self.subnames = subnames

        self.refresh()

    def refresh(self):

        # reload subs from disk

        self.submasters = Submasters()

        self.all_subs = circcycle(self.subnames)

        self.current_sub = self.submasters.get_sub_by_name(self.all_subs.next())

        self.current_level = 1.0

        self.kept_levels = {} # subname : level [0..1]

        self.keep_solo_mode = 'keep' # either 'keep' or 'solo'

    def clear_kept_levels(self):

        self.kept_levels.clear()

    def next(self):

        if self.keep_solo_mode == 'keep':

            self.kept_levels[self.current_sub] = self.current_level

        self.current_sub = self.submasters.get_sub_by_name(self.all_subs.next())

    def prev(self):

        if self.keep_solo_mode == 'keep':

            self.kept_levels[self.current_sub] = self.current_level

        self.current_sub = self.submasters.get_sub_by_name(self.all_subs.prev())

    def toggle_keep_mode(self):

        if self.keep_solo_mode == 'keep':

            self.keep_solo_mode = 'solo'

        else:

            self.keep_solo_mode = 'keep'

    def get_levels_as_sub(self):

        if self.keep_solo_mode == 'keep':

            # send all levels in self.kept_levels

            levelsub = combine_subdict(self.kept_levels)

        else:

            levelsub = self.current_sub * self.current_level

        return levelsub

class TkGyro(Tk.Canvas, AbstractSimpleController):

    def __init__(self, master, subnames):

        Tk.Canvas.__init__(self, master, bg='black', bd=0, highlightthickness=0,

            confine=None)

        AbstractSimpleController.__init__(self, subnames)

        height = int(self.winfo_screenheight())

        width = int(self.winfo_screenwidth())

        self.left = self.create_rectangle((0, 0, width / 2, height),

            tags='left', fill='black')

        self.right = self.create_rectangle((width / 2, 0, width, height),

            tags='right', fill='black')