Move what you drew on a canvas，drewcanvas,from Tkinter

Move what you drew on a canvas，drewcanvas,from Tkinter

from Tkinter import *import timetrace = 0 class CanvasEventsDemo:     def __init__(self, parent=None):        canvas = Canvas(width=300, height=300, bg='beige')         canvas.pack()        canvas.bind('<ButtonPress-1>', self.onStart)              canvas.bind('<B1-Motion>',     self.onGrow)               canvas.bind('<Double-1>',      self.onClear)              canvas.bind('<ButtonPress-3>', self.onMove)               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]              self.start = event        self.drawn = None    def onGrow(self, event):                             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')                   def onMove(self, event):        if self.drawn:                                       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 = eventclass 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('<KeyPress-o>', self.onMoveOvals)            self.canvas.master.bind('<KeyPress-r>', 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')              def onMoveRectangles(self, event):        print 'moving rectangles'        self.moveInSquares(tag='rectangles')    def moveInSquares(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)                self.canvas.update()                             time.sleep(0.25)                 if __name__ == '__main__':    CanvasEventsDemoTags()    mainloop()