from tkinter import *import threading, timetrace = 0 class CanvasEventsDemo:     def __init__(self, parent=None):        canvas = Canvas(width=300, height=300, bg='beige')         canvas.pack()        canvas.bind('
     
      ', self.onStart)      # click        canvas.bind('
      
       ',     self.onGrow)       # and drag        canvas.bind('
       
        ',      self.onClear)      # delete all        canvas.bind('
        
         ', self.onMove)       # move latest        self.canvas = canvas        self.drawn  = None        self.kinds = [canvas.create_oval, canvas.create_rectangle]            def onStart(self, event):        self.shape = self.kinds[0]        self.kinds = self.kinds[1:] + self.kinds[:1]      # start dragout        self.start = event        self.drawn = None            def onGrow(self, event):                              # delete and redraw        canvas = event.widget        if self.drawn: canvas.delete(self.drawn)        objectId = self.shape(self.start.x, self.start.y, event.x, event.y)        if trace: print(objectId)        self.drawn = objectId            def onClear(self, event):        event.widget.delete('all')                        # use tag all            def onMove(self, event):        if self.drawn:                                    # move to click spot            if trace: print(self.drawn)            canvas = event.widget            diffX, diffY = (event.x - self.start.x), (event.y - self.start.y)            canvas.move(self.drawn, diffX, diffY)            self.start = event    class CanvasEventsDemoTags(CanvasEventsDemo):    def __init__(self, parent=None):        CanvasEventsDemo.__init__(self, parent)        self.canvas.create_text(75, 8, text='Press o and r to move shapes')        self.canvas.master.bind('
         
          ', self.onMoveOvals)            self.canvas.master.bind('
          
           ', self.onMoveRectangles) self.kinds = self.create_oval_tagged, self.create_rectangle_tagged def create_oval_tagged(self, x1, y1, x2, y2): objectId = self.canvas.create_oval(x1, y1, x2, y2) self.canvas.itemconfig(objectId, tag='ovals', fill='blue') return objectId def create_rectangle_tagged(self, x1, y1, x2, y2): objectId = self.canvas.create_rectangle(x1, y1, x2, y2) self.canvas.itemconfig(objectId, tag='rectangles', fill='red') return objectId def onMoveOvals(self, event): print('moving ovals') self.moveInSquares(tag='ovals') # move all tagged ovals def onMoveRectangles(self, event): print('moving rectangles') self.moveInSquares(tag='rectangles') def moveInSquares(self, tag): # 5 reps of 4 times per sec for i in range(5): for (diffx, diffy) in [(+20, 0), (0, +20), (-20, 0), (0, -20)]: self.canvas.move(tag, diffx, diffy) self.canvas.update() # force screen redraw/update time.sleep(0.25) # pause, but don't block guiclass CanvasEventsDemoThread(CanvasEventsDemoTags): def moveEm(self, tag): for i in range(5): for (diffx, diffy) in [(+20, 0), (0, +20), (-20, 0), (0, -20)]: self.canvas.move(tag, diffx, diffy) time.sleep(0.25) # pause this thread only def moveInSquares(self, tag): threading.Thread(self.moveEm, (tag,)).start()if __name__ == '__main__': CanvasEventsDemoThread() mainloop()