在基本的GPUImage2相机设置中从未调用过imageAvailableCallback [英] imageAvailableCallback never called in basic GPUImage2 camera setup

问题描述

我已按照GPUImage2的github上的基本设置说明进行操作，过滤实时视频和从视频中捕获图像只是为了设置基本的相机。当用户点击按钮时，我尝试使用以下代码专门从过滤器捕获图像：

I have followed the basic setup instructions on GPUImage2's github for filtering live video and capturing an image from video just so I can setup a basic camera. When the user taps a button, I try to capture the image from the filter using this code specifically:

    let pictureOutput = PictureOutput()
    pictureOutput.encodedImageFormat = .JPEG
    pictureOutput.imageAvailableCallback = {image in
        // Do something with the image
        self.previewImageView.image = image
    }
    self.filter! --> pictureOutput

无论出于何种原因，都不会调用imageAvailableCallback，并且无法从摄像机获取图像。

For whatever reason, the imageAvailableCallback is never called and I am unable to get the image from the camera.

推荐答案

-> 调用 addTarget 和 addTarget 附加到目标（ TargetContainer ），后者附加弱引用。因此，您应该确保目标在回调中可用。例如，只需将pictureOutput变量放在类的顶部。

The --> calls addTarget and addTarget appends to targets (TargetContainer) which appends a weak reference. So you should make sure the target will be available on callback. For example just place the pictureOutput variable at the top of your class.

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