public static void PrinterReceipt(Context context, String portname, RelativeLayout layout){

        String portName = portname; //ip address of your printer
        String portSettings = "";

        //have to measure the layout for it to print correctly, otherwise sizes are zero
        layout.measure(View.MeasureSpec.makeMeasureSpec(layout.getLayoutParams().width, View.MeasureSpec.EXACTLY),
                View.MeasureSpec.makeMeasureSpec(layout.getLayoutParams().height, View.MeasureSpec.EXACTLY));
        layout.layout(0, 0, layout.getMeasuredWidth(), layout.getMeasuredHeight());

        Bitmap bitmap = Bitmap.createBitmap(layout.getWidth(),layout.getHeight(), Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawColor(Color.WHITE);
        layout.draw(canvas);


        int maxWidth = 576; //default width of tsp100 receipt
        RasterDocument rasterDoc = new RasterDocument(RasterDocument.RasSpeed.Full, RasterDocument.RasPageEndMode.FeedAndFullCut, RasterDocument.RasPageEndMode.FeedAndFullCut, RasterDocument.RasTopMargin.Standard, 0, 0, 0);
        StarBitmap starbitmap = new StarBitmap(bitmap, false, maxWidth);

        StarIOPort port = null;
        try {
            /*
                       using StarIOPort3.1.jar (support USB Port)
                       Android OS Version: upper 2.2
             */
            port = StarIOPort.getPort(portName, portSettings, 10000, context);
            /*
                       using StarIOPort.jar
                       Android OS Version: under 2.1
                       port = StarIOPort.getPort(portName, portSettings, 10000);
             */

            try {
                Thread.sleep(500);
            }
            catch(InterruptedException e) {}

            byte[] command = rasterDoc.BeginDocumentCommandData();
            port.writePort(command, 0, command.length);
            command = starbitmap.getImageRasterDataForPrinting(true);
            port.writePort(command, 0, command.length);
            command = rasterDoc.EndDocumentCommandData();
            port.writePort(command, 0, command.length);

            try {
                Thread.sleep(1000);
            }
            catch(InterruptedException e) {
                e.printStackTrace();
            }
        } catch (StarIOPortException e) {
            ShowAlertMessage(context, "Failure", "Failed to connect to printer. " + e.getMessage());
        }
        finally {
            if(port != null) {
                try {
                    StarIOPort.releasePort(port);
                } catch (StarIOPortException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private static void ShowAlertMessage(final Context context, final String alertTitle, final String message){
        try {
            ((Activity)context).runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    AlertDialog.Builder dialog = new AlertDialog.Builder(context);
                    dialog.setNegativeButton("Ok", null);
                    AlertDialog alert = dialog.create();
                    alert.setTitle(alertTitle);
                    alert.setMessage(message);
                    alert.show();
                }});
        } catch (final Exception e) {
            Log.e("PrintReceipt", e.getMessage());
        }
    }