小编mum*_*umu的帖子

我正在尝试将sampleBuffer转换为UIImage并使用colorspaceGray在图像视图中显示它.但它显示为以下图像.这个问题出了什么问题？如何转换CMSampleBuffer？

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    print("buffered")
    let imageBuffer: CVImageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
    CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
    let width: Int = CVPixelBufferGetWidth(imageBuffer)
    let height: Int = CVPixelBufferGetHeight(imageBuffer)
    let bytesPerRow: Int = CVPixelBufferGetBytesPerRow(imageBuffer)
    let lumaBuffer = CVPixelBufferGetBaseAddress(imageBuffer)

    //let planeCount : Int = CVPixelBufferGetPlaneCount(imageBuffer)
    let grayColorSpace: CGColorSpace = CGColorSpaceCreateDeviceGray()
    let context: CGContext = CGContext(data: lumaBuffer, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow , space: grayColorSpace, bitmapInfo: CGImageAlphaInfo.none.rawValue)!
    let dstImageFilter: CGImage = context.makeImage()!
    let imageRect : CGRect = …

我尝试使用 swiftUI 实现一个滚动视图。在滚动视图中有一个包含另一个视图的水平堆栈（HStack）。我希望滚动视图水平滚动。但它也垂直滚动。以下是我的代码：

struct categoryRow : View {
var categoryName: String
var landmarks : [Landmark]
var body: some View {
    VStack(alignment: .leading){
        Text(categoryName).font(.headline).padding(EdgeInsets(top: 15, leading: 10, bottom: 0, trailing: 0))
        ScrollView (alwaysBounceHorizontal: true, showsHorizontalIndicator: false, showsVerticalIndicator: false ){
            HStack(spacing: 15){
                ForEach(landmarks) { landmark in
                    NavigationButton(destination: LandMarkDetails(landmark: landmark)) {
                        CategoryItem(landmark: landmark)
                    }
                }
            }.padding()
        }.frame( height: 190)
    }
}
}

我还没有找到任何选项来停止垂直滚动。我在这里缺少什么？

我建立了一个相机应用程序来自动捕获。我想在打开相机的同时一直保持闪光灯打开。我设置以下代码：

 cameraDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
    if (cameraDevice.hasTorch) {
        do {
            try cameraDevice.lockForConfiguration()

            if cameraDevice.isTorchActive {
                cameraDevice.torchMode = AVCaptureTorchMode.on

            } else {
                // sets the torch intensity to 100%
               try  cameraDevice.setTorchModeOnWithLevel(0.8)
            }

            cameraDevice.unlockForConfiguration()
        } catch {
            print(error)
        }
    }

但是，当我运行该应用程序时，它只会闪烁一次，然后熄灭。我怎么解决这个问题？

我正在尝试将 UIImage 转换为灰度。它所产生的只是一个完全黑色的图像。

func convertToGrayScale2(image: UIImage) -> UIImage {
    let imageRect:CGRect = CGRect(x:0, y:0, width:image.size.width, height: image.size.height)
    let colorSpace = CGColorSpaceCreateDeviceGray()
    let width = image.size.width
    let height = image.size.height

    let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue)
    let context = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfo.rawValue)
    let imageRef = context!.makeImage()
    context?.draw(imageRef!, in: imageRect)
    let newImage = UIImage(cgImage: imageRef!)

    return newImage
}

代码有什么问题吗？我需要现有代码的帮助。它之前正在工作。突然它不工作了。