def get_final_window_rect(self):
        """Gets the final size of the main window of guake. The height
        is the window_height property, width is window_width and the
        horizontal alignment is given by window_alignment.
        """
        screen = self.window.get_screen()
        height = self.client.get_int(KEY('/general/window_height'))
        width = 30
        halignment = self.client.get_int(KEY('/general/window_halignment'))

        # get the rectangle just from the first/default monitor in the
        # future we might create a field to select which monitor you
        # wanna use
        window_rect = screen.get_monitor_geometry(0)
        total_width = window_rect.width
        window_rect.height = window_rect.height * height / 100
        window_rect.width = window_rect.width * width / 100

        if width < total_width:
            if halignment == ALIGN_LEFT:
                window_rect.x = (total_width - window_rect.width) / 2
            elif halignment == ALIGN_LEFT:
                window_rect.x = 0
            elif halignment == ALIGN_RIGHT:
                window_rect.x = total_width - window_rect.width
        window_rect.y = 0
        return window_rect