Where does AVLayerVideoGravityResizeAspectFill crop

Question

I'm using a AVCaptureSession with an AVCaptureVideoPreviewLayer with the AVLayerVideoGravityResizeAspectFill gravity.

self.captureSession =[[AVCaptureSession alloc] init];
captureSession.sessionPreset = AVCaptureSessionPresetPhoto;
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
[self.previewLayer setVideoGravity: AVLayerVideoGravityResizeAspectFill];

How to know how the video will be resized to fit the preview area with the AVLayerVideoGravityResizeAspectFill? Which part of the image is visible in the preview area?

From the doc:

AVLayerVideoGravityResizeAspectFill: This preserves the aspect ratio, but fills the available screen area, cropping the video when necessary

Basically, how to get exactly what was displayed in the previewLayer ?

Answer 1

With the iOS 6 SDK I can use the following in AVCaptureVideoPreviewLayer

(CGPoint)captureDevicePointOfInterestForPoint:(CGPoint)pointInLayer