background service shape

Im new to background services in android... i have managed to inflate an xml layout in a service like this

public class FloatingWindow extends Service{
WindowManager wm;
RelativeLayout ll;
LayoutInflater li;

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public void onCreate() {
    // TODO Auto-generated method stub
    super.onCreate();
    final View myview;
    li = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
    wm = (WindowManager) getSystemService(WINDOW_SERVICE);


    WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.TYPE_INPUT_METHOD |
            WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,// | WindowManager.LayoutParams.TYPE_SYSTEM_ALERT,
            WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
            PixelFormat.TRANSLUCENT);

    /////////////////////////Another params


    params = new WindowManager.LayoutParams(
       750,1250,
            WindowManager.LayoutParams.TYPE_PHONE,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSLUCENT);

    params.gravity = Gravity.CENTER | Gravity.CENTER;
    myview = li.inflate(R.layout.service_floating_window, null); // your layout here

    wm.addView(myview, params);
    params.x = 0;
    params.y = 0;

But thats just inflating an xml layout... Can i get the code for how to make a service with a different shape just like the image below... like a semi circle and not the regular activity shape(Rectangle) i know i shouldn't be jumping so fast to such complex things but i just want to learn quickly and looking at code and understanding is the best way... So can someone please tell me how to achieve this?