HoloLens 2 UWP 位图图像伪像

Question

我正在构建一个 2D UWP 应用程序以在 HoloLens 2 上运行。在应用程序中，我使用 RenderTargetBitmap 来渲染视频源 UI 对象的位图，以从中获取作为 SoftwareBitmap 对象的静止图像。 令人沮丧的部分是，在 PC 上以 x86 模式运行它时，它工作正常。 但是，当我在 Hololens 2 (ARM) 上运行时，图像会出现乱码，并且出现了弄乱图像的伪像。 它似乎被分成了不匹配的行。 我添加了将图像文件保存到设备上的文件夹的功能，输出的图像看起来不错，但是当它在应用程序 UI 中设置为 imageSource 时，它​​看起来全都搞砸了。

在我的 VideoControl.xaml.cs 代码隐藏中：

    private static async Task SetPauseImageSource()
    {
        await Instance.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
        {
            SoftwareBitmap image = await Xaml2Bitmap.CreateBitmapFromElement(Instance, true);
            var source = new SoftwareBitmapSource();
            await source.SetBitmapAsync(image);
            Instance.imagePause.Source = source;
        });         
    }

在我的 Xaml2Bitmap.cs 类中：

    public static async Task<SoftwareBitmap> CreateBitmapFromElement(FrameworkElement uielement, bool saveFile = false, string filenamePrefix = "image")
    {           
        SoftwareBitmap bitmap = null;
        var renderTargetBitmap = new RenderTargetBitmap();
        await renderTargetBitmap.RenderAsync(uielement);
        var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();
        bitmap = SoftwareBitmap.CreateCopyFromBuffer(pixelBuffer, BitmapPixelFormat.Bgra8, (int)uielement.ActualWidth, (int)uielement.ActualHeight, BitmapAlphaMode.Ignore);

        if (bitmap == null)
        {
            Debug.WriteLine("Bitmap is null");
        }

        if (saveFile)
        {
            var file = await SaveFile(filenamePrefix);

            using (var stream = await file.OpenAsync(FileAccessMode.ReadWrite))
            {
                var logicalDpi = DisplayInformation.GetForCurrentView().LogicalDpi;
                var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream);
                encoder.SetPixelData(
                    BitmapPixelFormat.Bgra8,
                    BitmapAlphaMode.Ignore,
                    (uint)renderTargetBitmap.PixelWidth,
                    (uint)renderTargetBitmap.PixelHeight,
                    logicalDpi,
                    logicalDpi,
                    pixelBuffer.ToArray());
                        
                await encoder.FlushAsync();
            }
        }
        return bitmap;
    }

    private static async Task<StorageFile> SaveFile(string filenamePrefix)
    {
        var savePicker = new FileSavePicker();
        savePicker.DefaultFileExtension = ".png";
        savePicker.FileTypeChoices.Add(".png", new List<string> { ".png" });
        savePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
        savePicker.SuggestedFileName = filenamePrefix + ".png";

        // Prompt the user to select a file
        var saveFile = await savePicker.PickSaveFileAsync();
        return saveFile;
    }     

一如既往地感谢您对此的任何帮助！

Answer 1

这最终修复了它。 我需要将位图文件保存到设备并重新读取它。不理想但它有效。

    public static async Task<string> CreateBitmapFromElement(FrameworkElement uielement)
    {
        SoftwareBitmap bitmap = null;
        var renderTargetBitmap = new RenderTargetBitmap();
        await renderTargetBitmap.RenderAsync(uielement);
        var pixelBuffer = await renderTargetBitmap.GetPixelsAsync();
        bitmap = SoftwareBitmap.CreateCopyFromBuffer(pixelBuffer, BitmapPixelFormat.Bgra8, (int)uielement.ActualWidth, (int)uielement.ActualHeight, BitmapAlphaMode.Ignore);

        if (bitmap == null)
        {
            Debug.WriteLine("Bitmap is null");
        }

        var folder = KnownFolders.PicturesLibrary; 
        var file = await folder.CreateFileAsync("pause.bmp", CreationCollisionOption.ReplaceExisting);
       
        using (var stream = await file.OpenAsync(FileAccessMode.ReadWrite))
        {
            var logicalDpi = DisplayInformation.GetForCurrentView().LogicalDpi;
            var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream);
            encoder.SetPixelData(
                BitmapPixelFormat.Bgra8,
                BitmapAlphaMode.Ignore,
                (uint)renderTargetBitmap.PixelWidth,
                (uint)renderTargetBitmap.PixelHeight,
                logicalDpi,
                logicalDpi,
                pixelBuffer.ToArray());

            await encoder.FlushAsync();


            await stream.WriteAsync(pixelBuffer);

        }

        return file.Name;
    }

    private static async Task SetImageSource()
    {
        await Instance.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
        {
            StorageFolder storageFolder = KnownFolders.PicturesLibrary;
            string imagePath = await Xaml2Bitmap.CreateBitmapFromElement(Instance);
            var file = await storageFolder.GetFileAsync(imagePath);

            using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read))
            {
                BitmapImage bitmapImage = new BitmapImage();
                await bitmapImage.SetSourceAsync(fileStream);
                Instance.imagePause.Source = bitmapImage;
            }
        });         
    }