def __init__(self, parent, channelnum):

        """channelnum is 1..68, like the real dmx"""

        tk.Frame.__init__(self,parent)

        self.channelnum=channelnum

        self.currentlevel=0 # the level we're displaying, 0..1

        # 3 widgets, left-to-right:

        # channel number -- will turn yellow when being altered

        self.num_lab = tk.Label(self, text=str(channelnum),

                                width=3, bg='grey40', 

                                fg='white', font=stdfont,

                                padx=0, pady=0, bd=0, height=1)

        self.num_lab.pack(side='left')

        # text description of channel

        self.desc_lab=tk.Label(self, text=Patch.get_channel_name(channelnum),

                               width=14, font=stdfont,

                               anchor='w',

                               padx=0, pady=0, bd=0, 

                 height=1, bg='black', fg='white')

        self.desc_lab.pack(side='left')

        # current level of channel, shows intensity with color

        self.level_lab = tk.Label(self, width=3, bg='lightBlue',

                                  font=stdfont,

                                  anchor='e', 

                                  padx=1, pady=0, bd=0, height=1)

        self.level_lab.pack(side='left')

        self.setlevel(0)

        self.setupmousebindings()

    def setupmousebindings(self):

        def b1down(ev):

            self.desc_lab.config(bg='cyan')

            self._start_y=ev.y

            self._start_lev=self.currentlevel

        def b1motion(ev):

            delta=self._start_y-ev.y

            self.changelevel(self._start_lev+delta*.005)

        def b1up(ev):

            self.desc_lab.config(bg='black')

        def b3up(ev):

            self.changelevel(0.0)

        def b3down(ev):

            self.changelevel(1.0)

        # make the buttons work in the child windows

        for w in self.winfo_children():

            for e,func in (('<ButtonPress-1>',b1down),

                           ('<B1-Motion>',b1motion),

                           ('<ButtonRelease-1>',b1up),

                           ('<ButtonRelease-3>', b3up),

                           ('<ButtonPress-3>', b3down)):

                w.bind(e,func)

#                w.bind(e,lambda ev,e=e: eventtoparent(ev,e))

    def colorlabel(self):

        """color the level label based on its own text (which is 0..100)"""

        txt=self.level_lab['text'] or "0"

        lev=float(txt)/100

        self.level_lab.config(bg=gradient(lev))

    def setlevel(self,newlev):

        """the main program is telling us to change our

        display. newlev is 0..1"""

        self.currentlevel=newlev

        newlev="%d"%(newlev*100)

        olddisplay=self.level_lab.cget('text')

        if newlev!=olddisplay:

            self.level_lab.config(text=newlev)

            self.colorlabel()

    def getlevel(self):

        """returns currently displayed level, 0..1"""

        return self.currentlevel

    def changelevel(self,newlev):

        """the user is adjusting the level on this widget.  the main

        program needs to hear about it. then the main program will

        call setlevel()"""

        dispatcher.send("levelchanged",channel=self.channelnum,newlevel=newlev)

class Levelbox(tk.Frame):

    def __init__(self, parent, num_channels=68):

        tk.Frame.__init__(self,parent)

        global stdfont

        stdfont = tkFont.Font(size=9)

        self.levels = [] # Onelevel objects

        frames = (make_frame(self), make_frame(self))

        for channel in range(1, num_channels+1):

            # frame for this channel

            f = Onelevel(frames[channel > (num_channels/2)],channel)

            self.levels.append(f)

            f.pack(side='top')

        #dispatcher.connect(setalevel,"setlevel")