类似于tkinter中pygame的get_rel（）的命令？

Question

我想知道当我将<Motion>事件绑定到函数时，如果在该函数中我可以使用pygame的mouse.get_rel()版本定义x和y变量，但在tkinter中。

Answer 1

事件的处理是不同的tkinter比pygame，所以不是直接mouse.get_rel()等同，它似乎更适合创造的东西，将每一个鼠标移动时（这是结合'<Motion>'事件完成）调用回调函数。为了帮助做到这一点，RelativeMotion类定义为隐藏和封装尽可能多的混乱细节。远远低于它运行的屏幕截图。

import tkinter as tk 

class RelativeMotion(object): 
    """ Relative mouse motion controller. """ 
    def __init__(self, callback): 
     self.__call__ = self._init_location # first call 
     self.callback = callback 

    def __call__(self, *args, **kwargs): 
     # Implicit invocations of special methods resolve to instance's type. 
     self.__call__(*args, **kwargs) # redirect call to instance itself 

    def _init_location(self, event): 
     self.x, self.y = event.x, event.y # initialize current position 
     self.__call__ = self._update_location # change for any subsequent calls 

    def _update_location(self, event): 
     dx, dy = event.x-self.x, event.y-self.y 
     self.x, self.y = event.x, event.y 
     self.callback(dx, dy) 

class Application(tk.Frame): # usage demo 
    def __init__(self, master=None): 
     tk.Frame.__init__(self, master) 
     self.grid() 
     self.createWidgets() 
     self.relative_motion = RelativeMotion(self.canvas_mouse_motion) 
     self.canvas.bind('<Motion>', self.relative_motion) # when over canvas 

    def createWidgets(self): 
     self.motion_str = tk.StringVar() 
     self.canvas_mouse_motion(0, 0) # initialize motion_str text 
     label_width = len(self.motion_str.get()) 
     self.motion_lbl = tk.Label(self, bg='white', width=label_width, 
            textvariable=self.motion_str) 
     self.motion_lbl.grid(row=0, column=0) 

     self.quit_btn = tk.Button(self, text='Quit', command=self.quit) 
     self.quit_btn.grid(row=1, column=0) 

     self.canvas = tk.Canvas(self, width='2i', height='2i', bg='white') 
     self.canvas.grid(row=1, column=1) 

    def canvas_mouse_motion(self, dx, dy): 
     self.motion_str.set('{:3d}, {:3d}'.format(dx, dy)) 

app = Application() 
app.master.title('Relative Motion Demo') 
app.mainloop() 

运行