AVCaptureDevice的几个属性

AVCaptureDevice.h，主要用来获取iphone一些关于相机设备的属性。

AVCaptureDevice.h，必须要引入AVFoundation.framework包。

1. 前置和后置摄像头

enum {
    AVCaptureDevicePositionBack = ,
    AVCaptureDevicePositionFront =
};
typedef NSInteger AVCaptureDevicePosition;

2. 闪光灯开关

enum {
    AVCaptureFlashModeOff = ,
    AVCaptureFlashModeOn = ,
    AVCaptureFlashModeAuto =
};
typedef NSInteger AVCaptureFlashMode;

3. 手电筒开关

enum {
    AVCaptureTorchModelOff = ,
    AVCaptureTorchModelOn = ,
    AVCaptureTorchModeAuto =
};
typedef NSInteger AVCaptureTorchMode;

4. 焦距调整

enum {
    AVCaptureFocusModelLocked = ,
    AVCaptureFocusModeAutoFocus = ,
    AVCaptureFocusModeContinousAutoFocus =
};
typedef NSInteger AVCaptureFocusMode;

5. 曝光量调节

enum {
    AVCaptureExposureModeLocked = ,
    AVCaptureExposureModeAutoExpose = ,
    AVCaptureExposureModeContinuousAutoExposure =
};
typedef NSInteger AVCaptureExposureMode;

6. 白平衡

enum {
    AVCaptureWhiteBalanceModeLocked = ,
    AVCaptureWhiteBalanceModeAutoWhiteBalance = ,
    AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance =
};
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) {    
       // log err and handle... 
} else {   
      // flip on the flash mode    
      if ([d hasFlash] && [d isFlashModeSupported:AVCaptureFlashModeOn] ) 
      {       
             [d setFlashMode:AVCaptureFlashModeOn];    
      }

    [d unlockForConfiguration]; 
}