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Reducing storage of similar PNGs by compressing them into a video and retrieving them losslessly--possibility or dumb idea?
My app stores and transports lots of groups of similar PNGs. These aren't compressed well by official algorithms like .lzfse, .lz4, .lzbitmap... not even bz2, but I realized that they are well-suited for compression by video codecs since they're highly similar to one another. I ran an experiment where I compressed a dozen images into an HEVCWithAlpha .mov via AVAssetWriter, and the compression ratio was fantastic, but when I retrieved the PNGs via AVAssetImageGenerator there were lots of artifacts which simply wasn't acceptable. Maybe I'm doing something wrong, or maybe I'm chasing something that doesn't exist. Is there a way to use video compression like a specialized archive to store and retrieve PNGs losslessly while retaining alpha? I have no intention of using the videos except as condensed storage. Any suggestions on how to reduce storage size of many large PNGs are also welcome. I also tried using HEVC instead of PNG via the new UIImage.hevcData(), but the decompression/processing times were just insane (5000%+ increase), on top of there being fatal errors when using async.
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2.1k
Jun ’24
Is the issue of code-theft via decompilation or reverse engineering common for Swift iOS apps? And can I protect a small portion of my code?
I'm a new app developer and I've read through most relevant posts on this topic here and elsewhere. Many of the forum posts here are specific to Objective-C, or old enough to be considered outdated in the fast-moving world of computing. Many of the posts elsewhere are about protecting authentication secrets, which doesn't apply in my case, and a lot are by someone with a product to sell, which I've ignored. My app is 99.9% Swift and I'm not going to store any authentication secrets in the IPA. What I'd like to protect is the core mechanism of my product, which has to be included in the binary and is small (< 10k lines). I want to make it so it's harder to steal the source code than it is to recreate my functionality from scratch, which is difficult even with the app in front of them. From what I gathered, Swift code compiled by Xcode is protected from reverse engineering / decompilation by the following: Symbolization of the app Native builds from Xcode destroys names of variable, functions, etc. Swift code is compiled in such a way that makes stealing harder than Objective-C This should make me feel better, but the threat-level is increasing with the availability of free, commercial-grade decompilers (e.g. Ghidra) and machine learning. The fact that iOS 18 supports a checkm8 (i.e. jailbreakable) device means that decrypting the IPA from memory is still trivial. Questions People talk about stealing authentication secrets via reverse-engineering, but is the same true for mechanisms (i.e. code)? How common is the issue of source-code stealing in iOS apps? Can machine learning be leveraged to make decompilation/reverse engineering easier? Will I get rejected by App Review for obfuscating a small portion of my code?
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2.2k
Jun ’24
How do I stop Tasks from choking up animations?
I'm making a loading screen, but I can't figure out how to make the loading indicator animate smoothly while work is being performed. I've tried a variety of tactics, including creating confining the animation to a .userInitiated Task, or downgrading the loading Task to .background, and using TaskGroups. All of these resulted in hangs, freezes, or incredibly long load times. I've noticed that standard ProgressViews work fine when under load, but the documentation doesn't indicate why this is the case. Customized ProgressViews don't share this trait (via .progressViewStyle()) also choke up. Finding out why might solve half the problem. Note: I want to avoid async complications that come with using nonisolated functions. I've used them elsewhere, but this isn't the place for them.
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1.3k
Aug ’24
How do I implement low-latency streaming between two local iOS devices?
Hello, I'd like to know whether Multipeer Connectivity (MPC) between two modern iOS devices can support cross-streaming of video content at low latency and relatively high resolution. I learned from Ghostbusters that crossing the streams is a bad idea, but I need this for my app so I'm going to ignore their sage advice. The application I have in mind involves one iOS device (A) live-streaming a feed to another iOS device  (B) running the same app. At the same time, B is live streaming its own feed to A. Both feeds don't need to be crystal clear, but there has to be low latency. The sample code for "Streaming an AR Experience" seems to contain some answers, as it's based on MPC (and ARKit), but my project isn't quite AR and the latency seems high. If MPC isn't suitable for this task (as my searches seem to indicate), is it possible to have one device set up a hotspot and link the two this way to achieve my cross-streaming ambitions? This seems like a more conservative method, assuming the hotspot and its client behave like they're wifi peers (not sure). I might start a new thread with just this question if that's more appropriate. A third idea that's not likely to work (for various reasons) is data transfer over a lightning-lightning or lightning-usb-c connection. If I've missed any other possible solutions to my cross-streaming conundrum, please let me know. I've been reading around this subject on this forum as well and would be hugely grateful if Eskimo would grace me with his wisdom.
