ios - 来自 gpuimage lib 的 imageFromCurrentFramebuffer 保存黑帧

Question

我正在应用过滤器列表来检测相机捕获过程中的形状。检测到形状后 - 想将其保存到照片中以供查看。 Google 搜索 imageFromCurrentFramebuffer，但总是保存黑色图片。

// camera init
var videoCamera = GPUImageVideoCamera(sessionPreset: AVCaptureSessionPreset1920x1080, cameraPosition: .Back)
videoCamera!.outputImageOrientation = .Portrait;
videoCamera?.startCameraCapture()

// filter init
var houghTransformFilter = GPUImageHoughTransformLineDetector()
houghTransformFilter!.lineDetectionThreshold = 0.3
houghTransformFilter!.useNextFrameForImageCapture() //without this crashes
houghTransformFilter!.linesDetectedBlock = {
    // my custom shape detection logic
    if (found) {
        self.videoCamera?.pauseCameraCapture()
        var capturedImage:UIImage? = self.houghTransformFilter!.imageFromCurrentFramebuffer()
        UIImageWriteToSavedPhotosAlbum(capturedImage, nil, nil, nil); 
    }

}

Answer 1

我遇到了类似的问题。您可能需要在抓取框架的调用之前添加此行:

self.houghTransformFilter?.useNextFrameForImageCapture()