Ensure custom exposure mode is supported

Reviewed-on: #6
Reviewed-by: Ivan Malison <ivanmalison@gmail.com>

package/ios/CameraView+RecordVideo.swift

@@ -50,4 +50,12 @@ extension CameraView: AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureAud
   func resumeRecording(promise: Promise) {
     cameraSession.resumeRecording(promise: promise)
   }
+  
+  func lockExposure(promise: Promise) {
+    cameraSession.lockCurrentExposure(promise: promise)
+  }
+  
+  func unlockExposure(promise: Promise) {
+    cameraSession.unlockCurrentExposure(promise: promise)
+  }
 }

package/ios/CameraView.swift

@@ -87,7 +87,6 @@ public final class CameraView: UIView, CameraSessionDelegate {
   var pinchGestureRecognizer: UIPinchGestureRecognizer?
   var pinchScaleOffset: CGFloat = 1.0
   private var currentConfigureCall: DispatchTime?
-  var lastProcessedTime: Date?
 
   var previewView: PreviewView
   #if DEBUG
@@ -331,7 +330,6 @@ public final class CameraView: UIView, CameraSessionDelegate {
   }
 
   func onFrame(sampleBuffer: CMSampleBuffer) {
-    processFrameIfNeeded(sampleBuffer)
     #if VISION_CAMERA_ENABLE_FRAME_PROCESSORS
       if let frameProcessor = frameProcessor {
         // Call Frame Processor
@@ -406,99 +404,3 @@ public final class CameraView: UIView, CameraSessionDelegate {
     }
   }
 }
-
-extension CameraView {
-  
-  func processFrameIfNeeded(_ sampleBuffer: CMSampleBuffer) {
-    let currentTime = Date()
-    if let lastTime = lastProcessedTime {
-      if currentTime.timeIntervalSince(lastTime) >= 10.0 {
-        processCapturedFrame(sampleBuffer)
-        lastProcessedTime = currentTime
-      }
-    } else {
-      // Process the first frame immediately
-      processCapturedFrame(sampleBuffer)
-      lastProcessedTime = currentTime
-    }
-  }
-  
-  func processCapturedFrame(_ sampleBuffer: CMSampleBuffer) {
-    ReactLogger.log(level: .info, message: "processCapturedFrame")
-    // Your existing processing logic
-    guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return }
-    
-    let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
-    
-    // Analyze for white balance
-    let isWhiteBalanceIssue = analyzeFrameForWhiteBalance(ciImage: ciImage)
-    
-    if isWhiteBalanceIssue {
-      ReactLogger.log(level: .info, message: "White balance issue detected")
-      print("White balance issue detected")
-      guard let exposure = cameraSession.configuration?.exposure else {
-        updateExposure(0.5)
-        return
-      }
-      updateExposure(exposure - 0.2)
-      ReactLogger.log(level: .info, message: "Exposure = \(exposure)")
-    } else {
-      ReactLogger.log(level: .info, message: "White balance is okay")
-      print("White balance is okay. Exposure = \(cameraSession.configuration?.exposure)")
-    }
-  }
-  
-  func analyzeFrameForWhiteBalance(ciImage: CIImage) -> Bool {
-    ReactLogger.log(level: .info, message: "analyzeFrameForWhiteBalance")
-    let extent = ciImage.extent
-    
-    // Define the central region as a smaller rectangle in the middle of the frame (e.g., 1/4 the size)
-    let centerRect = CGRect(
-      x: extent.origin.x + extent.size.width * 0.25,
-      y: extent.origin.y + extent.size.height * 0.25,
-      width: extent.size.width * 0.5,
-      height: extent.size.height * 0.5
-    )
-    
-    // Crop the image to the centerRect
-    let croppedImage = ciImage.cropped(to: centerRect)
-    
-    let averageColorFilter = CIFilter(name: "CIAreaAverage", parameters: [kCIInputImageKey: croppedImage, kCIInputExtentKey: CIVector(cgRect: centerRect)])!
-    
-    guard let outputImage = averageColorFilter.outputImage else {
-      ReactLogger.log(level: .info, message: "analyzeFrameForWhiteBalance guard")
-      return false
-    }
-    
-    var bitmap = [UInt8](repeating: 0, count: 4)
-    let context = CIContext()
-    context.render(outputImage, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: .RGBA8, colorSpace: nil)
-    
-    let red = Float(bitmap[0]) / 255.0
-    let green = Float(bitmap[1]) / 255.0
-    let blue = Float(bitmap[2]) / 255.0
-    
-    ReactLogger.log(level: .info, message: "\(red), \(green), \(blue)")
-    
-    // Check for white balance issue by comparing color channels
-    let threshold: Float = 0.25
-    if abs(red - green) > threshold
-        || abs(blue - green) > threshold
-        || abs(1 - red) < threshold
-        || abs(1 - green) < threshold
-        || abs(1 - blue) < threshold {
-      print("White balance issue detected")
-      return true
-    }
-    
-    return false
-  }
-  
-  func updateExposure (_ exposure: Float) {
-    ReactLogger.log(level: .info, message: "Updating exposure: [\(exposure)]")
-    
-    cameraSession.configure { config in
-      config.exposure = exposure
-    }
-  }
-}

