feat(ios): customize white balance

added possibility to customize white balance settings (temperature, tint, rgb gains offset)

ios/RN/RNCamera.h

@@ -35,6 +35,7 @@
 @property(copy, nonatomic) NSDictionary *autoFocusPointOfInterest;
 @property(assign, nonatomic) float focusDepth;
 @property(assign, nonatomic) NSInteger whiteBalance;
+@property(copy, nonatomic) NSDictionary *customWhiteBalance;
 @property(assign, nonatomic) float exposure;
 @property(assign, nonatomic) float exposureIsoMin;
 @property(assign, nonatomic) float exposureIsoMax;

ios/RN/RNCamera.m

@@ -616,11 +616,30 @@ BOOL _sessionInterrupted = NO;
         [device setWhiteBalanceMode:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance];
         [device unlockForConfiguration];
     } else {
-        AVCaptureWhiteBalanceTemperatureAndTintValues temperatureAndTint = {
-            .temperature = [RNCameraUtils temperatureForWhiteBalance:self.whiteBalance],
-            .tint = 0,
-        };
-        AVCaptureWhiteBalanceGains rgbGains = [device deviceWhiteBalanceGainsForTemperatureAndTintValues:temperatureAndTint];
+        AVCaptureWhiteBalanceGains rgbGains;
+        if (self.whiteBalance == RNCameraWhiteBalanceCustom
+            && [self.customWhiteBalance objectForKey:@"temperature"]
+            && [self.customWhiteBalance objectForKey:@"tint"]) {
+            
+            float temperature = [self.customWhiteBalance[@"temperature"] floatValue];
+            float tint = [self.customWhiteBalance[@"tint"] floatValue];
+            
+            AVCaptureWhiteBalanceTemperatureAndTintValues temperatureAndTint = {
+                .temperature = temperature,
+                .tint = tint,
+            };
+            rgbGains = [device deviceWhiteBalanceGainsForTemperatureAndTintValues:temperatureAndTint];
+            rgbGains.redGain += [self.customWhiteBalance[@"redGainOffset"] floatValue];
+            rgbGains.greenGain += [self.customWhiteBalance[@"greenGainOffset"] floatValue];
+            rgbGains.blueGain += [self.customWhiteBalance[@"blueGainOffset"] floatValue];
+        } else {
+            AVCaptureWhiteBalanceTemperatureAndTintValues temperatureAndTint = {
+                .temperature = [RNCameraUtils temperatureForWhiteBalance:self.whiteBalance],
+                .tint = 0,
+            };
+            rgbGains = [device deviceWhiteBalanceGainsForTemperatureAndTintValues:temperatureAndTint];
+        }
+        
         __weak __typeof__(device) weakDevice = device;
         if ([device lockForConfiguration:&error]) {
             @try{

ios/RN/RNCameraManager.h

@@ -32,6 +32,7 @@ typedef NS_ENUM(NSInteger, RNCameraAutoFocus) {
 };
 
 typedef NS_ENUM(NSInteger, RNCameraWhiteBalance) {
+    RNCameraWhiteBalanceCustom = -1,
     RNCameraWhiteBalanceAuto = 0,
     RNCameraWhiteBalanceSunny = 1,
     RNCameraWhiteBalanceCloudy = 2,

ios/RN/RNCameraManager.m

@@ -51,6 +51,7 @@ RCT_EXPORT_VIEW_PROPERTY(videoStabilizationMode, NSInteger);
              @"AutoFocus" :
                  @{@"on" : @(RNCameraAutoFocusOn), @"off" : @(RNCameraAutoFocusOff)},
              @"WhiteBalance" : @{
+                     @"custom" : @(RNCameraWhiteBalanceCustom),
                      @"auto" : @(RNCameraWhiteBalanceAuto),
                      @"sunny" : @(RNCameraWhiteBalanceSunny),
                      @"cloudy" : @(RNCameraWhiteBalanceCloudy),
@@ -233,6 +234,13 @@ RCT_CUSTOM_VIEW_PROPERTY(whiteBalance, NSInteger, RNCamera)
     [view updateWhiteBalance];
 }
 
+RCT_CUSTOM_VIEW_PROPERTY(customWhiteBalance, NSDictionary *, RNCamera)
+{
+    [view setWhiteBalance:RNCameraWhiteBalanceCustom];
+    [view setCustomWhiteBalance:[RCTConvert NSDictionary:json]];
+    [view updateWhiteBalance];
+}
+
 RCT_CUSTOM_VIEW_PROPERTY(exposure, NSNumber, RNCamera)
 {
     [view setExposure:[RCTConvert float:json]];

src/RNCamera.js

@@ -270,6 +270,7 @@ type PropsType = typeof View.props & {
   googleVisionBarcodeType?: number,
   googleVisionBarcodeMode?: number,
   whiteBalance?: number | string,
+  customWhiteBalance?: {temperature: number, tint: number, redGainOffset?: number, greenGainOffset?: number, blueGainOffset?: number },
   faceDetectionLandmarks?: number,
   autoFocus?: string | boolean | number,
   autoFocusPointOfInterest?: { x: number, y: number },
@@ -418,6 +419,10 @@ export default class Camera extends React.Component<PropsType, StateType> {
     flashMode: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
     exposure: PropTypes.number,
     whiteBalance: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
+    customWhiteBalance: PropTypes.shape({temperature: PropTypes.number, tint: PropTypes.number,
+      redGainOffset: PropTypes.number,
+      greenGainOffset: PropTypes.number,
+      blueGainOffset: PropTypes.number }),
     autoFocus: PropTypes.oneOfType([PropTypes.string, PropTypes.number, PropTypes.bool]),
     autoFocusPointOfInterest: PropTypes.shape({ x: PropTypes.number, y: PropTypes.number }),
     permissionDialogTitle: PropTypes.string,
@@ -448,6 +453,7 @@ export default class Camera extends React.Component<PropsType, StateType> {
     flashMode: CameraManager.FlashMode.off,
     exposure: -1,
     whiteBalance: CameraManager.WhiteBalance.auto,
+    customWhiteBalance: null,
     faceDetectionMode: (CameraManager.FaceDetection || {}).fast,
     barCodeTypes: Object.values(CameraManager.BarCodeType),
     googleVisionBarcodeType: ((CameraManager.GoogleVisionBarcodeDetection || {}).BarcodeType || {})

types/index.d.ts

@@ -32,6 +32,7 @@ type WhiteBalance = Readonly<{
   incandescent: any;
   fluorescent: any;
   auto: any;
+  custom: any;
 }>;
 type BarCodeType = Readonly<{
   aztec: any;
@@ -147,6 +148,8 @@ export interface RNCameraProps {
   useCamera2Api?: boolean;
   exposure?: number;
   whiteBalance?: keyof WhiteBalance;
+  customWhiteBalance?: {temperature: number; tint: number; redGainOffset?: number; greenGainOffset?: number; blueGainOffset?: number };
+
   captureAudio?: boolean;
 
   onCameraReady?(): void;