学步园

enum {

AVCaptureDevicePositionBack                = 1,

AVCaptureDevicePositionFront               = 2

};

typedef NSInteger AVCaptureDevicePosition;

闪光灯开关

enum {

AVCaptureFlashModeOff  = 0,

AVCaptureFlashModeOn   = 1,

AVCaptureFlashModeAuto = 2

};

typedef NSInteger AVCaptureFlashMode;

手电筒开关

enum {

AVCaptureTorchModeOff  = 0,

AVCaptureTorchModeOn   = 1,

AVCaptureTorchModeAuto = 2,

};

typedef NSInteger AVCaptureTorchMode;

焦距调整

enum {

AVCaptureFocusModeLocked              = 0,

AVCaptureFocusModeAutoFocus           = 1,

AVCaptureFocusModeContinuousAutoFocus = 2,

};

typedef NSInteger AVCaptureFocusMode;

曝光量调节

enum {

AVCaptureExposureModeLocked = 0,

AVCaptureExposureModeAutoExpose = 1,

AVCaptureExposureModeContinuousAutoExposure = 2,

};

typedef NSInteger AVCaptureExposureMode;

白平衡

enum {

AVCaptureWhiteBalanceModeLocked         = 0,

AVCaptureWhiteBalanceModeAutoWhiteBalance         = 1,

    AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance = 2,

};

typedef NSInteger AVCaptureWhiteBalanceMode;

开启闪光灯

AVCaptureDevice* d = nil;

// find a device by position

NSArray* allDevices = [AVCaptureDevice devices];

for (AVCaptureDevice* currentDevice in allDevices) {

  if (currentDevice.position == AVCaptureDevicePositionBack) {

    d = currentDevice;

  }

}

// at this point, d may still be nil, assuming we found something we like....
NSError* err = nil;

BOOL lockAcquired = [d lockForConfiguration:&err];
if (!lockAcquired) {