c# - How to print an image with a thermal printer

Question

I've been following many SO answers and none of them work. This is one of them, and I think is the most promising (the original answer)

        public static async Task PrintImageFilesAsync(BluetoothSocket _socket, IEnumerable<FileResult> imageFiles)
        { 
            foreach(var file in imageFiles) {
                var path = file.FullPath;
                var imageFile = File.Open(path, FileMode.Open, FileAccess.ReadWrite);
                
                Bitmap originalImage = await BitmapFactory.DecodeStreamAsync(imageFile);
                var strippedImage = StripColor(originalImage); // Strips the image of ALL colour, and re-colourizes it all to black.

                using (var memStream = new MemoryStream()) {
                    int bufferLength = (int)imageFile.Length;
                    byte[] buffer = new byte[bufferLength];

                    await strippedImage.CompressAsync(Bitmap.CompressFormat.Jpeg, 0, memStream); // Writes image data to memStream
                    buffer = memStream.ToArray(); // Writes data in memStream to buffer
                    await imageFile.ReadAsync(buffer, 0, bufferLength); // Modifies the buffer IN PLACE
                    try
                    {
                        await _socket.OutputStream.WriteAsync(buffer, 0, bufferLength); // This part is responsible for printing.
                    }
                    catch (Java.IO.IOException ioEx)
                    {
                        originalImage.Dispose();
                        strippedImage.Dispose();

                        memStream.Close();
                        memStream.Dispose();

                        _socket.Close();
                        _socket.Dispose();

                        CrossToastPopUp.Current.ShowToastError($"{ioEx.Message}\nError: {ioEx}");
                        return;
                    }
                    strippedImage.Dispose();
                    originalImage.Dispose();
                }
                var status = "Print job completed.";
                Debug.WriteLine(status);
                CrossToastPopUp.Current.ShowToastMessage(status);
            }
            _socket.Close();
            _socket.Dispose();
        }

The function then strips the image of all color with StripColor

        private static Task<Bitmap> StripColor(Bitmap image)
        {
            image = image.Copy(Bitmap.Config.Argb8888, true);
            try
            {
                image.EraseColor(0);
            }
            catch (Java.Lang.IllegalStateException isEx)
            {
                Debug.WriteLine($"ERROR:\n\n{isEx.Message}");
                return null;
            }

            return image;
        }

With the current code this is the output when I print an image: https://imgur.com/a/wW4be9x
It just prints out random gibberish. Is there a way to fix this?

标签： c#printingxamarin.android