Add tap to focus and pinch to zoom for iOS

Author: guischulz

README.md

@@ -80,7 +80,7 @@ Starts the camera preview instance.
 | disableAudio | boolean | (optional) Disables audio stream to prevent permission requests, default false. (applicable to web only) |
 | lockAndroidOrientation | boolean | (optional) Locks device orientation when camera is showing, default false. (applicable to Android only) |
 | enableOpacity | boolean | (optional) Make the camera preview see-through. Ideal for augmented reality uses. Default false (applicable to Android and web only)
-| enableZoom | boolean | (optional) Set if you can pinch to zoom. Default false (applicable to Android only)
+| enableZoom | boolean | (optional) Set if you can pinch to zoom. Default false (applicable to the android and ios platforms only)
 
 <!-- <strong>Options:</strong>
 All options stated are optional and will default to values here

ios/Plugin/CameraController.swift

@@ -34,6 +34,8 @@ class CameraController: NSObject {
 
     var audioDevice: AVCaptureDevice?
     var audioInput: AVCaptureDeviceInput?
+    
+    var zoomFactor: CGFloat = 1.0
 }
 
 extension CameraController {
@@ -162,6 +164,25 @@ extension CameraController {
         self.previewLayer?.frame = view.frame
     }
 
+    func setupGestures(target: UIView, enableZoom: Bool) {
+        setupTapGesture(target: target, selector: #selector(handleTap(_:)), delegate: self)
+        if (enableZoom) {
+            setupPinchGesture(target: target, selector: #selector(handlePinch(_:)), delegate: self)
+        }
+    }
+    
+    func setupTapGesture(target: UIView, selector: Selector, delegate: UIGestureRecognizerDelegate?) {
+        let tapGesture = UITapGestureRecognizer(target: self, action: selector)
+        tapGesture.delegate = delegate
+        target.addGestureRecognizer(tapGesture)
+    }
+    
+    func setupPinchGesture(target: UIView, selector: Selector, delegate: UIGestureRecognizerDelegate?) {
+        let pinchGesture = UIPinchGestureRecognizer(target: self, action: selector)
+        pinchGesture.delegate = delegate
+        target.addGestureRecognizer(pinchGesture)
+    }
+
     func updateVideoOrientation() {
         assert(Thread.isMainThread) // UIApplication.statusBarOrientation requires the main thread.
 
@@ -416,6 +437,67 @@ extension CameraController {
     }
 }
 
+extension CameraController: UIGestureRecognizerDelegate {
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        return true;
+    }
+    
+    @objc
+    func handleTap(_ tap: UITapGestureRecognizer) {
+        guard let device = self.currentCameraPosition == .rear ? rearCamera : frontCamera else { return }
+        
+        let point = tap.location(in: tap.view)
+        let devicePoint = self.previewLayer?.captureDevicePointConverted(fromLayerPoint: point)
+        
+        do {
+            try device.lockForConfiguration()
+            defer { device.unlockForConfiguration() }
+            
+            let focusMode = AVCaptureDevice.FocusMode.autoFocus
+            if device.isFocusPointOfInterestSupported && device.isFocusModeSupported(focusMode) {
+                device.focusPointOfInterest = CGPoint(x: CGFloat(devicePoint?.x ?? 0), y: CGFloat(devicePoint?.y ?? 0))
+                device.focusMode = focusMode
+            }
+            
+            let exposureMode = AVCaptureDevice.ExposureMode.autoExpose
+            if device.isExposurePointOfInterestSupported && device.isExposureModeSupported(exposureMode) {
+                device.exposurePointOfInterest = CGPoint(x: CGFloat(devicePoint?.x ?? 0), y: CGFloat(devicePoint?.y ?? 0))
+                device.exposureMode = exposureMode
+            }
+        } catch {
+            debugPrint(error)
+        }
+    }
+    
+    @objc
+    private func handlePinch(_ pinch: UIPinchGestureRecognizer) {
+        guard let device = self.currentCameraPosition == .rear ? rearCamera : frontCamera else { return }
+        
+        func minMaxZoom(_ factor: CGFloat) -> CGFloat { return max(1.0, min(factor, device.activeFormat.videoMaxZoomFactor)) }
+        
+        func update(scale factor: CGFloat) {
+            do {
+                try device.lockForConfiguration()
+                defer { device.unlockForConfiguration() }
+                
+                device.videoZoomFactor = factor
+            } catch {
+                debugPrint(error)
+            }
+        }
+        
+        switch pinch.state {
+        case .began: fallthrough
+        case .changed:
+            let newScaleFactor = minMaxZoom(pinch.scale * zoomFactor)
+            update(scale: newScaleFactor)
+        case .ended:
+            zoomFactor = device.videoZoomFactor
+        default: break
+        }
+    }
+}
+
 extension CameraController: AVCapturePhotoCaptureDelegate {
     public func photoOutput(_ captureOutput: AVCapturePhotoOutput, didFinishProcessingPhoto photoSampleBuffer: CMSampleBuffer?, previewPhoto previewPhotoSampleBuffer: CMSampleBuffer?,
                             resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Swift.Error?) {

ios/Plugin/Plugin.swift

@@ -19,6 +19,7 @@ public class CameraPreview: CAPPlugin {
     var rotateWhenOrientationChanged: Bool?
     var toBack: Bool?
     var storeToFile: Bool?
+    var enableZoom: Bool?
     var highResolutionOutput: Bool = false
 
     @objc func rotated() {
@@ -78,6 +79,7 @@ public class CameraPreview: CAPPlugin {
         self.rotateWhenOrientationChanged = call.getBool("rotateWhenOrientationChanged") ?? true
         self.toBack = call.getBool("toBack") ?? false
         self.storeToFile = call.getBool("storeToFile") ?? false
+        self.enableZoom = call.getBool("enableZoom") ?? false
 
         AVCaptureDevice.requestAccess(for: .video, completionHandler: { (granted: Bool) in
             guard granted else {
@@ -106,6 +108,9 @@ public class CameraPreview: CAPPlugin {
                         }
                         try? self.cameraController.displayPreview(on: self.previewView)
 
+                        let frontView = self.toBack! ? self.webView : self.previewView;
+                        self.cameraController.setupGestures(target: frontView ?? self.previewView, enableZoom: self.enableZoom!)
+                        
                         if (self.rotateWhenOrientationChanged == true) {
                             NotificationCenter.default.addObserver(self, selector: #selector(CameraPreview.rotated), name: UIDevice.orientationDidChangeNotification, object: nil)
                         }