iOS:相机方向 [英] iOS: camera orientation

问题描述

我想使用 AVCaptureSession 用相机捕捉图像.

I want to capture an image with the camera using AVCaptureSession.

它工作正常，我启动相机，我可以得到输出.但是，我在旋转设备时遇到了一些视频方向问题.

It works ok, I start the camera and I can get the output. However, I have some problems with video orientation when I rotate the device.

首先，我想支持横向左右方向，以后也可能是纵向模式.

First, I want to support landscape left and right orientations and may be portrait modes too later.

我执行:

- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation) interfaceOrientation{ 
return UIInterfaceOrientationIsLandscapse(interfaceOrientation);
}

当我旋转设备时，它会将应用程序从左侧横向旋转到右侧，反之亦然，但我只有在左侧横向时才能正确看到相机.当应用处于横向右侧时，视频会旋转 180 度.

When I rotate the device, it rotates the app from landscape left to landscape right or vice versa, but I only see the camera correctly when I'm on landscape left. When the app is on landscape right, the video is rotated by 180 degrees.

非常感谢.

更新:

我已经尝试了 Spectravideo328 的答案，但是当我尝试旋转设备并且应用程序崩溃时出现错误.这是错误:

I've tried Spectravideo328 answer but I have an error when I try to rotate the device and the app crash. This is the error:

[AVCaptureVideoPreviewLayer connection]: unrecognized selector sent to instance 0xf678210

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[AVCaptureVideoPreviewLayer connection]: unrecognized selector sent to instance 0xf678210'

错误出现在这一行:

AVCaptureConnection *previewLayerConnection=self.previewLayer.connection;

我把它放在 shouldAutorotateToInterfaceOrientation 方法里面.你知道这个错误可能是什么原因吗?

I put it inside shouldAutorotateToInterfaceOrientation method. Do you know what could be the reason of this error?

谢谢

推荐答案

奇怪的是，默认的相机方向是 UIInterfaceOrientationLeft.

The default camera orientation is oddly enough UIInterfaceOrientationLeft.

相机方向不会随着设备的旋转而改变.他们是分开的.您必须手动调整相机方向:

The camera orientation does not change with the rotation of the device. They are separate. You have to adjust the camera orientation manually:

将以下内容放入您传递给 toInterfaceOrientation 的方法中(也许您从上面的 shouldAutorotateToInterfaceOrientation 调用它，以便设备旋转和相机旋转):

Put the following in a method that you pass toInterfaceOrientation to (maybe you call it from shouldAutorotateToInterfaceOrientation above so that the device rotates and the camera rotates):

你必须先获得预览层连接

You have to get the preview Layer connection first

AVCaptureConnection *previewLayerConnection=self.previewLayer.connection;

if ([previewLayerConnection isVideoOrientationSupported])
{
    switch (toInterfaceOrientation)
    {
        case UIInterfaceOrientationPortrait:
            [previewLayerConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
            break;
        case UIInterfaceOrientationLandscapeRight:
            [previewLayerConnection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight]; //home button on right. Refer to .h not doc
            break;
        case UIInterfaceOrientationLandscapeLeft:
            [previewLayerConnection setVideoOrientation:AVCaptureVideoOrientationLandscapeLeft]; //home button on left. Refer to .h not doc
            break;
        default:
            [previewLayerConnection setVideoOrientation:AVCaptureVideoOrientationPortrait]; //for portrait upside down. Refer to .h not doc
            break;
    }
}

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