To create signatures for human faces and compare the similarities, I'm using ARKit's captureImage from ARFrame which is derived from the front facing camera with ARFaceTrackingConfiguration.
However, compared to using the Vision and AVFoundation frameworks, the quality of the signature analysis is significantly impacted by the captureImage's low resolution. The resolution of the capturedImage in ARKit is just 640x480, according to capturedDepthData even though the video format is set to the highest resolution.
let configuration = ARFaceTrackingConfiguration()
if let videoFormat = ARFaceTrackingConfiguration.supportedVideoFormats.sorted(by: { ($0.imageResolution.width * $0.imageResolution.height) < ($1.imageResolution.width * $1.imageResolution.height) }).last {
configuration.videoFormat = videoFormat
}
I tried using captureHighResolutionFrame and as well as change the video format:
if let videoFormat = ARFaceTrackingConfiguration.recommendedVideoFormatForHighResolutionFrameCapturing {
configuration.videoFormat = videoFormat
}
However, according to the documentation:
The system delivers a high-resolution frame out-of-band, which means that it doesn't affect the other frames that the session receives at a regular interval
The asynchronous nature of taking the high resolution images seems to result alternating between the standard captured image and the high resolution images rather than replacing the regular captured images. This is a concern because, depending on the size variations, displayTransform and CGAffineTransform must be used in different ways to scale the images.
Not only that I need to able to use the frames continuously at either 30 fps or 60 fps, as they're produced rather than taking pictures occasionally, which the captureHighResolutionFrame method seems to be designed for considering the shutter sound.
In order to use the captured image, I'm currently transforming it in the following way
let image: CIImage = CIImage(cvImageBuffer: imageBuffer)
let imageSize: CGSize = CGSize(width: CVPixelBufferGetWidth(imageBuffer), height: CVPixelBufferGetHeight(imageBuffer))
let normalizeTransform: CGAffineTransform = CGAffineTransform(scaleX: 1.0 / imageSize.width, y: 1.0 / imageSize.height)
let flipTransform: CGAffineTransform = metadata.orientation.isPortrait ? CGAffineTransform(scaleX: -1, y: -1).translatedBy(x: -1, y: -1) : .identity
guard let viewPort: CGRect = face.viewPort else { return nil }
let viewPortSize: CGSize = viewPort.size
guard let displayTransform: CGAffineTransform = face.arFrame?.displayTransform(for: metadata.orientation, viewportSize: CGSize(width: viewPortSize.width, height: viewPortSize.height)) else {
return nil
}
let scaleX: CGFloat = viewPortSize.width
let scaleY: CGFloat = viewPortSize.height
let viewPortTransform: CGAffineTransform = CGAffineTransform(scaleX: scaleX, y: scaleY)
let scaledImage: CIImage = image
.transformed(by: normalizeTransform
.concatenating(flipTransform)
.concatenating(displayTransform)
.concatenating(viewPortTransform)
)
.cropped(to: viewPort)
Ovis
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Post
Replies
Boosts
Views
Activity
I'm getting what seems to be a dynamic linker error, but can't seem to resolve it.
dyld[541]: Library not loaded: @rpath/TCore.framework/TCore
Referenced from: /private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/FaceSDK.framework/FaceSDK
Reason: tried: '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/FaceSDK.framework/Frameworks/TCore.framework/TCore' (no such file), '/usr/lib/swift/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/usr/lib/swift/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/System/Library/Frameworks/TCore.framework/TCore' (no such file)
Library not loaded: @rpath/TCore.framework/TCore
Referenced from: /private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/FaceSDK.framework/FaceSDK
Reason: tried: '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/FaceSDK.framework/Frameworks/TCore.framework/TCore' (no such file), '/usr/lib/swift/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/NavigationApp.app/Frameworks/TCore.framework/TCore' (no such file), '/private/var/containers/Bundle/Application/EEBCD2F1-3A25-4BCE-A151-04EC09374288/Navigatio
So far I've tried embedding it and linking it in both "General" and "Build Phase" of the Settings. I've tried setting Dynamic Library Install Name Base to @rpath as well as setting Always Embed Swift Standard Libraries to YES, but none seem to work.
