Hello!
I’m experiencing a crash in my iOS/iPadOS app related to a CALayer rendering process. The crash occurs when attempting to render a UIImage on a background thread. The crashes are occurring in our production app, and while we can monitor them through Crashlytics, we are unable to reproduce the issue in our development environment.
Relevant Code
I have a custom view controller that handles rendering CALayers onto images. This method creates a CALayer on the main thread and then starts a detached task to render this CALayer into a UIImage. The whole idea is learnt from this StackOverflow post: https://stackoverflow.com/a/77834613/9202699
Here are key parts of my implementation:
class MyViewController: UIViewController {
@MainActor
func renderToUIImage(size: CGSize, itemsToDraw: [MyDrawingItem], transform: CGAffineTransform) async -> UIImage? {
// Create CALayer and add it to the view.
CATransaction.begin()
let customLayer = MyDrawingLayer()
customLayer.setupContent(itemsToDraw: itemsToDraw)
// Position the frame off-screen to it hidden.
customLayer.frame = CGRect(
origin: CGPoint(x: -100 - size.width, y: -100 - size.height),
size: size)
customLayer.masksToBounds = true
customLayer.drawsAsynchronously = true
view.layer.addSublayer(customLayer)
CATransaction.commit()
// Render CALayer to UIImage in background thread.
let image = await Task.detached {
customLayer.setNeedsDisplay()
let renderer = UIGraphicsImageRenderer(size: size)
let image = renderer.image { // CRASH happens on this line
let cgContext = $0.cgContext
cgContext.saveGState()
cgContext.concatenate(transform)
customLayer.render(in: cgContext)
cgContext.restoreGState()
}
return image
}.value
// Remove the CALayer from the view.
CATransaction.begin()
customLayer.removeFromSuperlayer()
CATransaction.commit()
return image
}
}
class MyDrawingLayer: CALayer {
var itemsToDraw: [MyDrawingItem] = []
func setupContent(itemsToDraw: [MyDrawingItem]) {
self.itemsToDraw = itemsToDraw
}
override func draw(in ctx: CGContext) {
for item in itemsToDraw {
// Render the item to the context (example pseudo-code).
// All items are thread-safe to use.
// Things to draw may include CGPath, CGImages, UIImages, NSAttributedString, etc.
item.draw(in: ctx)
}
}
}
Crash Log
The crash occurs at the following location:
Crashed: com.apple.root.default-qos.cooperative
0 MyApp 0x5cb300 closure #1 in closure #1 in MyViewController.renderToUIImage(size: CGSize, itemsToDraw: [MyDrawingItem], transform: CGAffineTransform) + 4313002752 (<compiler-generated>:4313002752)
1 MyApp 0x5cb300 closure #1 in closure #1 in MyViewController.renderToUIImage(size: CGSize, itemsToDraw: [MyDrawingItem], transform: CGAffineTransform) + 4313002752 (<compiler-generated>:4313002752)
2 MyApp 0x1a4578 AnyModifier.modified(for:) + 4308649336 (<compiler-generated>:4308649336)
3 MyApp 0x7b4e64 thunk for @escaping @callee_guaranteed (@guaranteed UIGraphicsPDFRendererContext) -> () + 4315008612 (<compiler-generated>:4315008612)
4 UIKitCore 0x1489c0 -[UIGraphicsRenderer runDrawingActions:completionActions:format:error:] + 324
5 UIKitCore 0x14884c -[UIGraphicsRenderer runDrawingActions:completionActions:error:] + 92
6 UIKitCore 0x148778 -[UIGraphicsImageRenderer imageWithActions:] + 184
7 MyApp 0x5cb1c0 closure #1 in MyViewController.renderToUIImage(size: CGSize, itemsToDraw: [MyDrawingItem], transform: CGAffineTransform) + 100 (FileName.swift:100)
8 libswift_Concurrency.dylib 0x60f5c swift::runJobInEstablishedExecutorContext(swift::Job*) + 252
9 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144
10 libdispatch.dylib 0x15ec0 _dispatch_root_queue_drain + 392
11 libdispatch.dylib 0x166c4 _dispatch_worker_thread2 + 156
12 libsystem_pthread.dylib 0x3644 _pthread_wqthread + 228
13 libsystem_pthread.dylib 0x1474 start_wqthread + 8
Questions
Is it safe to run UIGraphicsImageRenderer.image on the background thread?
Given that I want to leverage GPU rendering, what are some best practices for rendering images off the main thread while ensuring stability?
