initially with a low quality version of the image, then later called again with the high quality version.
You can check this by inspecting the PHImageResultIsDegradedKey of the info dictionary parameter of the result handler, for example:
mg.requestImage(for: asset, targetSize: PHImageManagerMaximumSize, contentMode: .aspectFit, options: options, resultHandler: { image, info in
if info?[PHImageResultIsDegradedKey] as? Bool == true {
print("Degraded image returned, will wait for high quality image")
return
}
let img = image
})
From the documentation for PHImageManager.requestImage:
[...] Photos may call your result handler block more than once. Photos first calls the block to provide a low-quality image suitable for displaying temporarily while it prepares a high-quality image. (If low-quality image data is immediately available, the first call may occur before the method returns.) When the high-quality image is ready, Photos calls your result handler again to provide it. If the image manager has already cached the requested image at full quality, Photos calls your result handler only once. The PHImageResultIsDegradedKey key in the result handler’s info parameter indicates when Photos is providing a temporary low-quality image.
My code as below. It is sending duplicated photos 1) high quality and 2) low quality. Just want to understand why this library is doing that ?
PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: .aspectFit, options: nil) { result, info in
guard let image = result else {
return
}
self.sendPhoto(image)
}
FIXed by to force the options to send a quality
fileprivate func imageRequestOptions() -> PHImageRequestOptions {
let requestOption = PHImageRequestOptions()
requestOption.deliveryMode = .highQualityFormat
return requestOption
}
PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: .aspectFit, options: self.imageRequestOptions()) { result, info in
guard let image = result else {
return
}
self.sendPhoto(image)
print("sendPhoto iOS 11.0 * asset")
}
From the document of Apple
For an asynchronous request, Photos may call your result handler block more than once. Photos first calls the block to provide a low-quality image suitable for displaying temporarily while it prepares a high-quality image. (If low-quality image data is immediately available, the first call may occur before the method returns.) When the high-quality image is ready, Photos calls your result handler again to provide it. If the image manager has already cached the requested image at full quality, Photos calls your result handler only once. The PHImageResultIsDegradedKey key in the result handler’s info parameter indicates when Photos is providing a temporary low-quality image.
You can use this method for both photo and video assets—for a video asset, an image request provides a thumbnail image or poster frame.
Maybe this is business of them. I think we should note with this case
I call the function. Alright
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
let index = viewControllers?.index(of: viewController)
if index == 2 {
let layout = UICollectionViewFlowLayout()
let photoSelectorController = PhotoSelectorController(collectionViewLayout: layout)
let navController = UINavigationController(rootViewController: photoSelectorController)
present(navController, animated: true, completion: nil)
return false }
return true
}
Photos not showing on first time
I have all of the right things asking for permission and everything..
I then call for the images with these functions. It works, but the second time I hit the button after canceling posting a post..
I'm not sure how to get the images from the library for the first call.
After that it works like a charm, but most users have been telling me this isn't a good experience , if they have to try twice.
I'm trying to reduce friction in the app usage.
It should show the pictures right after the user "Allows" the app access to the pictures so they can post, but I'm not sure what I'm doing wrong for it to show the pictures soon as someone grants access.
var selectedImage: UIImage?
var images = [UIImage]()
var assets = [PHAsset]()
fileprivate func assetsFetchOptions() -> PHFetchOptions {
let fetchOptions = PHFetchOptions()
fetchOptions.fetchLimit = 100
let sortDescriptor = NSSortDescriptor(key: "creationDate", ascending: false)
fetchOptions.sortDescriptors = [sortDescriptor]
return fetchOptions
}
fileprivate func fetchPhotos() {
let allPhotos = PHAsset.fetchAssets(with: .image, options: assetsFetchOptions())
DispatchQueue.global(qos: .background).async {
allPhotos.enumerateObjects { (asset, count, stop) in
print(asset)
let imageManager = PHImageManager.default()
let targetSize = CGSize(width: 200, height: 200)
let options = PHImageRequestOptions()
options.isSynchronous = true
imageManager.requestImage(for: asset, targetSize: targetSize, contentMode: .aspectFit, options: options, resultHandler: { (image, info) in
if let image = image {
self.images.append(image)
self.assets.append(asset)
if self.selectedImage == nil {
self.selectedImage = image
}
}
if count == allPhotos.count - 1 {
DispatchQueue.main.async {
self.collectionView?.reloadData()
}
}
})
}
}
}
If you fetchAssets before the user grants privacy access to your app, you'll get a PHFetchResult that's empty.
However, if before making that fetch you register as a photo library observer, you'll get a photoLibraryDidChange callback as soon as the user approves privacy access for the app... from that callback you can access an updated version of your original fetch result (see changeDetails(for:)) that has all of the assets your fetch should have found. Then you can tell your UI to update and display those assets. (This is how Apple's canonical PhotoKit example code works.)
Also, once you have a populated fetch result, please don't request thumbnails for the whole thing the way you're doing.
Users commonly have photo libraries with tens of thousands of assets, many of which are in iCloud and not on the local device. If you synchronously get all thumbnails, you'll take forever, use tons of memory and CPU resources, and generate all kinds of network traffic (slowing things down even more) for resources your user may never see.
