第六篇 自定义相机 AVCaptureDevice

通过AVCaptureDevice获取设备的摄像头来 自定义相机

不说废话，直接看代码。self 是一个ImageView， 需要再添加到其他ViewController上

初始化

    _session = [[AVCaptureSession alloc] init];   //初始化AVCaptureSession 用来设置输入输出设备属性
    [_session beginConfiguration];// beginConfiguration与commitConfiguration成对出现
    //-- Set preset session size.
    [_session setSessionPreset:_sessionPreset]; //设置采集设备大小 iphone为AVCaptureSessionPreset640x480 iPad为AVCaptureSessionPreset1280x720
    _currentDevicePosition = AVCaptureDevicePositionBack; //后摄像头
    //添加输入设备
    [self addInput];
//添加输出设备
    captureOutput = [[AVCaptureStillImageOutput alloc] init];
    captureOutput = [NSDictionary dictionaryWithObjectsAndKeys:
                                     AVVideoCodecJPEG, AVVideoCodecKey,
                                     nil
                                     ];
    [_session addOutput:captureOutput];
    [_session commitConfiguration];

    _previewLayer = [[AVCaptureVideoPreviewLayer