2018-07-04 有用的代码

实现摄像头反转的代码，以后可能会用到着

- (void)swapFrontAndBackCameras:(AVCaptureSession*)mySession{

    NSArray*inputs =mySession.inputs;

    for(AVCaptureDeviceInput*inputininputs ) {

        AVCaptureDevice*device = input.device;

        if ( [device hasMediaType:AVMediaTypeVideo] ) {

            AVCaptureDevicePositionposition = device.position;

            AVCaptureDevice*newCamera =nil;

            AVCaptureDeviceInput*newInput =nil;

            if (position ==AVCaptureDevicePositionFront)

                newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];

            else

                newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];

            newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];

            [mySessionbeginConfiguration];

            [mySessionremoveInput:input];

            [mySessionaddInput:newInput];

            [mySessioncommitConfiguration];

            break;

        }

    }

}

- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position{

    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];

    for(AVCaptureDevice*deviceindevices )

        if( device.position== position )

            returndevice;

    return nil;

}

//打开和关闭闪光灯

- (void)flashSwitch:(UIButton*)button {

    if(self.input!=nil) {

        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

        if([devicehasTorch] && [devicehasFlash]){

            [devicelockForConfiguration:nil];

            BOOLselected = [buttonisSelected];

            AVCaptureFlashModemodel = device.flashMode;

            if(model !=AVCaptureFlashModeOff) {

                [devicesetTorchMode:AVCaptureTorchModeOff];

                [devicesetFlashMode:AVCaptureFlashModeOff];

            }

            else{

                [devicesetTorchMode:AVCaptureTorchModeOn];

                [devicesetFlashMode:AVCaptureFlashModeOn];

            }

            button.selected= !selected;

            [deviceunlockForConfiguration];

        }

    }

}

//获取一定尺寸的宽度和高度

#define COMPONENT_WIDTH(width) (width * SCREEN_WIDTH /750.0)

#define COMPONENT_HEIGHT(height) (height * SCREEN_HEIHGT /1334.0)