ArcGISRuntime.UWP.Samples.AuthorMap.AuthorMap.WriteTempThumbnailImageAsync C# (CSharp) Метод

        private async Task<string> WriteTempThumbnailImageAsync(ImageSource mapImageSource)
        {
            string outputFilename = string.Empty;

            try
            {
                // Export the current map view display to a bitmap
                var mapImage = mapImageSource as WriteableBitmap;

                // Create a new file in the device's Pictures folder
                var outStorageFile = await KnownFolders.PicturesLibrary.CreateFileAsync("MapImage_Temp.jpg", CreationCollisionOption.GenerateUniqueName);
                outputFilename = outStorageFile.Name;

                // Open the new file for read/write
                using (var stream = await outStorageFile.OpenAsync(FileAccessMode.ReadWrite))
                {
                    // Create a bitmap encoder to encode the image to Jpeg
                    var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream);

                    // Read the pixels from the map image into a byte array
                    var pixelStream = mapImage.PixelBuffer.AsStream();
                    var pixels = new byte[pixelStream.Length];
                    await pixelStream.ReadAsync(pixels, 0, pixels.Length);

                    // Use the encoder to write the map image pixels to the output file
                    encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, (uint)mapImage.PixelWidth, (uint)mapImage.PixelHeight, 96.0, 96.0, pixels);
                    await encoder.FlushAsync();
                }
            }
            catch
            {
                // Exception message will be shown in the calling function
                throw;
            }

            return outputFilename;
        }