PhotoKit is designed to allow easy use in conjunction with UI elements like UICollectionView. A collection view only loads cells that are currently (or soon to be) on screen, even if you've told it you have zillions of items in your collection — similarly, you can request thumbnails only for assets that are visible in your collection view. Wherever you have your per-cell UI setup logic is where you should have your PHImageManager request. (Again, this is what the canonical PhotoKit example code does.)
You can optimize even further by "preheating" the thumbnail fetch/generation process for assets that are soon to be onscreen. And then by managing your "preheating" to cancel such work in progress when further UI updates (e.g. fast scrolling of large collection) make it unnecessary. PHCachingImageManager does this. (And yet again, it's what the canonical Apple sample does. Actually, that sample's a bit out of date, and as such does more work than it needs to on this front — it does its own calculation of what cells are just outside the scroll rect, but since iOS 10 the UICollectionViewDataSourcePrefetching protocol manages that for you.)
After update to iOS 11, photo assets now load slowly and I get this message in console:
[ImageManager] Unable to load image data,
/var/mobile/Media/DCIM/103APPLE/IMG_3064.JPG
I use static function to load image:
class func getAssetImage(asset: PHAsset, size: CGSize = CGSize.zero) -> UIImage? {
let manager = PHImageManager.default()
let option = PHImageRequestOptions()
option.isSynchronous = true
var assetImage: UIImage!
var scaleSize = size
if size == CGSize.zero {
scaleSize = CGSize(width: asset.pixelWidth, height: asset.pixelHeight)
}
manager.requestImage(for: asset, targetSize: scaleSize, contentMode: .aspectFit, options: option) { (image, nil) in
if let image = image {
assetImage = image
}
}
if assetImage == nil {
manager.requestImageData(for: asset, options: option, resultHandler: { (data, _, orientation, _) in
if let data = data {
if let image = UIImage.init(data: data) {
assetImage = image
}
}
})
}
return assetImage
}
Request image for asset usually always succeeds, but it prints this message. If I use requestImageData function only, there is no such message, but photos made with Apple camera lose their orientation and I get even more issues while loading big amount of images (I use image slideshow in my app).
Apple always sucks when it comes to updates, maybe someone got a solution how to fix this? It even fails to load an asset, when there is a big list of them in user camera. Switching to requestImageData is not an option for me as it brings nil data frequently now.
I would like to point out, that I call this function only once. It is not used in UITableView etc. I use other code for thumbs with globally initialised manager and options, so assets are definitely not nil or etc.
I call this function only when user clicks at certain thumb.
When gallery has like 5000 photos, maybe connection to assets is just overloaded and later it can't handle request and crashes?
So many questions.
Hey I was having the warning as well and here is what worked for me.
Replacing
CGSize(width: asset.pixelWidth, height: asset.pixelHeight)
by
PHImageManagerMaximumSize in requestImage call
removed the warning log 🎉
Hope this helps,
I had the same problem. Though this did not completely solve it, but it definitely helped.
option.isNetworkAccessAllowed = true
This helps only on the devices where Optimise iPhone Storage option for Photos app has been turned on.
Your code has some serious issues. You are saying .isSynchronous = true without stepping into a background thread to do the fetch. That is illegal and is what is causing the slowness. Plus, you are asking for a targetSize without also saying .resizeMode = .exact, which means you are getting much bigger images than you are asking for.
However, the warning you're seeing is irrelevant and can be ignored. It in no way signals a failure of image delivery; it seems to be just some internal message that has trickled up to the console by mistake.
This seems to be a bug with iOS 11, but I found I could work around by setting synchronous option false. I reworked my code to deal with the async delivery. Probably you can use sync(execute:) for quick fix.
Also, I believe the problem only occurred with photos delivered by iCloud sharing.
You can try method "requestImageData" with following options. This worked for me in iOS 11.2 (both on device and simulator).
let options = PHImageRequestOptions()
options.deliveryMode = .highQualityFormat
options.resizeMode = .exact
options.isSynchronous = true
PHImageManager.default().requestImageData(for: asset, options: options, resultHandler: { (data, dataUTI, orientation, info) in
I have been unable to find enough documentation to get started on a Photos Project extension (available in High Sierra).
How do I retrieve what a user has selected (like how Apple does it with their Prints extension), and display that in my extension's view?
I think you just want to look at PHProjectInfo which is passed to you in beginProject. That's where you get the real context of what was selected. For example:
let sections = projectInfo.sections
guard let firstContentSection = sections.first(where: { section in section.sectionType == .content }),
let firstContents = firstContentSection.sectionContents.first
You then need to convert the cloud identifiers to local ones for fetching:
localIdentifiers = context.photoLibrary.localIdentifiers(for: cloudIdentifiers)
From there, you can fetch the actual PHAssets:
let fetchResult = PHAsset.fetchAssets(withLocalIdentifiers: localIdentifiers, options: nil)
For any PHAsset, when you want the image you want to use PHImageManager:
imageManager.requestImage(for: asset, targetSize: targetSize, contentMode: PHImageContentMode.aspectFit, options: nil)