Add a protocol for scanning extensibility

CardScan/Classes/Ocr.swift

@@ -5,6 +5,7 @@ public class Ocr {
     public var expiry: Expiry?
 
     public var errorCorrectionDuration = 1.0
+    var scanEventsDelegate: ScanEvents?
 
     public init() {}
 
@@ -91,6 +92,15 @@ public class Ocr {
         }
 
         if let number = number {
+            // Note: the onScanComplete method is called in ScanBaseViewController
+            let xmin = findFour.predictedBoxes.map { $0.minX }.min() ?? 0.0
+            let xmax = findFour.predictedBoxes.map { $0.maxX }.max() ?? 0.0
+            let ymin = findFour.predictedBoxes.map { $0.minY }.min() ?? 0.0
+            let ymax = findFour.predictedBoxes.map { $0.maxY }.max() ?? 0.0
+            let numberBoundingBox = CGRect(x: xmin, y: ymin, width: (xmax - xmin), height: (ymax - ymin))
+            self.scanEventsDelegate?.onNumberRecognized(number: number, expiry:
+                findFour.expiry, cardImage: rawImage, numberBoundingBox: numberBoundingBox, expiryBoundingBox: findFour.expiryBoxes.first)
+
             self.scanStats.algorithm = findFour.algorithm
             self.updateStats(model: findFour.modelString, boxes: findFour.predictedBoxes, image: rawImage, number: number, cvvBoxes: findFour.cvvBoxes)
             return number

CardScan/Classes/ScanBaseViewController.swift

@@ -15,6 +15,8 @@ import Vision
     @objc public var includeCardImage = false
     @objc public var showDebugImageView = false
 
+    public var scanEventsDelegate: ScanEvents?
+
     static public let machineLearningQueue = DispatchQueue(label: "CardScanMlQueue")
     // Only access this variable from the machineLearningQueue
     static var hasRegisteredAppNotifications = false
@@ -41,7 +43,7 @@ import Vision
     @objc open func onScannedCard(number: String, expiryYear: String?, expiryMonth: String?, scannedImage: UIImage?) { }
     @objc open func showCardNumber(_ number: String, expiry: String?) { }
 
-    func toggleTorch() {
+    public func toggleTorch() {
         self.ocr.scanStats.torchOn = !self.ocr.scanStats.torchOn
         self.videoFeed.toggleTorch()
     }
@@ -178,6 +180,10 @@ import Vision
         self.videoFeed.setup(captureDelegate: self, completion: { success in })
 
         self.ocr.errorCorrectionDuration = self.errorCorrectionDuration
+
+        // we split the implementation between OCR, which calls `onNumberRecognized`
+        // and ScanBaseViewController, which calls `onScanComplete`
+        self.ocr.scanEventsDelegate = self.scanEventsDelegate
         self.previewView?.videoPreviewLayer.session = self.videoFeed.session
 
         self.videoFeed.pauseSession()
@@ -354,8 +360,9 @@ import Vision
                 if self.calledOnScannedCard {
                     return
                 }
-
                 self.calledOnScannedCard = true
+                // Note: the onNumberRecognized method is called on Ocr
+                self.scanEventsDelegate?.onScanComplete()
 
                 let expiryMonth = expiry.map { String($0.month) }
                 let expiryYear = expiry.map { String($0.year) }

CardScan/Classes/ScanEventsProtocol.swift

@@ -0,0 +1,13 @@
+//
+//  ScanEventsProtocol.swift
+//  CardScan
+//
+//  Created by Sam King on 8/9/19.
+//
+
+import Foundation
+
+public protocol ScanEvents {
+    func onNumberRecognized(number: String, expiry: Expiry?, cardImage: CGImage, numberBoundingBox: CGRect, expiryBoundingBox: CGRect?)
+    func onScanComplete()
+}

Example/CardScan/ViewController.swift

@@ -9,8 +9,8 @@
 import UIKit
 import CardScan
 
-class ViewController: UIViewController, ScanDelegate, ScanStringsDataSource, TestingImageDataSource {
-    
+class ViewController: UIViewController, ScanEvents, ScanDelegate, ScanStringsDataSource, TestingImageDataSource {
+
     let testImages = [UIImage(imageLiteralResourceName: "frame0"),
                       UIImage(imageLiteralResourceName: "frame19"),
                       UIImage(imageLiteralResourceName: "frame38"),
@@ -162,12 +162,22 @@ class ViewController: UIViewController, ScanDelegate, ScanStringsDataSource, Tes
         self.present(vc, animated: true)
     }
 
+    func onNumberRecognized(number: String, expiry: Expiry?, cardImage: CGImage, numberBoundingBox: CGRect, expiryBoundingBox: CGRect?) {
+        print("number recognized")
+    }
+
+    func onScanComplete() {
+        print("scan complete")
+    }
+
     @IBAction func scanWithStatsPress() {
         ScanViewController.configure(apiKey: "0xdeadbeef")
         guard let vc = ScanViewController.createViewController(withDelegate: self) else {
             print("scan view controller not supported on this hardware")
             return
         }
+        vc.scanEventsDelegate = self
+
         self.present(vc, animated: true)
     }
 }