Are there alternatives to using UIGraphicsImageRenderer for background rendering that can still take advantage of GPU rendering?
It is particularly interesting that the crash logs indicate the error may be related to UIGraphicsPDFRendererContext (crash log line number 3). It would be very helpful if someone could explain the connection between starting and drawing on a UIGraphicsImageRenderer and UIGraphicsPDFRendererContext.
Any insights or guidance on this issue would be greatly appreciated. Thanks!!!
Quartz
RSS for tagAllow users to browse, edit, and save images using slideshows and Core Image filters using Quartz.
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I’m trying to create a CGContext that matches my screen using the following code
let context = CGContext(
data: pixelBuffer,
width: pixelWidth, // 3456
height: pixelHeight, // 2234
bitsPerComponent: 10, // PixelEncoding = "--RRRRRRRRRRGGGGGGGGGGBBBBBBBBBB"
bytesPerRow: bytesPerRow, // 13824
space: CGColorSpace(name: CGColorSpace.extendedSRGB)!,
bitmapInfo: CGImageAlphaInfo.none.rawValue
| CGImagePixelFormatInfo.RGBCIF10.rawValue
| CGImageByteOrderInfo.order16Little.rawValue
)
But it fails with an error
CGBitmapContextCreate: unsupported parameter combination:
RGB
10 bits/component, integer
13824 bytes/row
kCGImageAlphaNone
kCGImageByteOrder16Little
kCGImagePixelFormatRGBCIF10
Valid parameters for RGB color space model are:
16 bits per pixel, 5 bits per component, kCGImageAlphaNoneSkipFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipLast
32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedFirst
32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedLast
32 bits per pixel, 10 bits per component, kCGImageAlphaNone|kCGImagePixelFormatRGBCIF10|kCGImageByteOrder16Little
64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast
64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast
64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little
64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little
128 bits per pixel, 32 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents
128 bits per pixel, 32 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents
See Quartz 2D Programming Guide (available online) for more information.
Why is it unsupported if it matches the 6th option? (32 bits per pixel, 10 bits per component, kCGImageAlphaNone|kCGImagePixelFormatRGBCIF10|kCGImageByteOrder16Little)
I have a 3х3 Matrix which I need to apply to UIImage and save it in Documents folder. I successfully converted the 3x3 Matrix (represented as [[Double]]) to CATrasform3D and then I have broken my head with trying to figure out how to apply it to UIImage.
The only property where I can I apply it is UIView(or UIImageView in case with working with UIImage) transform property. But it has nothing to do with UIImage itself. I can't save the UIImage from transformed the UIImageView with all the transformations.
And all the CoreGraphic methods (like concatenate for CGContext) only work with affine transformations which not suits for me.
Please give me a hint what direction I should look.
Does Apple has native methods or I have to use 3rd party frameworks for this functionality?
Hi Team,
We are facing crash in CAMediaTimingCopyRenderTiming for production users. And we are unable to trace the crash.
Below is the crash stack trace -
Crashed: com.apple.main-thread
0 QuartzCore 0x14b9c CAMediaTimingCopyRenderTiming + 660
1 QuartzCore 0xfa9c -[CAAnimation _setCARenderAnimation:layer:] + 64
2 QuartzCore 0x146e4 -[CAAnimationGroup _copyRenderAnimationForLayer:] + 356
3 QuartzCore 0x12f3c CA::Layer::commit_animations(CA::Transaction*, double ()(CA::Layer, double, void*), void ()(CA::Layer, CA::Render::Animation*, void*), void ()(CA::Layer, __CFString const*, void*), CA::Render::TimingList* ()(CA::Layer, void*), void*) + 688
4 QuartzCore 0x277c invocation function for block in CA::Context::commit_transaction(CA::Transaction*, double, double*) + 176
5 QuartzCore 0x482bc CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 384
6 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
7 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
8 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
9 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
10 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
11 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
12 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
13 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
14 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
15 QuartzCore 0x48244 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 264
16 QuartzCore 0x2e078 CA::Context::commit_transaction(CA::Transaction*, double, double*) + 6224
17 QuartzCore 0x59dc0 CA::Transaction::commit() + 644
18 QuartzCore 0x44dbc CA::Transaction::flush_as_runloop_observer(bool) + 84
19 CoreFoundation 0x898e8 CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 32
20 CoreFoundation 0x1951c __CFRunLoopDoObservers + 552
21 CoreFoundation 0x75214 __CFRunLoopRun + 1004
22 CoreFoundation 0x79d20 CFRunLoopRunSpecific + 584
23 GraphicsServices 0x1998 GSEventRunModal + 160
24 UIKitCore 0x371448 -[UIApplication _run] + 868
25 UIKitCore 0x3710c0 UIApplicationMain + 312
26 SwiftUI 0x183c68 OUTLINED_FUNCTION_895 + 2184
27 SwiftUI 0xfdf1c block_copy_helper.1 + 452
28 SwiftUI 0xeaf6c OUTLINED_FUNCTION_901 + 2312
29 Evie Ring 0x2dd20c main + 10 (MovanoRingApp.swift:10)
30 ??? 0x1c7724344 (Missing)
Does anyone know why the following call fails?
