iphone - AVLayerVideoGravityResizeAspectFill 在哪里裁剪

Question

我正在使用AVCaptureSession带有重力AVCaptureVideoPreviewLayer的a。AVLayerVideoGravityResizeAspectFill

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

如何知道如何调整视频大小以适应预览区域AVLayerVideoGravityResizeAspectFill？图像的哪个部分在预览区域中可见？

从文档：

AVLayerVideoGravityResizeAspectFill：保留纵横比，但填充可用屏幕区域，必要时裁剪视频

基本上，如何准确获取 previewLayer 中显示的内容？

Answer 1

使用iOS 6 SDK，我可以在AVCaptureVideoPreviewLayer

(CGPoint)captureDevicePointOfInterestForPoint:(CGPoint)pointInLayer