小賢的部落格

市集應用程式影像處理，遇到最關鍵的地方是如何讀取圖片串流後取得RGBData，後來在MSDN上找到範例程式

public static async Task LoadImage(StorageFile file)
        {
            using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read))
            {
                BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
                // Scale image to appropriate size 
                BitmapTransform transform = new BitmapTransform()
                {
                    ScaledWidth = Convert.ToUInt32(decoder.PixelWidth),
                    ScaledHeight = Convert.ToUInt32(decoder.PixelHeight)
                };
                PixelDataProvider pixelData = await decoder.GetPixelDataAsync(
                    BitmapPixelFormat.Bgra8, // WriteableBitmap uses BGRA format 
                    BitmapAlphaMode.Straight,
                    transform,
                    ExifOrientationMode.IgnoreExifOrientation, // This sample ignores Exif orientation 
                    ColorManagementMode.DoNotColorManage
                );

                // An array containing the decoded image data, which could be modified before being displayed 
                byte[] sourcePixels = pixelData.DetachPixelData();

                // Open a stream to copy the image contents to the WriteableBitmap's pixel buffer await SetImage(decoder, sourcePixels, gray);
                return new
               {
                    rgbData = sourcePixels,
                    Width = decoder.PixelWidth,
                    Height = decoder.PixelHeight
                };
            }
        }