Broadly speaking, what is the sequence of events that happens from the moment UIEvent is created, particularly the UITouch-related event? I'm getting conflicting information from various places.
One article is saying:
UITouch/UIEvent is created
UIApplication.shared.sendEvent() sends the event to a queue
The event goes directly to the view's UIGestureRecognizer or UIResponder
It doesn't mention when the hit-tests from UIWindow all the way up to the touched view happens.
Second article says:
An event is created
The hit-test is performed on the view that was touched
UIApplication.shared.sendEvent(\_:)
UIWindow.sendEvent(\_:)
UIGestureRecognizer
Hit-test happens again?
UIResponder
Another article says:
An event is created
UIApplication manages the queue of UIEvents
UIWindow performs the hit test. I'm guessing this is done by UIWindow.sendEvent(\_:)?
UIApplication.shared.sendEvent(\_:) sends the event to the first responder
The event is handled by the gesture recognizer or the responder
Finally, another book I'm reading is saying:
An event is created
The event is handed to an instance of UIApplication through UIApplication.shared.sendEvent(\_:)
UIWindow gets the event through UIWindow.sendEvent(\_:)
UIWindow performs the hit-tests on the view hierarchy as well as the UIResponder
I'm ok with some of these resources having incomplete information. What frustrates me is how some of them have completely different orders. So far, I'm certain that an instance of UIEvent and UITouch are created first and UIGestureRecognizer and UIResponder are reached last, but that's about it.
What I'm confused about is:
When do the hit-tests of the view hierarchy happen?
What exactly does UIApplication.shared.sendEvent(\_:) do? The definition says "Dispatches an event to the appropriate responder objects in the app", but this means that the UIEvent has to already know the touched view associated with it, which means this method has to be invoked after the hit-tests. But, none of the above resources say that UIApplication.shared.sendEvent(\_:) happens AFTER the hit-tests.
The definition of UIWindow.sendEvent(\_:) says that it's for dispatching the event to a view (and not a responder like UIApplication.shared.sendEvent(\_:)). I'm not exactly sure what the difference is. And does this happen before or after the hit-tests?
What is this "queue" they keep referring to? Is it the queue to be sent to the instance of UIApplication or the responders or to UIWindow or to perform hit-tests?
P.S. for some reason I'm unable to post any of the links to the articles and am getting "This URL can't be included in your post. Please remove it to continue".
I'm having difficult time understanding the practical usage of the intrinsic content size, especially the cases when you have to override the existing intrinsic size. It seems like using the widthAnchor and the heightAnchor seem to resolve what the intrinsic content size is trying to solve.
For example if I wanted a certain intrinsic size:
class CustomView: UIView {
		override var intrinsicContentSize: CGSize {
				return CGSize(width: 200, height: 100)
		}
}
I could achieve the same effect by using the Autolayout anchors:
NSLayoutConstraint.activate([
		view.heightAnchor.constraint(equalToConstant: 100),
		view.widthAnchor.constraint(equalToConstant: 200)
])
When the stack view are required to have a size, you can also provide it with the anchors.
Only two use cases I found it to be helpful is if you wanted to manipulate the existing original intrinsicContentSize:
class CustomView: UIView {
		override var intrinsicContentSize: CGSize {
				let originalSize = super.intrinsicContentSize
				return CGSize(width: originalSize.width + 200, height: 100)
		}
}
But, I feel like intrinsicContentSize offers far more than simply using it as margins.
The second use case is when you can change the priority by using either setContentCompressionResistancePriority(_:for:) or setContentHuggingPriority(_:for:) to indicate how to respond to the changes in its superview dynamically.
