Added adjusting exposures message in delegate.

Library/Sources/SCRecorder.h

@@ -189,6 +189,16 @@
  */
 @property (assign, nonatomic) BOOL keepMirroringOnWrite;
 
+/**
+ Whether adjusting exposure is supported on the current camera device
+ */
+@property (readonly, nonatomic) BOOL exposureSupported;
+
+/**
+ The current exposure point of interest
+ */
+@property (readonly, nonatomic) CGPoint exposurePointOfInterest;
+
 /**
  Whether the focus is supported on the current camera device
  */

Library/Sources/SCRecorder.m

@@ -9,10 +9,6 @@
 #import "SCRecorder.h"
 #import "SCRecordSession_Internal.h"
 #define dispatch_handler(x) if (x != nil) dispatch_async(dispatch_get_main_queue(), x)
-#define SCRecorderFocusContext ((void*)0x1)
-#define SCRecorderVideoEnabledContext ((void*)0x2)
-#define SCRecorderAudioEnabledContext ((void*)0x3)
-#define SCRecorderPhotoOptionsContext ((void*)0x3)
 #define kSCRecorderRecordSessionQueueKey "SCRecorderRecordSessionQueue"
 #define kMinTimeBetweenAppend 0.004
 
@@ -49,6 +45,12 @@ @interface SCRecorder() {
 
 @implementation SCRecorder
 
+static char* SCRecorderFocusContext = "FocusContext";
+static char* SCRecorderExposureContext = "ExposureContext";
+static char* SCRecorderVideoEnabledContext = "VideoEnabledContext";
+static char* SCRecorderAudioEnabledContext = "AudioEnabledContext";
+static char* SCRecorderPhotoOptionsContext = "PhotoOptionsContext";
+
 - (id)init {
     self = [super init];
 
@@ -333,7 +335,11 @@ - (void)stopRunning {
 }
 
 - (void)_subjectAreaDidChange {
-    [self focusCenter];
+    id<SCRecorderDelegate> delegate = self.delegate;
+
+    if (![delegate respondsToSelector:@selector(recorderShouldAutomaticallyRefocus:)] || [delegate recorderShouldAutomaticallyRefocus:self]) {
+        [self focusCenter];        
+    }
 }
 
 - (UIImage *)_imageFromSampleBufferHolder:(SCSampleBufferHolder *)sampleBufferHolder {
@@ -875,6 +881,18 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
         } else {
             [self _focusDidComplete];
         }
+    } else if (context == SCRecorderExposureContext) {
+        BOOL isAdjustingExposure = [[change objectForKey:NSKeyValueChangeNewKey] boolValue];
+
+        if (isAdjustingExposure) {
+            if ([delegate respondsToSelector:@selector(recorderDidStartAdjustingExposure:)]) {
+                [delegate recorderDidStartAdjustingExposure:self];
+            }            
+        } else {
+            if ([delegate respondsToSelector:@selector(recorderDidEndAdjustingExposure:)]) {
+                [delegate recorderDidEndAdjustingExposure:self];
+            }
+        }
     } else if (context == SCRecorderAudioEnabledContext) {
         if ([NSThread isMainThread]) {
             [self reconfigureVideoInput:NO audioInput:YES];
@@ -898,10 +916,12 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
 
 - (void)addVideoObservers:(AVCaptureDevice*)videoDevice {
     [videoDevice addObserver:self forKeyPath:@"adjustingFocus" options:NSKeyValueObservingOptionNew context:SCRecorderFocusContext];
+    [videoDevice addObserver:self forKeyPath:@"adjustingExposure" options:NSKeyValueObservingOptionNew context:SCRecorderExposureContext];
 }
 
 - (void)removeVideoObservers:(AVCaptureDevice*)videoDevice {
     [videoDevice removeObserver:self forKeyPath:@"adjustingFocus"];
+    [videoDevice removeObserver:self forKeyPath:@"adjustingExposure"];
 }
 
