Merge pull request hyperoslo#331 from weslindsay/add-zoom-gesture

Add pinch to zoom

Source/CameraView/CameraMan.swift

@@ -204,6 +204,16 @@ class CameraMan {
     }
   }
 
+  func zoom(_ zoomFactor: CGFloat) {
+    guard let device = currentInput?.device, device.position == .back else { return }
+
+    queue.async {
+      self.lock {
+        device.videoZoomFactor = zoomFactor
+      }
+    }
+  }
+
   // MARK: - Lock
 
   func lock(_ block: () -> Void) {

Source/CameraView/CameraView.swift

@@ -81,6 +81,13 @@ class CameraView: UIViewController, CLLocationManagerDelegate, CameraManDelegate
     return gesture
     }()
 
+  lazy var pinchGestureRecognizer: UIPinchGestureRecognizer = { [unowned self] in
+    let gesture = UIPinchGestureRecognizer()
+    gesture.addTarget(self, action: #selector(pinchGestureRecognizerHandler(_:)))
+
+    return gesture
+    }()
+
   let cameraMan = CameraMan()
 
   var previewLayer: AVCaptureVideoPreviewLayer?
@@ -89,6 +96,12 @@ class CameraView: UIViewController, CLLocationManagerDelegate, CameraManDelegate
   var locationManager: LocationManager?
   var startOnFrontCamera: Bool = false
 
+  private let minimumZoomFactor: CGFloat = 1.0
+  private let maximumZoomFactor: CGFloat = 3.0
+
+  private var currentZoomFactor: CGFloat = 1.0
+  private var previousZoomFactor: CGFloat = 1.0
+
   public init(configuration: Configuration? = nil) {
     if let configuration = configuration {
       self.configuration = configuration
@@ -118,6 +131,10 @@ class CameraView: UIViewController, CLLocationManagerDelegate, CameraManDelegate
 
     view.addGestureRecognizer(tapGestureRecognizer)
 
+    if configuration.allowPinchToZoom {
+      view.addGestureRecognizer(pinchGestureRecognizer)
+    }
+
     cameraMan.delegate = self
     cameraMan.setup(self.startOnFrontCamera)
   }
@@ -244,6 +261,16 @@ class CameraView: UIViewController, CLLocationManagerDelegate, CameraManDelegate
     })
   }
 
+  func zoomTo(_ zoomFactor: CGFloat) {
+    guard let device = cameraMan.currentInput?.device else { return }
+
+    let maximumDeviceZoomFactor = device.activeFormat.videoMaxZoomFactor
+    let newZoomFactor = previousZoomFactor * zoomFactor
+    currentZoomFactor = min(maximumZoomFactor, max(minimumZoomFactor, min(newZoomFactor, maximumDeviceZoomFactor)))
+
+    cameraMan.zoom(currentZoomFactor)
+  }
+
   // MARK: - Tap
 
   func tapGestureRecognizerHandler(_ gesture: UITapGestureRecognizer) {
@@ -254,6 +281,21 @@ class CameraView: UIViewController, CLLocationManagerDelegate, CameraManDelegate
     focusTo(touch)
   }
 
+  // MARK: - Pinch
+
+  func pinchGestureRecognizerHandler(_ gesture: UIPinchGestureRecognizer) {
+    switch gesture.state {
+    case .began:
+      fallthrough
+    case .changed:
+      zoomTo(gesture.scale)
+    case .ended:
+      zoomTo(gesture.scale)
+      previousZoomFactor = currentZoomFactor
+    default: break
+    }
+  }
+
   // MARK: - Private helpers
 
   func showNoCamera(_ show: Bool) {

Source/Configuration.swift

@@ -48,6 +48,7 @@ public struct Configuration {
   public var showsImageCountLabel = true
   public var flashButtonAlwaysHidden = false
   public var managesAudioSession = true
+  public var allowPinchToZoom = true
 
   // MARK: Images
   public var indicatorView: UIView = {