I'm trying to implement additionalSafeAreaInsets, similar to the example from the Apple's documentation, - https://developer.apple.com/documentation/uikit/uiview/positioning_content_relative_to_the_safe_area but the child view controller is not respecting the additional insets:
import UIKit
import PlaygroundSupport
class MyVC: UIViewController {
		var leftView: UIView!
		let secondVC = SecondVC()
		
		override func viewDidLoad() {
				super.viewDidLoad()
				leftView = UIView(frame: CGRect(origin: .zero, size: .init(width: 50, height: self.view.bounds.size.height)))
				leftView.backgroundColor = .blue
				self.view.addSubview(leftView)
		}
		
		override func viewDidAppear(_ animated: Bool) {
				super.viewDidAppear(true)
						
				var newSafeArea = UIEdgeInsets()
				if let sideViewWidth = leftView?.bounds.size.width {
						newSafeArea.left += sideViewWidth
				}
				
				print(newSafeArea)
				
				addChild(secondVC)
				secondVC.view.frame = self.view.safeAreaLayoutGuide.layoutFrame
				self.view.addSubview(secondVC.view)
				secondVC.didMove(toParent: self)
				secondVC.additionalSafeAreaInsets = newSafeArea
		}
}
class SecondVC: UIViewController {
		override func viewDidLoad() {
				super.viewDidLoad()
				self.view.backgroundColor = .yellow
		}
}
PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = MyVC()
The expectation is that the left column view (leftView) is juxtaposed to a child view controller (childVC) within a root view controller (MyVC), but the child view controller simply takes up the entire main view.
I've been trying different ways on the Playground, but the margins are not being implemented. I'm trying to understand the proper way of using UIEdgeInsets (and NSDirectionalEdgeInsets).
My expectation is that the super view should have margins of specified size and the subview should be within that margin, sort of like an invisible border.
Following didn't show any margins for the superview:
import UIKit
import PlaygroundSupport
let rootView = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
rootView.layoutMargins = UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100)
let subview = UIView()
subview.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
subview.widthAnchor.constraint(equalToConstant: 100),
subview.heightAnchor.constraint(equalToConstant: 100)
])
subview.backgroundColor = .red
rootView.addSubview(subview)
PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = rootView
I've also tried with:
rootView.layoutMargins.top = 100
or instead of Autolayout:
let subview = UIView(frame: CGRect(origin: .zero, size: .init(width: 100, height: 100)))
No need to mention NSDirectionEdgeInsets didn't work:
rootView.directionalLayoutMargins = NSDirectionalEdgeInsets(top: 100, leading: 100, bottom: 100, trailing: 100)
I tried it with a view controller, but still futile:
class MyVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let rootView = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
rootView.layoutMargins = UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100)
self.view.addSubview(rootView)
let subview = UIView()
subview.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
subview.widthAnchor.constraint(equalToConstant: 100),
subview.heightAnchor.constraint(equalToConstant: 100)
])
subview.backgroundColor = .red
rootView.addSubview(subview)
}
}
What am I doing wrong?
When an app launches, UIApplicationMain creates the UIWindowScene which is used to instantiate the window. A view controller is then instantiated and assigned to the rootViewController property of the window.
In other words:
UIWindowScene -> window -> rootViewController
As far as I understand, there is usually one scene to which view controllers can be added (although you can create more than one scene).
But, when I see a storyboard, I see View Controller Scene per view controller. Are these scenes different from the window scene? If so, are these properties of UIWindowScene or the window?
As far as I understand, a UIControl subclass maintains an internal dispatch table for the target-action pairs. When a user event occurs, a control finds the appropriate target and its matching action to call. And it does this by climbing the UIResponder hierarchy until it finds the right target and the action. Why wouldn't you specify the target? Is it so that the control becomes reusable?
I have a few questions regarding the proxy objects of a NIB file, specifically in regards to the File's Owner object.
The File's Owner object is a placeholder instance which represents some instance of a class outside the NIB file that will soon substitute this tentative instance. From what I understand, NIB files and XIB files are lazy loaded. Does this mean the placeholder instance (before it is substituted by the "real" class's instance) is already an instance (not a type) even before the NIB files are called?
What is this placeholder instance an instance of?
The File's Owner object is configured with a custom class, say ViewController. Why do you have to specify the owner again when you load this NIB file? Bundle.main.loadNibNamed("SomeNIBFile", owner: self )
When you build your project, what makes a framework usable is a two-stage process. You first import the framework's header in order to compile and it must link to the framework's binary so that they can interact with each other during runtime.