 - (void)configureDevice:(AVCaptureDevice*)newDevice mediaType:(NSString*)mediaType error:(NSError**)error {
@@ -1070,6 +1090,7 @@ - (void)_applyPointOfInterest:(CGPoint)point continuousMode:(BOOL)continuousMode
     NSError *error;
     if ([device lockForConfiguration:&error]) {
         BOOL focusing = NO;
+        BOOL adjustingExposure = NO;
 
         if (device.isFocusPointOfInterestSupported) {
             device.focusPointOfInterest = point;
@@ -1085,6 +1106,7 @@ - (void)_applyPointOfInterest:(CGPoint)point continuousMode:(BOOL)continuousMode
 
         if ([device isExposureModeSupported:exposureMode]) {
             device.exposureMode = exposureMode;
+            adjustingExposure = YES;
         }
 
         if ([device isWhiteBalanceModeSupported:whiteBalanceMode]) {
@@ -1093,14 +1115,20 @@ - (void)_applyPointOfInterest:(CGPoint)point continuousMode:(BOOL)continuousMode
 
         [device unlockForConfiguration];
 
+        id<SCRecorderDelegate> delegate = self.delegate;
         if (focusMode != AVCaptureFocusModeContinuousAutoFocus && focusing) {
-            id<SCRecorderDelegate> delegate = self.delegate;
             if ([delegate respondsToSelector:@selector(recorderWillStartFocus:)]) {
                 [delegate recorderWillStartFocus:self];
             }
 
             [self setAdjustingFocus:YES];
         }
+
+        if (exposureMode != AVCaptureExposureModeContinuousAutoExposure && adjustingExposure) {
+            if ([delegate respondsToSelector:@selector(recorderWillStartAdjustingExposure:)]) {
+                [delegate recorderWillStartAdjustingExposure:self];
+            }
+        }
     }
 }
 
@@ -1124,6 +1152,14 @@ - (void)refocus {
     [self autoFocusAtPoint:self.focusPointOfInterest];
 }
 
+- (CGPoint)exposurePointOfInterest {
+    return [self.currentVideoDeviceInput device].exposurePointOfInterest;
+}
+
+- (BOOL)exposureSupported {
+    return [self.currentVideoDeviceInput device].isExposurePointOfInterestSupported;
+}
+
 - (CGPoint)focusPointOfInterest {
     return [self.currentVideoDeviceInput device].focusPointOfInterest;
 }

Library/Sources/SCRecorderDelegate.h

@@ -38,6 +38,12 @@ typedef NS_ENUM(NSInteger, SCFlashMode) {
  */
 - (void)recorder:(SCRecorder *__nonnull)recorder didChangeFlashMode:(SCFlashMode)flashMode error:(NSError *__nullable)error;
 
+/**
+ Called when the recorder has lost the focus. Returning true will make the recorder
+ automatically refocus at the center.
+ */
+- (BOOL)recorderShouldAutomaticallyRefocus:(SCRecorder *__nonnull)recorder;
+
 /**
  Called before the recorder will start focusing
  */
@@ -53,6 +59,21 @@ typedef NS_ENUM(NSInteger, SCFlashMode) {
  */
 - (void)recorderDidEndFocus:(SCRecorder *__nonnull)recorder;
 
+/**
+ Called before the recorder will start adjusting exposure
+ */
+- (void)recorderWillStartAdjustingExposure:(SCRecorder *__nonnull)recorder;
+
+/**
+ Called when the recorder has started adjusting exposure
+ */
+- (void)recorderDidStartAdjustingExposure:(SCRecorder *__nonnull)recorder;
+
+/**
+ Called when the recorder has finished adjusting exposure
+ */
+- (void)recorderDidEndAdjustingExposure:(SCRecorder *__nonnull)recorder;
+
 /**
  Called when the recorder has initialized the audio in a session
  */

Library/Sources/SCRecorderToolsView.m

@@ -96,7 +96,15 @@ - (void)layoutSubviews {
 }
 
 - (void)adjustFocusView {
-    CGPoint currentFocusPoint = [self.recorder convertPointOfInterestToViewCoordinates:self.recorder.focusPointOfInterest];
+    CGPoint currentFocusPoint = CGPointMake(0.5, 0.5);
+
+    if (self.recorder.focusSupported) {
+        currentFocusPoint = self.recorder.focusPointOfInterest;
+    } else if (self.recorder.exposureSupported) {
+        currentFocusPoint = self.recorder.exposurePointOfInterest;
+    }
+
+    [self.recorder convertPointOfInterestToViewCoordinates:currentFocusPoint];
     currentFocusPoint = [self convertPoint:currentFocusPoint fromView:self.recorder.previewView];
     self.cameraFocusTargetView.center = currentFocusPoint;
 }