feat: Add takeSnapshot() to PreviewView

package/ios/Core/CameraError.swift

@@ -179,6 +179,7 @@ enum CaptureError {
   case createRecorderError(message: String? = nil)
   case videoNotEnabled
   case photoNotEnabled
+  case snapshotFailed
   case aborted
   case insufficientStorage
   case unknown(message: String? = nil)
@@ -197,6 +198,8 @@ enum CaptureError {
       return "create-recorder-error"
     case .videoNotEnabled:
       return "video-not-enabled"
+    case .snapshotFailed:
+      return "snapshot-failed"
     case .photoNotEnabled:
       return "photo-not-enabled"
     case .insufficientStorage:
@@ -222,6 +225,8 @@ enum CaptureError {
       return "Failed to create the AVAssetWriter (Recorder)! \(message ?? "(no additional message)")"
     case .videoNotEnabled:
       return "Video capture is disabled! Pass `video={true}` to enable video recordings."
+    case .snapshotFailed:
+      return "Failed to take a Snapshot of the Preview View! Try using takePhoto() instead."
     case .photoNotEnabled:
       return "Photo capture is disabled! Pass `photo={true}` to enable photo capture."
     case .aborted:

package/ios/Core/PreviewView.swift

@@ -46,6 +46,23 @@ class PreviewView: UIView {
     return videoPreviewLayer.captureDevicePointConverted(fromLayerPoint: point)
   }
 
+  func takeSnapshot() throws -> UIImage {
+    UIGraphicsBeginImageContextWithOptions(videoPreviewLayer.frame.size, false, 0)
+    defer {
+      UIGraphicsEndImageContext()
+    }
+    guard let context = UIGraphicsGetCurrentContext() else {
+      throw CameraError.capture(.snapshotFailed)
+    }
+
+    videoPreviewLayer.render(in: context)
+
+    guard let image = UIGraphicsGetImageFromCurrentImageContext() else {
+      throw CameraError.capture(.snapshotFailed)
+    }
+    return image
+  }
+
   init(frame: CGRect, session: AVCaptureSession) {
     super.init(frame: frame)
     videoPreviewLayer.session = session