我正在尝试从 AVCaptureStillImageOutput 捕获像素数据,并注意到在将图像裁剪为 CGImage 后,它会重新定向。为了测试这一点,我将一个临时图像输出到照片库。现在我注意到,即使在图像被裁剪之前,它的缩略图也会旋转,而完整图像则不会。(当我将 UIImage 传递给需要适当尺寸的图像的自定义 pixelDataManager 时,这稍后会成为问题。)
设置captureVideoPreviewLayer.orientation = AVCaptureVideoOrientationPortrait;
,[videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
似乎没有改变任何东西。
有什么想法吗???我会把它分成几部分...
1) 设置会话、输入和输出:
// Create a capture session
AVCaptureSession *session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
// Add capture layer to visible view
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResize;
captureVideoPreviewLayer.frame = screenBounds;
captureVideoPreviewLayer.bounds = screenBounds;
captureVideoPreviewLayer.orientation = AVCaptureVideoOrientationPortrait;
[self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// Setup error handling
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(@"ERROR: trying to open camera: %@", error);
}
[session addInput:input];
// Start session
[session startRunning];
// Output image data
stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];
[session addOutput:stillImageOutput];
2) 设置视频连接:
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in stillImageOutput.connections)
{
for (AVCaptureInputPort *port in [connection inputPorts])
{
if ([[port mediaType] isEqual:AVMediaTypeVideo] )
{
videoConnection = connection;
break;
}
}
if (videoConnection) { break; }
}
if ([videoConnection isVideoOrientationSupported])
{
[videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
}
3)输出捕获的图像:
NSLog(@"about to request a capture from: %@", stillImageOutput);
[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
{
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
//......
}