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3.6k
Feb ’22
Is the code in 'Building a custom peer-to-peer protocol' insecure?
I'm new to Networking, so forgive me if this is a silly question: In the sample code, Building a custom peer-to-peer protocol, TLS is configured as follows: // Create TLS options using a passcode to derive a pre-shared key. private static func tlsOptions(passcode: String) -> NWProtocolTLS.Options { let tlsOptions = NWProtocolTLS.Options() let authenticationKey = SymmetricKey(data: passcode.data(using: .utf8)!) var authenticationCode = HMAC<SHA256>.authenticationCode(for: "TicTacToe".data(using: .utf8)!, using: authenticationKey) let authenticationDispatchData = withUnsafeBytes(of: &authenticationCode) { (ptr: UnsafeRawBufferPointer) in DispatchData(bytes: ptr) } sec_protocol_options_add_pre_shared_key(tlsOptions.securityProtocolOptions, authenticationDispatchData as __DispatchData, stringToDispatchData("TicTacToe")! as __DispatchData) sec_protocol_options_append_tls_ciphersuite(tlsOptions.securityProtocolOptions, tls_ciphersuite_t(rawValue: TLS_PSK_WITH_AES_128_GCM_SHA256)!) return tlsOptions } The sample code touts the connection as secure ("...uses Bonjour and TLS to establish secure connections between nearby devices"), but to my untrained eye it doesn't seem so. My reasoning is as follows: If I adapt this code as-is, so connections between two instances of my app use SymmetricKeys derived from the four-digit passcode, then wouldn't my encryption be easy to break by an adversary who sends 0000...9999 and records corresponding changes in the encryption, exposing my app to all sorts of attacks? The sample uses the passcode to validate the connection (host user shows client user the passcode, which is manually entered), which is a feature I would like to keep in some form or another, which is why this is causing so many headaches. Generally speaking, is there a way to secure a local peer-to-peer connection over Network.framework that doesn't involve certificates? If certificates are the only way, are there good resources you can recommend?
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1.2k
May ’24
Wired data transfer between an app on two iOS/iPadOS devices--Possible or pipe dream?
If two iOS/iPadOS devices have your app opened, is it possible to have the apps send data to each other over a wired connection? E.g. If two iPhone 15s are connected by USB-C, can I get my app in iPhone A to send data to iPhone B and vice-versa? I've been looking around for quite a while now and at this point I just want to know if it's technically feasible.
5
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1.5k
Feb ’24
Compiling the JPEG-XL reference for iOS, or, "Is compiling C++ for iOS really this difficult!?"
I'm trying to add JPEG-XL encoding/decoding capabilities to my app and haven't been able to find a trustworthy pre-compiled version. The only one I've found is in https://github.com/awxkee/jxl-coder-swift. As a result I've been trying to compile my own iOS version from the reference implementation (https://github.com/libjxl/libjxl), having done virtually no compiling before. When I started out, my gut said, "Compiling for a different platform should be easy since it's not like I'm actually writing or modifying the implementation", but the more I research and try, the more doubtful I've become. So far I've figured out it means compiling all the dependencies (brotli, highway, libpng, skcms, etc.) too, but I've also gotten nowhere with them, having tried my hand at modifying cmake toolchains and CMakeList.txt files. As a novice, am I biting off more than I can chew with this? Is the seemingly simple task, "Compile this C++ library for iOS" actually something that freelancers charge huge amounts for? (If so, this makes the free compiled version mentioned above even more questionable) Any help or pointers would be greatly appreciated.
5
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1.5k
Jun ’24
How to limit RealityKit's framerate?
I'm currently weighing moving my project from SpriteKit to RealityKit as a way to future proof it. An important part of the project involves limiting the framerate sprites are displayed at. While RealityKit seems to be set at 60FPS, my project demands a much lower framerate. I should note that I'm not using RealityKit for AR, so there's no camera passthrough to worry about. Is there a way to limit RealityKit's rendering framerate?
4
1
1.8k
Aug ’22
[iOS 26] Can no longer detect whether iPhone has notch
I'm currently using the extension below to determine whether an iPhone has a notch so I can adjust my UI accordingly. extension UIDevice { var hasNotch: Bool { if userInterfaceIdiom == .phone, let window = (UIApplication.shared.connectedScenes .compactMap { $0 as? UIWindowScene } .flatMap { $0.windows } .first { $0.isKeyWindow }) { return window.safeAreaInsets.bottom > 0 } return false } } (Adapted from https://stackoverflow.com/questions/73946911/how-to-detect-users-device-has-dynamic-island-in-uikit) This no longer works in iOS 26, and I have yet to find a similar method that works. Does anyone have any fixes?
