我有一个从相机拉出来的预览图层,它应该是工作的.当我按一个按钮时,我想要拍照.我已经启动了AVCaptureStill
ImageOutput,如下所示：
AVCaptureStillImageOutput *avCaptureImg = [[AVCaptureStillImageOutput alloc] init];
然后我试图用这个对象拍照：
[avCaptureImg captureStillImageAsynchronouslyFromConnection:(AVCaptureConnection *) completionHandler:^(CMSampleBufferRef imageDataSampleBuffer,NSError *error) { }];
我需要帮助如何拍照并将其保存在变量中.谢谢
解决方法
您需要确定定义一个AVCaptureVideoPreviewLayer&将其添加到视图层：
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session]; [self.view.layer addSublayer:captureVideoPreviewLayer];
这将连接到您的AVCaptureDeviceInput
这是完整的解决方案：
/////////////////////////////////////////////////
////
//// Utility to find front camera
////
/////////////////////////////////////////////////
-(AVCaptureDevice *) frontFacingCameraIfAvailable{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices){
if (device.position == AVCaptureDevicePositionFront){
captureDevice = device;
break;
}
}
// couldn't find one on the front,so just get the default video device.
if (!captureDevice){
captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
return captureDevice;
}
/////////////////////////////////////////////////
////
//// Setup Session,attach Video Preview Layer
//// and Capture Device,start running session
////
/////////////////////////////////////////////////
-(void) setupCaptureSession {
AVCaptureSession *session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[self.view.layer addSublayer:captureVideoPreviewLayer];
NSError *error = nil;
AVCaptureDevice *device = [self frontFacingCameraIfAvailable];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(@"ERROR: trying to open camera: %@",error);
}
[session addInput:input];
self.stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG,AVVideoCodecKey,nil];
[self.stillImageOutput setOutputSettings:outputSettings];
[session addOutput:self.stillImageOutput];
[session startRunning];
}
/////////////////////////////////////////////////
////
//// Method to capture Still Image from
//// Video Preview Layer
////
/////////////////////////////////////////////////
-(void) captureNow {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in self.stillImageOutput.connections) {
for (AVCaptureInputPort *port in [connection inputPorts]) {
if ([[port mediaType] isEqual:AVMediaTypeVideo] ) {
videoConnection = connection;
break;
}
}
if (videoConnection) { break; }
}
NSLog(@"about to request a capture from: %@",self.stillImageOutput);
__weak typeof(self) weakSelf = self;
[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer,NSError *error) {
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
[weakSelf displayImage:image];
}];
}
