CIContext createCGImage memory leak?

Question

I am encountering a memory leak. According to the Profiler (with allocations), it happens in the createCGImage function of CIContext. I've been looking and finding similar issues here on stackoverflow, but I havent found a solution yet. I tried to wrap it in an autoreleasepool, but I still have the memory leak.

How is one meant to create a CGImage from CIContext without leaking memory in swift4?

func session(_ session: ARSession, didUpdate frame: ARFrame) {
    // Only run when currentFrame is finished
    guard self.currentPixelBuffer == nil else { return } // , case .normal = frame.camera.trackingState
    self.currentPixelBuffer = frame.capturedImage

    guard let currentPixelBuffer = self.currentPixelBuffer else {return }

    let ciImage = CIImage(cvPixelBuffer: currentPixelBuffer).oriented(CGImagePropertyOrientation.init(UIDevice.current.orientation))

    let cgImage: CGImage? = self.context?.createCGImage(ciImage, from: ciImage.extent)
    // var cgImage: CGImage?
    // autoreleasepool { [weak self] () -> () in
    //     cgImage = self?.context?.createCGImage(ciImage, from: ciImage.extent)
    // }

    guard let unwrappedCgImage = cgImage else { return }
    let uiImage = UIImage.init(cgImage: unwrappedCgImage)

    let visionImage = VisionImage(image: uiImage)

    self.backgroundQueue.async {
        self.textDetector?.detect(in: visionImage, completion: { [weak self] (features, error) in
        ...

P.s. here is my context declaration:

var context: CIContext? = CIContext.init(options: nil)

score 1 · Accepted Answer · answered Jun 28 '18 at 06:58

So, the problem was actually in the "self.textDetector?.detect(in: visionImage ..." call. It kept a strong reference to the visionImage.

I wasn't able to fix that, but I was able to work around the issue by letting VisionImage take the rotation into account instead of rotating the image myself....

I ended up with this working code:

func session(_ session: ARSession, didUpdate frame: ARFrame) {
    // Only run when currentFrame is finished
    guard self.currentPixelBuffer == nil else { return } // , case .normal = frame.camera.trackingState
    self.currentPixelBuffer = frame.capturedImage

    guard let currentPixelBuffer = self.currentPixelBuffer else { return }
    let visionImage = VisionImage(buffer: self.getCMSampleBuffer(pixelBuffer: currentPixelBuffer))

    let metadata = VisionImageMetadata()
    switch UIApplication.shared.statusBarOrientation {
    case .landscapeLeft:
        metadata.orientation = .bottomRight
    case .landscapeRight:
        metadata.orientation = .topLeft
    case .portrait:
        metadata.orientation = .rightTop
    case .portraitUpsideDown:
        metadata.orientation = .leftBottom
    default:
        metadata.orientation = .topLeft
    }

    visionImage.metadata = metadata

    self.backgroundQueue.async {
        self.textDetector?.detect(in: visionImage, completion: { [weak self] (features, error) in

CIContext createCGImage memory leak?

1 Answers1