iphone - AVLayerVideoGravityResizeAspectFill 在哪里裁剪

Question

我正在使用 AVCaptureSession 和 AVCaptureVideoPreviewLayer 以及 AVLayerVideoGravityResizeAspectFill 重力。

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

如何使用 AVLayerVideoGravityResizeAspectFill 了解如何调整视频大小以适应预览区域？图像的哪一部分在预览区域中可见？

来自 the doc :

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

基本上，如何准确获取 previewLayer 中显示的内容？

Answer 1

随着iOS 6 SDK I can use the following在 AVCaptureVideoPreviewLayer

中

(CGPoint)captureDevicePointOfInterestForPoint:(CGPoint)pointInLayer