DragonflAI SDK for iOS

Usage

Initialising

DragonflAI is a commercial product and requires licensing details during framework initialization. This should have been provided alongside this documentation, but if not please contact support@dragonflai.co.

Initialise early in your app’s startup. For example here in the AppDelegate method application:willFinishLaunchingWithOptions:, we call useAccount() with our license details.

class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        
        // To see debug log messages, pass a debug logger.
        // NB: limit use to debug builds 
        DragonflAICore.useLogger(logger: ConsoleLogger(logLevel: .debug))
        
        let account = Account(key: "your_key", secret: "your_secret")        
        DragonflAICore.useAccount(account)
        
        return true
    }
}

This is a basic example. You may wish to keep your credentials in config rather than code.

Moderating an image

Create a Moderator instance, and pass an image to moderate().

Basic example using a closure to handle the result:

let image: UIImage = [your choice of image]

Moderator(algorithm: .nudity1).moderate(image) { (moderationResult) in
            
    // *** update model in background thread ***

    // *** example of expanding result ***
    switch moderationResult {
    case .success(let success):
        switch success.analysis.decision {
        case .ok:
            // moderator allowed this image
        case .blocked:
            // moderator blocked this image
        @unknown default:
            // this covers any future return types 
        }
    case .failure(let error):
        // moderation error
    }
    
    DispatchQueue.main.async {
        // *** update UI in main thread ***
    }
}

⚠️ You should assume the closure is not called on the main queue, and dispatch UI updates accordingly.

Configuring a moderator

You may want to configure and reuse a Moderator instance instead of creating it every time.

It can take an optional AlgorithmConfig object if you don’t want to use the defaults.

let config = AlgorithmConfig(blockThreshold: 50)
let moderator = Moderator(algorithm: .nudity1, config: config)

// ...

moderator.moderate(image) { (moderationResult) in 
    // use result
}

Promises (PromiseKit)

You can also get the results via PromiseKit promises.

moderator?.moderate(image)
    .map { (success: ModeratorSuccess) in
        // use analysis and metadata
    }
    .catch { error in
        // handle error
    }

Moderating a video stream

Streams of images can also be moderated in v1.4+. Typically these come from the device cameras and are passed to a codec for streaming or real-time communication.

Creating a StreamModerator

Get a StreamModerator by asking a Moderator to createStreamModerator()

class MyClass {
    private var streamModerator: StreamModerator?

    init() {
        let moderator = Moderator(algorithm: .nudity1)
        streamModerator = moderator.createStreamModerator()
        streamModerator?.delegate = self    
    }
}

Supplying stream frames

Pass the frames, e.g. from the camera, to the process(frame:) method.

extension MyClass: AVCaptureVideoDataOutputSampleBufferDelegate {    
  func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

    let pixelBuffer: CVPixelBuffer? = CMSampleBufferGetImageBuffer(sampleBuffer)

    guard let pixelBuffer = pixelBuffer else {
      return
    }

    streamModerator?.process(frame: pixelBuffer)

    // pass pixelBuffer to codec (dependent on moderation result) 
  }

}

Getting results

To get results, assign a delegate, typically the same class.

extension MyClass: StreamModeratorDelegate {
    func moderatorDidProduceNewResult(_ moderator: StreamModerator,
                                      result moderationResult: ModeratorResult) {
        
        guard moderator == self.streamModerator else {
            return
        }

        // use moderationResult
    }

    func moderatorDidDropFrame(_ moderator: StreamModerator) {
        // dropped frame
    }
}

Getting stream statistics

The StreamModerator can provide statistics on the number of frames it is receiving and processing.

func printStats() {
    print("Input FPS: \(streamModerator.inputFramesPerSecond) / Processed FPS: \(moderator.processedFramesPerSecond)")
}

For consistent results, reset those stats when starting or resuming a session, so periods with no frames are not included.

func startVideoSession() {
    // ...

    streamModerator?.resetFPSStats()

    // ...
}