def replacedynselection(self,newlightnames):

        """as a dynamic selection changes, keep calling this function with the

        names of the lights in the dynamic selection. the original selection (at the time

        of markfordynselection) will be shown along with any new lights"""

        self.selectedlights = self.origselection + [l for l in newlightnames if l not in self.origselection]

        self.updateselectionboxes()

    def select(self,lightname,select=1,dyn=0): # select=0 for deselect

        if select:

            if lightname not in self.selectedlights:

                self.selectedlights.append(lightname)

        elif lightname in self.selectedlights:

            self.selectedlights.remove(lightname)

        self.updateselectionboxes()

    #

    # LMB click or drag

    #

    def leftpress(self,ev):

        self.lmbstate='pressed'

        self.lmbstart=(ev.x,ev.y)

        shifted=ev.state & 1

        control=ev.state & 4

        touching=self.findoverlappinglights((ev.x-self.halo,ev.y-self.halo,ev.x+self.halo,ev.y+self.halo))

        istouching=len(touching)>0

        if not istouching:

            # clicked in space

            if not shifted and not control and len(self.selectedlights)>0:

                # either a deselect (if no motion) or a level change (if motion)

                self.lmbstate = 'deselect-or-level'

            if shifted or control or len(self.selectedlights)==0:

                # with shift/control, add/subtract lights to selection

                self.lmbstate='rectangle'

        else:

            # clicked a selectable object

            # toggle selection

            if touching[0] in self.selectedlights:

                if shifted:

                    # deselect

                    self.select(touching[0],0)

                    # and do nothing else

                    self.lmbstate=None

                bboxes.append(self.bbox(o))

        return bboxes

    def findoverlappinglights(self,box,enclosed=0):

        "returns all the different name_ tags for lights that are within (or enclosed by) the box"

        lights=[]

        if enclosed:

            candidates = self.find_enclosed(*box)

        else:

            candidates = self.find_overlapping(*box)

        for o in candidates:

            for t in self.gettags(o):

                if t.startswith("name_"):

                    n = self.tagtoname(t[5:])

                    if n and (n not in lights):

                        lights.append(n)

        return lights

root=Tk()

root.wm_geometry("+376+330")

s=Stage(root)

s.setimage('guysanddolls.gif')

s.pack()

root.mainloop()