HoloLens 2 UWP位图图像伪像

问题描述

我正在构建一个可在HoloLens 2上运行的2D UWP应用。在该应用中，我正在使用rendertargetBitmap渲染视频源UI对象的位图，以从中获取静止图像作为SoftwareBitmap对象。令人沮丧的是，在PC上以x86模式运行它时，它可以正常工作。但是，当我在Hololens 2（ARM）上运行时，图像中会出现乱码，从而使图像变乱。它似乎被分成不匹配的行。我添加了将图像文件保存到设备上的文件夹中的功能，输出的图像看起来不错，但是当在应用程序用户界面中将其设置为imageSource时，它看起来就搞砸了。

在我的VideoControl.xaml.cs代码后面：

    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,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;
    }     

在这方面的任何帮助都将一如既往！

解决方法

这最终解决了它。我需要将位图文件保存到设备中，然后再读回。不理想，但是可以。

    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,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;
            }
        });         
    }