But, how am I allowed to use the Apple's frameworks by only importing them and not linking them in to your target in the Build Phase ?
For example, I've seen some people manually add MapKit to the Link Binary With Libraries section of Build Phase , but it works perfectly fine without doing so. What is the rule of thumb? Do I ever have to do this process manually? Do I have to make sure to do this for the 3rd party frameworks?
I'm having difficulty understanding the true cost of using the public container of CloudKit. I understand that the private container's limit counts towards the personal iCloud storage and the public container towards the separate limit, but I'm curious about the cost of the public container. Virtually every website I've visited to research this refers the Apple's calculator. This is the few information I was able to scrape. Basically, the public container is free to use up until a certain limit and then you get charged for anything extra. The limit is as follows:
Asset Storage: 250 MB
Database Storage: 2.5 MB
Data Transfer: 50 MB
Requests Per Second: 10 per 100k users
Overage Fees Asset storage$0.03/GB
Database storage$3.00/GB
Data transfer$0.10/GB
Requests per sec$100 per 10 requests
This is what Apple's website says about these numbers:
Limits are calculated and based on an average usage across the total number of active users per month. Users must have active container usage within the last 16 months. If your account exceeds its free limits of public storage, data transfer, or requests per second, overage charges may apply. Your app will not get additional free allowances by using multiple containers
I have a few questions and any help would be appreciated: Is the 50 MB transfer limit per month or per transfer?
I'm not sure if I'm understanding the 2.5 MB of the database storage limit correctly because that's pretty minuscule.
Does the user bear the cost or the developer?
If former, what happens when the limit is reached? Does the iOS or iPadOS inform the user or does the app have to notify the user like the In App Purchase? Does the app have to inform the user before using the app that there is a limit because I've never seen any of the apps do warning me of the public container usage limit.
If latter, is there a way to set up an In-app purchasing option and have the public container access as a premium feature?
I'm attempting to write to the public container of CloudKit, but I keep getting the error message:
CKError 0x281ff9ec0: "Network Unavailable" (3/NSURLErrorDomain:-1009); "The Internet connection appears to be offline." only when I'm accessing the container through the cellular network. When I try on a wifi network, however, it works perfectly fine and can confirm the presence of the uploaded data on the dashboard. There is absolutely nothing wrong with the cellular connectivity of my device.
let publicCloudDatabase = CKContainer.default().publicCloudDatabase
let operation = CKModifyRecordsOperation(recordsToSave: [exampleRecord], recordIDsToDelete: nil)
let operationConfiguration = CKOperation.Configuration()
operationConfiguration.allowsCellularAccess = true
operationConfiguration.qualityOfService = .userInitiated
operation.configuration = operationConfiguration
operation.perRecordProgressBlock = {(record, progress) in
		print(progress)
}
operation.perRecordCompletionBlock = {(record, error) in
		print("Upload complete")
}
publicCloudDatabase.add(operation)
publicCloudDatabase.save(exampleRecord) { [unowned self] record, error in
		if let error = error {
				print("public cloud database error: \(error)")
		} else {
				print("Sucessfully uploaded to Public Cloud DB")
		}
}
I've tried the different quality of service, like userInteractive, but still doesn't work.
I initialize the container in AppDelegate.swift with the standard code:
lazy var persistentCloudKitContainer: NSPersistentCloudKitContainer = {
let container = NSPersistentCloudKitContainer(name: "Example")
guard let description = container.persistentStoreDescriptions.first else {
fatalError("Could not retrieve a pesistent store description")
}
let options = NSPersistentCloudKitContainerOptions(containerIdentifier: "iCloud.com.noName.Example")
description.cloudKitContainerOptions = options
do {
try container.initializeCloudKitSchema()
} catch {
print("Initialize error: \(error)")
}
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
The Security Role on the dashboard shows that the creator can both read and write.
Xcode: Version 12.0 beta 6
iOS: 14.0