package/ios/CameraViewManager.m

@@ -86,5 +86,13 @@ RCT_EXTERN_METHOD(focus
                   : (NSDictionary*)point resolve
                   : (RCTPromiseResolveBlock)resolve reject
                   : (RCTPromiseRejectBlock)reject);
+RCT_EXTERN_METHOD(lockCurrentExposure
+                  : (nonnull NSNumber*)node resolve
+                  : (RCTPromiseResolveBlock)resolve reject
+                  : (RCTPromiseRejectBlock)reject);
+RCT_EXTERN_METHOD(unlockCurrentExposure
+                  : (nonnull NSNumber*)node resolve
+                  : (RCTPromiseResolveBlock)resolve reject
+                  : (RCTPromiseRejectBlock)reject);
 
 @end

package/ios/CameraViewManager.swift

@@ -111,6 +111,18 @@ final class CameraViewManager: RCTViewManager {
     }
   }
   
+  @objc
+  final func lockCurrentExposure(_ node: NSNumber, resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
+    let component = getCameraView(withTag: node)
+    component.lockExposure(promise: Promise(resolver: resolve, rejecter: reject))
+  }
+  
+  @objc
+  final func unlockCurrentExposure(_ node: NSNumber, resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
+    let component = getCameraView(withTag: node)
+    component.unlockExposure(promise: Promise(resolver: resolve, rejecter: reject))
+  }
+
   // MARK: Private
 
   private func getCameraView(withTag tag: NSNumber) -> CameraView {

package/ios/Core/CameraSession+Video.swift

@@ -191,4 +191,68 @@ extension CameraSession {
       }
     }
   }
+
+  func lockCurrentExposure(promise: Promise) {
+    CameraQueues.cameraQueue.async {
+      withPromise(promise) {
+        guard let captureDevice = AVCaptureDevice.default(for: .video) else {
+          print("No capture device available")
+          return
+        }
+
+        guard captureDevice.isExposureModeSupported(.custom) else {
+          ReactLogger.log(level: .info, message: "Custom exposure mode not supported")
+          return
+        }
+        do {
+          // Lock the device for configuration
+          try captureDevice.lockForConfiguration()
+
+          // Get the current exposure duration and ISO
+          let currentExposureDuration = captureDevice.exposureDuration
+          let currentISO = captureDevice.iso
+
+          // Check if the device supports custom exposure settings
+          if captureDevice.isExposureModeSupported(.custom) {
+            // Lock the current exposure and ISO by setting custom exposure mode
+            captureDevice.setExposureModeCustom(duration: currentExposureDuration, iso: currentISO, completionHandler: nil)
+            ReactLogger.log(level: .info, message: "Exposure and ISO locked at current values")
+          } else {
+            ReactLogger.log(level: .info, message:"Custom exposure mode not supported")
+          }
+
+          // Unlock the device after configuration
+          captureDevice.unlockForConfiguration()
+
+        } catch {
+          ReactLogger.log(level: .warning, message:"Error locking exposure: \(error)")
+        }
+
+        return nil
+      }
+    }
+  }
+
+  func unlockCurrentExposure(promise: Promise) {
+    CameraQueues.cameraQueue.async {
+      withPromise(promise) {
+        guard let captureDevice = AVCaptureDevice.default(for: .video) else {
+          print("No capture device available")
+          return
+        }
+
+        do {
+          if captureDevice.isExposureModeSupported(.autoExpose) {
+            try captureDevice.lockForConfiguration()
+            captureDevice.exposureMode = .continuousAutoExposure
+            captureDevice.unlockForConfiguration()
+          }
+        } catch {
+          ReactLogger.log(level: .warning, message:"Error unlocking exposure: \(error)")
+        }
+
+        return nil
+      }
+    }
+  }
 }

package/src/Camera.tsx

@@ -319,6 +319,22 @@ export class Camera extends React.PureComponent<CameraProps, CameraState> {
       throw tryParseNativeCameraError(e)
     }
   }
+
+  public async lockCurrentExposure(): Promise<void> {
+    try {
+      return await CameraModule.lockCurrentExposure(this.handle)
+    } catch (e) {
+      throw tryParseNativeCameraError(e)
+    }
+  }
+
+  public async unlockCurrentExposure(): Promise<void> {
+    try {
+      return await CameraModule.unlockCurrentExposure(this.handle)
+    } catch (e) {
+      throw tryParseNativeCameraError(e)
+    }
+  }
   //#endregion
 
   //#region Static Functions (NativeModule)