AVCaptureVideoPreviewLayer在iOS中添加叠加并捕获照片 [英] AVCaptureVideoPreviewLayer add overlays and capture photo in iOS

问题描述

最初的想法是通过AVCaptureSession启动摄像机流，在原始CMSampleBuffer中找到人脸，然后在AVCaptureVideoPreviewLayer上添加一些图像作为图层，然后进行截图.

The initial idea was to start a camera stream via AVCaptureSession, find faces in that raw CMSampleBuffer and then add some images as layers on AVCaptureVideoPreviewLayer and then take a screenshot.

完成此操作后，后来发现UIGraphicsGetImageFromCurrentImageContext无法与AVCaptureVideoPreviewLayer配合使用，因此在此处截屏无法解决我的目的.

After completing that, found out later that the UIGraphicsGetImageFromCurrentImageContext won't work with AVCaptureVideoPreviewLayer, so taking screenshot would not solve my purpose here.

因此，我改用了Metal和MTKView来执行一些实时渲染，并且结合使用CoreImage滤镜和Metal可以获得很好的效果.我已经知道如何使用内置的CoreImage滤镜检测面部并更改面部的该部分，但是我找不到合适的方法将一张图像添加到另一张图像上.

So I used Metal and MTKView instead to perform some live rendering and the results are good with the combination of CoreImage Filters and Metal. I already know how to detect faces and alter that part of the face using inbuilt CoreImage filters but I can't find a suitable method to add an image on to another image.

如何相对于背景图像中的位置融合两个图像?我有与CIImage合作.

How can I blend two images with respect to positioning in the background image? I have CIImage to work with.

推荐答案

您可以将叠加层加载到CIImage中，然后使用transformed(by matrix: CGAffineTransform)将其移动到面部位置，最后使用composited(over dest: CIImage)进行混合通过视频缓冲区中的CIImage. 您可能需要进行一些工作才能在不同的坐标空间之间进行转换.

You can load your overlay into a CIImage, then use transformed(by matrix: CGAffineTransform) to move it to the face position, and finally use composited(over dest: CIImage) to blend it over the CIImage from the video buffer. You probably have to put in some work to transfer between the different coordinate spaces.

还有许多更复杂的合成过滤器可用.在CICategoryCompositeOperation类别中查看过滤器.

There are also a lot of more complex compositing filters available. Check out the filters in the CICategoryCompositeOperation category.

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