[UWP]转换为灰度时获得损坏的图像 [英] [UWP] Getting Corrupt image when converting to greyscale

问题描述

我正在尝试捕获图像并转换为灰度。点击移动设备时，我会看到这样的损坏图像，但点击移动设备时也不会发生同样的情况。此外，如果我从图库中选择文件，我会得到适当的灰度图像。

这是我的代码：

 private async void CapturePic_Click（object sender，RoutedEventArgs e）
 { 
 CameraCaptureUI captureUI = new CameraCaptureUI（）; 
 captureUI.PhotoSettings.Format = CameraCaptureUIPhotoFormat.Jpeg; 
 captureUI.PhotoSettings.CroppedSizeInPixels = new Size（200,200）; 
 
 StorageFile photo = await captureUI.CaptureFileAsync（CameraCaptureUIMode.Photo）; 
 
 if（photo == null）
 {
 //用户取消照片拍摄
返回; 
} 
 
 BitmapImage Image = await StorageFileToBitmapImage（photo）; 
 BitmapDecoder decoder = null; 
 using（IRandomAccessStreamWithContentType stream = await photo.OpenReadAsync（））
 {
 decoder = await BitmapDecoder.CreateAsync（stream）; 
 
 //获取第一帧
 BitmapFrame bitmapFrame = await decoder.GetFrameAsync（0）; 
 
 //保存分辨率（稍后将用于保存文件）
 // dpiX = bitmapFrame.DpiX; 
 // dpiY = bitmapFrame.DpiY; 
 
 //获取像素
 PixelDataProvider dataProvider = 
等待bitmapFrame.GetPixelDataAsync（BitmapPixelFormat.Bgra8，
 BitmapAlphaMode.Premultiplied，
 new BitmapTransform（）， 
 ExifOrientationMode.RespectExifOrientation，
 ColorManagementMode.ColorManageToSRgb）; 
 
 byte [] pixels = dataProvider.DetachPixelData（）; 
 
 //创建WriteableBitmap并设置像素
 WriteableBitmap bitmap = new WriteableBitmap（（int）bitmapFrame.PixelWidth，
（int）bitmapFrame.PixelHeight）; 
 
 using（Stream pixelStream = bitmap.PixelBuffer.AsStream（））
 {
 await pixelStream.WriteAsync（pixels，0，pixels.Length）; 
} 
 
 //使WriteableBitmap无效并设置为Image源
 bitmap.Invalidate（）; 
 // image.Source = bitmap; 
 imageControl.Source = bitmap; 
} 
 WriteableBitmap srcBitmap = imageControl.Source as WriteableBitmap; 
 byte [] srcPixels = new byte [4 * srcBitmap.PixelWidth * srcBitmap.PixelHeight]; 
 
使用（Stream pixelStream = srcBitmap.PixelBuffer.AsStream（））
 {
 await pixelStream.ReadAsync（srcPixels，0，srcPixels.Length）; 
} 
 
 //创建目标位图和像素数组
 WriteableBitmap dstBitmap = 
 new WriteableBitmap（srcBitmap.PixelWidth，srcBitmap.PixelHeight）; 
 byte [] dstPixels = new byte [4 * dstBitmap.PixelWidth * dstBitmap.PixelHeight]; 
 
 
 for（int i = 0; i< srcPixels.Length; i + = 4）
 {
 double b =（double）srcPixels [i] / 255.0; 
 double g =（double）srcPixels [i + 1] / 255.0; 
 double r =（double）srcPixels [i + 2] / 255.0; 
 
 byte a = srcPixels [i + 3]; 
 
 double z =（0.21 * r + 0.71 * g + 0.07 * b）* 255; 
 byte f = Convert.ToByte（z）; 
 
 dstPixels [i] = f; 
 dstPixels [i + 1] = f; 
 dstPixels [i + 2] = f; 
 dstPixels [i + 3] = a; 
 
} 
 
 //使用（Stream pixelStream = dstBitmap.PixelBuffer.AsStream（））将像素移动到目标位图
 
 {
等待pixelStream.WriteAsync（dstPixels，0，dstPixels.Length）; 
} 
 dstBitmap.Invalidate（）; 
 
 //显示新位图
 imageControl.Source = dstBitmap; 
 
 
 // imageControl.Source = Image; 
 StorageFolder destinationFolder = 
 await ApplicationData.Current.LocalFolder.CreateFolderAsync（" ProfilePhotoFolder"，
 CreationCollisionOption.OpenIfExists）; 
 
 await photo.CopyAsync（destinationFolder，" ProfilePhoto.jpg"，NameCollisionOption.ReplaceExisting）; 
 await photo.DeleteAsync（）; 
 
} 
公共静态异步任务< BitmapImage> StorageFileToBitmapImage（StorageFile savedStorageFile）
 {
 using（IRandomAccessStream fileStream = await savedStorageFile.OpenAsync（Windows.Storage.FileAccessMode.Read））
 {
 BitmapImage bitmapImage = new BitmapImage（）; 
 bitmapImage.DecodePixelHeight = 28; 
 bitmapImage.DecodePixelWidth = 28; 
等待bitmapImage.SetSourceAsync（fileStream）; 
返回bitmapImage; 
} 
} 

这背后可能是什么原因？

解决方案

我会使用lumia成像sdk并对图像应用灰度滤镜

https://msdn.microsoft.com/library/mt598502.aspx?f=255&MSPPError=-2147217396

I am trying to capture Image and convert to greyscale. I get a corrupt image like this while clicking through mobile but the same doesn't happen when clicking through mobile. Also if i select file from gallery I get proper greyscale image.