CGPDFOperatorTableSetCallback(operatorTable, "ID", &callback);
The PDF specification seems to indicate that ID is an operator?
BTW what is the proper topic/subtopic for questions about Quartz? Wasn't sure what topic on the new forums to post this under.
The guide on how to make a QC composition a standalone app assumes I use an earlier version of Xcode (and retired). And Xcode, of course, has changed a lot since the past decade and the guides basically can't be used anymore.
Hi Team, some of our users are getting crash in QuartzCore. But we are not sure the exact reason for it. Can you please help us in it? App is crashing in production.
Xcode version - 15.0
Platform - iOS
Below is the crash stack trace.
Crashed: com.apple.main-thread
0 libsystem_kernel.dylib 0xa974 __pthread_kill + 8
1 libsystem_pthread.dylib 0x60ec pthread_kill + 268
2 libsystem_c.dylib 0x75b80 abort + 180
3 QuartzCore 0x98ba8 CA::Render::Encoder::grow(unsigned long) + 288
4 QuartzCore 0x97e50 CA::Render::Vector::encode(CA::Render::Encoder*) const + 112
5 QuartzCore 0x10a76c CA::Render::KeyframeAnimation::encode(CA::Render::Encoder*) const + 68
6 QuartzCore 0x975ec CA::Render::Array::encode(CA::Render::Encoder*) const + 172
7 QuartzCore 0x75204 CA::Context::commit_animation(CA::Layer*, CA::Render::Animation*, void*) + 236
8 QuartzCore 0x72998 CA::Layer::commit_animations(CA::Transaction*, double ()(CA::Layer, double, void*), void ()(CA::Layer, CA::Render::Animation*, void*), void ()(CA::Layer, __CFString const*, void*), CA::Render::TimingList* ()(CA::Layer, void*), void*) + 956
9 QuartzCore 0x2b930 invocation function for block in CA::Context::commit_transaction(CA::Transaction*, double, double*) + 148
10 QuartzCore 0x2b838 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 368
11 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
12 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
13 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
14 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
15 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
16 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
17 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
18 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
19 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
20 QuartzCore 0x2b7c4 CA::Layer::commit_if_needed(CA::Transaction*, void (CA::Layer*, unsigned int, unsigned int) block_pointer) + 252
21 QuartzCore 0x6f5b0 CA::Context::commit_transaction(CA::Transaction*, double, double*) + 11212
22 QuartzCore 0x661bc CA::Transaction::commit() + 648
23 QuartzCore 0x65e64 CA::Transaction::flush_as_runloop_observer(bool) + 88
24 CoreFoundation 0x35d3c CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 36
25 CoreFoundation 0x34738 __CFRunLoopDoObservers + 552
26 CoreFoundation 0x33e50 __CFRunLoopRun + 1028
27 CoreFoundation 0x33968 CFRunLoopRunSpecific + 608
28 GraphicsServices 0x34e0 GSEventRunModal + 164
29 UIKitCore 0x22aedc -[UIApplication _run] + 888
30 UIKitCore 0x22a518 UIApplicationMain + 340
31 SwiftUI 0x1033860 OUTLINED_FUNCTION_39 + 600
32 SwiftUI 0x10336a8 OUTLINED_FUNCTION_39 + 160
33 SwiftUI 0xc4f9fc get_witness_table 7SwiftUI4ViewRzlAA15ModifiedContentVyxAA30_EnvironmentKeyWritingModifierVySbGGAaBHPxAaBHD1__AgA0cI0HPyHCHCTm + 364
34 Evie Ring 0x324620 main + 10 (MovanoRingApp.swift:10)
35 ??? 0x1ad632d84 (Missing)