In Apple's documentation it says this:"This method, though convenient, is inefficient if used multiple times in succession. Achieve better performance by chaining filters without asking for the outputs of individual filters."That confuses me though because I don't know how to link them together without getting the output. For example, this is my method to apply a TiltShift filter, based on the instructions from Apple's docs. When I perform the gradient filter, I have to take the outputImage of that to pass into the next filter. What's the right way to be doing this? override public var outputImage: CIImage? { guard let inputImage = inputImage else { return nil } let clamped = inputImage.clampedToExtent() let blurredImage = clamped.applyingGaussianBlur(sigma: inputRadius) var gradientParameters = [ "inputPoint0": CIVector(x: 0, y: 0.75 * inputImage.extent.height), "inputColor0": CIColor(red: 0, green: 1, blue: 0, alpha: 1), "inputPoint1": CIVector(x: 0, y: 0.5 * inputImage.extent.height), "inputColor1": CIColor(red: 0, green: 1, blue: 0, alpha: 0) ]; guard let gradientImage = ciImage(from: "CILinearGradient", parameters: gradientParameters) else { return nil } gradientParameters["inputPoint0"] = CIVector(x: 0, y: 0.25 * inputImage.extent.height) guard let backgroundGradientImage = ciImage(from: "CILinearGradient", parameters: gradientParameters) else { return nil } let maskParameters = [ kCIInputImageKey: gradientImage, kCIInputBackgroundImageKey: backgroundGradientImage ] guard let maskImage = ciImage(from: "CIAdditionCompositing", parameters: maskParameters) else { return nil } let combinedParameters = [ kCIInputImageKey: blurredImage, kCIInputBackgroundImageKey: clamped, kCIInputMaskImageKey: maskImage ] return ciImage(from: "CIBlendWithMask", parameters: combinedParameters) } private func ciImage(from filterName: String, parameters: [String: Any]) -> CIImage? { guard let filtered = CIFilter(name: filterName, parameters: parameters) else { return nil } return filtered.outputImage }

I'm trying to wrap my head around Combine still, and so in my class that handles web requests I've written this method:static func downloadNumbersPublisher(datesByType: [LottoType: (start: Date, end: Date)]) -> URLSession.DataTaskPublisher { guard let url = downloadUrl(using: datesByType) else { return } var request = URLRequest(url: url) request.addValue("gzip", forHTTPHeaderField: "Accept-Encoding") let session = URLSession(configuration: .ephemeral) return session.dataTaskPublisher(for: request) }What I'm not clear on though is what I actually return on line 2, the guard statement.

How do I get errors from the simulator when something is wrong with the pkpass file? I have a 'good' version of my pass.json that drags into the simulator without issues. I have a different version that does nothing, so clearly something is wrong with the JSON, but I can't find what.In the simulator I've done Debug -> Open System Log but when I drag in the bad pkpass file, nothing is displayed.