4
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191
Oct ’25
Is it possible to compile images into an APNG using Swift?
Hello, I'm wondering if there is a way to programmatically write a series of UIImages into an APNG, similar to what the code below does for GIFs (credit: https://github.com/AFathi/ARVideoKit/tree/swift_5). I've tried implementing a similar solution but it doesn't seem to work. My code is included below I've also done a lot of searching and have found lots of code for displaying APNGs, but have had no luck with code for writing them. Any hints or pointers would be appreciated. func generate(gif images: [UIImage], with delay: Float, loop count: Int = 0, _ finished: ((_ status: Bool, _ path: URL?) -> Void)? = nil) { currentGIFPath = newGIFPath gifQueue.async { let gifSettings = [kCGImagePropertyGIFDictionary as String : [kCGImagePropertyGIFLoopCount as String : count]] let imageSettings = [kCGImagePropertyGIFDictionary as String : [kCGImagePropertyGIFDelayTime as String : delay]] guard let path = self.currentGIFPath else { return } guard let destination = CGImageDestinationCreateWithURL(path as CFURL, __UTTypeGIF as! CFString, images.count, nil) else { finished?(false, nil); return } //logAR.message("\(destination)") CGImageDestinationSetProperties(destination, gifSettings as CFDictionary) for image in images { if let imageRef = image.cgImage { CGImageDestinationAddImage(destination, imageRef, imageSettings as CFDictionary) } } if !CGImageDestinationFinalize(destination) { finished?(false, nil); return } else { finished?(true, path) } } } My adaptation of the above code for APNGs (doesn't work; outputs empty file): func generateAPNG(images: [UIImage], delay: Float, count: Int = 0) { let apngSettings = [kCGImagePropertyPNGDictionary as String : [kCGImagePropertyAPNGLoopCount as String : count]] let imageSettings = [kCGImagePropertyPNGDictionary as String : [kCGImagePropertyAPNGDelayTime as String : delay]] guard let destination = CGImageDestinationCreateWithURL(outputURL as CFURL, UTType.png.identifier as CFString, images.count, nil) else { fatalError("Failed") } CGImageDestinationSetProperties(destination, apngSettings as CFDictionary) for image in images { if let imageRef = image.cgImage { CGImageDestinationAddImage(destination, imageRef, imageSettings as CFDictionary) } } }
3
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1.8k
Mar ’24
How to attribute/credit Apple Fonts added to app?
My app lets users create things with text, and I've included Apple fonts so users can format their text with them. These were fonts I found in the Font Book app that comes with macOS. My assumption is that these, like the San Francisco font, can be distributed with apps. Do I need to attribute these fonts to their creators and publish a license in my "About" page? If so, where do I find the license(s) and what is the proper way of publishing them? Is there anything else I should know? Please let me know if this should've been posted under a different topic and tag
Topic: Design SubTopic: General Tags:
3
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1.2k
Jan ’25
Scrolling sticker browser on a Messages App sheet causes sheet to move
As someone who learned Swift via SwiftUI, UIKit is completely alien to me, so I apologize if this is actually a very simple issue. I have a Messages extension that includes a sticker browser within it. In this extension, the MSMessagesAppViewController hosts a SwiftUI View, which in turn hosts a UIViewRepresentable version of MSStickerBrowserView. The whole Messages App sheet moves with an upward drag, and can switch to its expanded mode, whenever the browser is scrolled to the top (first sticker is at top left), but it doesn't budge when the browser is scrolled to the other end when it should allow the sheet to move upward with the drag. It seems something is reversed within the gesture priority management that allows a sheet to be moved in the appropriate direction when a contained scrollview is at the appropriate end. Things I've tried while reaching a diagnosis include: Limiting the presentation style to compact (the modal still moves, but never succeeds in changing) Adding competing highPriorityGestures in the SwiftUI view, set at various locations Inserting a rectangle with allowsHitTesting(false) beneath the browser Changing firstResponder statuses for all relevant views Changing GestureResponder priorities (there are no gesture responders in all views examined) Things I've considered but don't have the technical skills to implement: Have the view scroll a little downwards programmatically (like what can be done via ScrollViewReader in SwiftUI), but I have no idea how this can be done via MSStickerBrowserView or UIKit in general. Maybe the MSStickerBrowserView thinks its always in the expanded state (when the sheet is expanded, the end-drags work fine). If this is the case, if there's a way to either fix this misconception (via controller's didTransition) or do away with end drags in general, the problem should go away. Any pointers would be greatly appreciated!
