当我把变焦中心移到左下方

我正在开发一个iOS应用程序与最新的SDK。

我正在使用相机，我想缩放。 要做到这一点，我有这样的代码：

- (void) viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; [self setUpVideo]; } - (void)setUpVideo { NSLog(@"Set up video"); UIView *view = [self videoPreviewView]; CALayer *viewLayer = [view layer]; [viewLayer setMasksToBounds:YES]; AVCaptureVideoPreviewLayer *newCaptureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:DataExchanger.cameraManager.captureSession]; CGRect bounds = [view bounds]; UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation; CGAffineTransform t; if (orientation == UIInterfaceOrientationLandscapeRight) { t = CGAffineTransformMakeRotation(-M_PI_2); bounds = CGRectMake(bounds.origin.x, bounds.origin.y, bounds.size.height, bounds.size.width); } [newCaptureVideoPreviewLayer setFrame:bounds]; [newCaptureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; newCaptureVideoPreviewLayer.position = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds)); newCaptureVideoPreviewLayer.affineTransform = t; [viewLayer insertSublayer:newCaptureVideoPreviewLayer below:[[viewLayer sublayers] objectAtIndex:0]]; CGAffineTransform currentTransform = CGAffineTransformIdentity; CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, 2.0f, 2.0f); view.transform = newTransform; } 

但是，我看到缩放图像和相同的图像之间不同的缩放。 在不移动相机的情况下，当我进行变焦时，我看到中心向左移动。

也许我必须用一个公式来移动videoView中心，用公式计算它的新中心。

你知道如何解决这个问题吗？