windows specific whole application opacity management

gistfile1.txt

    def _get_opacity(self):
        if platform == 'win':
            try:
                return winxpgui.GetLayeredWindowAttributes(HWND)[1] / 255.
            except Exception as e:
                Logger.error(
                    'failed to get opacity: {}'.format(e))

        else:
            Logger.warning(
                'window get opacity not implemented on {}'.format(platform))
        return 1

    def _set_opacity(self, value):
        if platform == 'win':
            win32gui.SetWindowLong(
                HWND, win32con.GWL_EXSTYLE,
                win32gui.GetWindowLong(
                    HWND, win32con.GWL_EXSTYLE) | win32con.WS_EX_LAYERED)
            winxpgui.SetLayeredWindowAttributes(
                HWND, win32api.RGB(0, 0, 0), max(1, int(value * 255)),
                win32con.LWA_ALPHA)

            return True
        else:
            Logger.error(
                'window set opacity not implemented on {}'.format(platform)
            )

    opacity = AliasProperty(_get_opacity, _set_opacity)

to get window handle (HWND)

    def _win_find_hwnd(self, *args):
        global HWND
        HWND = win32gui.FindWindow(None, NAME)
        Logger.debug('FindWindow returned {}'.format(HWND))
        if not HWND:
            Clock.schedule_once(self._win_find_hwnd, .01)