def save_rib(self, file_name, bg=0, resolution=None, resfactor=1.0):
        """Save scene to a RenderMan RIB file.

        Keyword Arguments:

        file_name -- File name to save to.

        bg -- Optional background option.  If 0 then no background is
        saved.  If non-None then a background is saved.  If left alone
        (defaults to None) it will result in a pop-up window asking
        for yes/no.

        resolution -- Specify the resolution of the generated image in
        the form of a tuple (nx, ny).

        resfactor -- The resolution factor which scales the resolution.
        """
        if resolution is None:
            # get present window size
            Nx, Ny = self.render_window.size
        else:
            try:
                Nx, Ny = resolution
            except __HOLE__:
                raise TypeError(
                    "Resolution (%s) should be a sequence with two elements"%resolution
                )

        if len(file_name) == 0:
            return

        f_pref = os.path.splitext(file_name)[0]
        ex = tvtk.RIBExporter()
        ex.size = int(resfactor*Nx), int(resfactor*Ny)
        ex.file_prefix = f_pref
        ex.texture_prefix = f_pref + "_tex"
        self._lift()
        ex.render_window = self._renwin
        ex.background = bg

        if VTK_VER[:3] in ['4.2', '4.4']:
            # The vtkRIBExporter is broken in respect to VTK light
            # types.  Therefore we need to convert all lights into
            # scene lights before the save and later convert them
            # back.

            ########################################
            # Internal functions
            def x3to4(x):
                # convert 3-vector to 4-vector (w=1 -> point in space)
                return (x[0], x[1], x[2], 1.0 )
            def x4to3(x):
                # convert 4-vector to 3-vector
                return (x[0], x[1], x[2])

            def cameralight_transform(light, xform, light_type):
                # transform light by 4x4 matrix xform
                origin = x3to4(light.position)
                focus = x3to4(light.focal_point)
                neworigin = xform.multiply_point(origin)
                newfocus = xform.multiply_point(focus)
                light.position = x4to3(neworigin)
                light.focal_point = x4to3(newfocus)
                light.light_type = light_type
            ########################################

            save_lights_type=[]
            for light in self.light_manager.lights:
                save_lights_type.append(light.source.light_type)

            # Convert lights to scene lights.
            cam = self.camera
            xform = tvtk.Matrix4x4()
            xform.deep_copy(cam.camera_light_transform_matrix)
            for light in self.light_manager.lights:
                cameralight_transform(light.source, xform, "scene_light")

            # Write the RIB file.
            self._exporter_write(ex)

            # Now re-convert lights to camera lights.
            xform.invert()
            for i,light in enumerate(self.light_manager.lights):
                cameralight_transform(light.source, xform, save_lights_type[i])

            # Change the camera position. Otherwise VTK would render
            # one broken frame after the export.
            cam.roll(0.5)
            cam.roll(-0.5)
        else:
            self._exporter_write(ex)
dataset/ETHPy150Open enthought/mayavi/tvtk/pyface/tvtk_scene.py/TVTKScene.save_rib