Python tkinter event advanced usage instance, pythontkinter

Python tkinter event advanced usage instance, pythontkinter

This example describes the advanced usage of Python tkinter events. We will share this with you for your reference. The details are as follows:

Let's take a look at the running effect:

Complete instance code:

# -*- coding:utf-8-*-#! python3from tkinter import *import threading, timetrace = 0class CanvasEventsDemo:  def __init__(self, parent=None):    canvas = Canvas(width=300, height=300, bg='beige')    canvas.pack()    canvas.bind('<ButtonPress-1>', self.onStart)   # click    canvas.bind('<B1-Motion>',   self.onGrow)    # and drag    canvas.bind('<Double-1>',   self.onClear)   # delete all    canvas.bind('<ButtonPress-3>', 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 = eventclass CanvasEventsDemoTags(CanvasEventsDemo):  def __init__(self, parent=None):    CanvasEventsDemo.__init__(self, parent)    self.canvas.create_text(100, 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')      # 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()