Here is My Code:

        private async void CapturePic_Click(object sender, RoutedEventArgs e)
        {
            CameraCaptureUI captureUI = new CameraCaptureUI();
            captureUI.PhotoSettings.Format = CameraCaptureUIPhotoFormat.Jpeg;
            captureUI.PhotoSettings.CroppedSizeInPixels = new Size(200, 200);

            StorageFile photo = await captureUI.CaptureFileAsync(CameraCaptureUIMode.Photo);

            if (photo == null)
            {
                // User cancelled photo capture
                return;
            }
        
            BitmapImage Image = await StorageFileToBitmapImage(photo);
            BitmapDecoder decoder = null;
            using (IRandomAccessStreamWithContentType stream = await photo.OpenReadAsync())
            {
                decoder = await BitmapDecoder.CreateAsync(stream);

                // Get the first frame
                BitmapFrame bitmapFrame = await decoder.GetFrameAsync(0);

                // Save the resolution (will be used for saving the file later)
                // dpiX = bitmapFrame.DpiX;
                //dpiY = bitmapFrame.DpiY;

                // Get the pixels
                PixelDataProvider dataProvider =
                    await bitmapFrame.GetPixelDataAsync(BitmapPixelFormat.Bgra8,
                                                        BitmapAlphaMode.Premultiplied,
                                                        new BitmapTransform(),
                                                        ExifOrientationMode.RespectExifOrientation,
                                                        ColorManagementMode.ColorManageToSRgb);

                byte[] pixels = dataProvider.DetachPixelData();
               
                // Create WriteableBitmap and set the pixels
                WriteableBitmap bitmap = new WriteableBitmap((int)bitmapFrame.PixelWidth,
                                                             (int)bitmapFrame.PixelHeight);

                using (Stream pixelStream = bitmap.PixelBuffer.AsStream())
                {
                    await pixelStream.WriteAsync(pixels, 0, pixels.Length);
                }

                // Invalidate the WriteableBitmap and set as Image source
                bitmap.Invalidate();
                //  image.Source = bitmap;
                imageControl.Source = bitmap;
            }
            WriteableBitmap srcBitmap =  imageControl.Source as WriteableBitmap;
            byte[] srcPixels = new byte[4 * srcBitmap.PixelWidth * srcBitmap.PixelHeight];

            using (Stream pixelStream = srcBitmap.PixelBuffer.AsStream())
            {
                await pixelStream.ReadAsync(srcPixels, 0, srcPixels.Length);
            }

            // Create a destination bitmap and pixels array
            WriteableBitmap dstBitmap =
                    new WriteableBitmap(srcBitmap.PixelWidth, srcBitmap.PixelHeight);
            byte[] dstPixels = new byte[4 * dstBitmap.PixelWidth * dstBitmap.PixelHeight];


            for (int i = 0; i < srcPixels.Length; i += 4)
            {
                double b = (double)srcPixels[i] / 255.0;
                double g = (double)srcPixels[i + 1] / 255.0;
                double r = (double)srcPixels[i + 2] / 255.0;

                byte a = srcPixels[i + 3];

                double z = (0.21 * r + 0.71 * g + 0.07 * b) * 255;
                byte f = Convert.ToByte(z);

                dstPixels[i] = f;
                dstPixels[i + 1] = f;
                dstPixels[i + 2] = f;
                dstPixels[i + 3] = a;

            }

            // Move the pixels into the destination bitmap
            using (Stream pixelStream = dstBitmap.PixelBuffer.AsStream())
            {
                await pixelStream.WriteAsync(dstPixels, 0, dstPixels.Length);
            }
            dstBitmap.Invalidate();

            // Display the new bitmap
            imageControl.Source = dstBitmap;
            

           // imageControl.Source = Image;
            StorageFolder destinationFolder = 
    await ApplicationData.Current.LocalFolder.CreateFolderAsync("ProfilePhotoFolder",
        CreationCollisionOption.OpenIfExists);

            await photo.CopyAsync(destinationFolder, "ProfilePhoto.jpg", NameCollisionOption.ReplaceExisting);
            await photo.DeleteAsync();
            
        }
        public static async Task<BitmapImage> StorageFileToBitmapImage(StorageFile savedStorageFile)
        {
            using (IRandomAccessStream fileStream = await savedStorageFile.OpenAsync(Windows.Storage.FileAccessMode.Read))
            {
                BitmapImage bitmapImage = new BitmapImage();
                bitmapImage.DecodePixelHeight = 28;
                bitmapImage.DecodePixelWidth = 28;
                await bitmapImage.SetSourceAsync(fileStream);
                return bitmapImage;
            }
        }

What could be the reason behind this?

解决方案

I would use the lumia imaging sdk and apply a gray scale filter to the image

https://msdn.microsoft.com/library/mt598502.aspx?f=255&MSPPError=-2147217396

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