2
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1k
Jan ’24
[iOS 17.4, XCode 15.3] Previously working NWConnection for peer-to-peer connection now permanently stuck on "Preparing"
After updating my devices to iOS/iPadOS 17.4, and XCode to 15.3, Network framework peer-to-peer connections have stopped working entirely. The system was working fine before and the code has not been changed. On the client side (NWBrowser) the server (NWListener) can be seen, but upon attempting to establish a connection the client-side NWConnection.State gets permanently stuck at .preparing. NWConnection.stateUpdateHandler doesn't enter any other state. It doesn't seem as though it's taking a long time to prepare; it's just stuck. This situation occurs across multiple connection modes (wired, common wifi, separate wifi). Additional information I didn't participate in the 17.4 beta and RC The code in "Creating a custom peer-to-peer protocol" works--this code forms the basis of my code
2
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1.5k
Mar ’24
[WatchOS 11, Xcode 16] Can't get watch to appear in Xcode
This morning I bought my first-ever Apple Watch for the sole purpose of development and proceeded to spend six hours failing at the first step of development: getting the device to enter developer mode and connect to Xcode. Since I'm not seeing any WatchOS 11 posts on this issue, it might just be me. This is why I'm making a new thread that's specific to WatchOS 11, Xcode 16, and maybe Series 10. Some particulars for my case: Overall __Followed Xcode 16.0 documentation On a watchOS device that you use for development, go to Settings > Privacy > Developer Mode. To toggle Developer mode, use the Developer Mode switch. To pair an Apple Watch to a Mac, connect its companion iPhone to the Mac with a cable, and ensure that the iPhone is paired for development. After this step, follow any instructions on the Apple Watch to trust the Mac. When paired through an iPhone running iOS 17 or later, Xcode connects to the Apple Watch over Wi-Fi __Tried all the folk remedies listed in the (many) previous posts on enabling development mode and connecting to Xcode iOS 18.0 __In developer mode __Connected to macOS via USB, trusts computer WatchOS 11.0 __Prompt to trust computer appears and trust is established __‘Developer Mode’ list item never appears at end of the ‘Privacy’ menu under ‘Settings’ __‘Developer’ item sometimes appears at the end of ‘Settings’ Despite never having seen or toggled ‘Developer Mode’ under ‘Privacy’ Persists across reboots Possible that WatchOS 11 eliminated the item under Settings > Privacy? If so, documentation not up to date Xcode 16.0 __Watch never appears under ‘Manage Run Destinations’ After installing sample app to phone, then attempting to install WatchOS app via iOS Watch app, “Cannot install at this time” alert appears App icon appears on watch, and tapping on it leads to an alert with, “This app cannot be installed because its integrity could not be verified”, despite wi-fi working Watch apps for other apps (e.g. Apple Store) can be successfully installed via iOS Watch app Above suggests the watch isn't truly in developer mode despite Settings > Developer appearing and persisting across reboots __The network path from Xcode to WatchOS should be clear Reconfigured router such that devices on the same network can talk to each other iPad and iPhone appear with network icon when not connected via cable and Xcode can run code on them Watch on same network as iPad and iPhone macOS 15.0 __Due to security policy, cannot use Wi-Fi (disabled both physically and via sudo /usr/sbin/networksetup -setnetworkserviceenabled 'Wi-Fi' off) Possible that Xcode can only establish a connection to WatchOS via Wi-Fi and not via ethernet bridged to wifi. If so, a confirmation would be hugely helpful. This is currently my prime suspect. Wi-fi cannot be re-enabled, so I'm trying workarounds like connecting watch to phone's hotspot (doesn't work) and somehow using phone to provide network to the Mac. __Due to security policy, firewall configured to block all incoming connections Shouldn't be an issue since Xcode doesn't need incoming connections to see non-watch devices __Due to security policy, mDNSResponder and mDNSResponderHelper disabled Also shouldn't be an issue, but including just in case
2
2
2.3k
Sep ’24
How would you make a View that magnifies the View(s) beneath it?
I need a magnifying glass function for one of my SwiftUI Views, but can't find a way to implement it as needed. I found a Youtube video where the author renders the view twice, overlaying the second over the first, then scaling and masking it to create the illusion of magnification, but this is expensive and doesn't work in many cases where more complex views are presented (e.g. a LazyVGrid). I've also explored continually capturing partial screenshots and scaling them up to create the illusion of magnification, but there's no straightforward way to achieve this with SwiftUI without getting into the messiness of UIViewRepresentables. Any help would be greatly appreciated
2
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513
Oct ’24