1 from Tkinter import *

     2 

     3 # this file demonstrates a more sophisticated movement --

     4 # move dots or create new ones if you click outside the dots

     5 

     6 class Test(Frame):

     7     ###################################################################

     8     ###### Event callbacks for THE CANVAS (not the stuff drawn on it)

     9     ###################################################################

    10     def mouseDown(self, event):

    11         # see if we're inside a dot. If we are, it

    12         # gets tagged as CURRENT for free by tk.

    13         if not event.widget.find_withtag(CURRENT):

    14             # there is no dot here, so we can make one,

    15             # and bind some interesting behavior to it.

    16             # ------

    17             # create a dot, and mark it as CURRENT

    18             fred = self.draw.create_oval(

    19                 event.x - 10, event.y -10, event.x +10, event.y + 10,

    20                 fill="green", tags=CURRENT)

    21 

    22             self.draw.tag_bind(fred, "<Any-Enter>", self.mouseEnter)

    23             self.draw.tag_bind(fred, "<Any-Leave>", self.mouseLeave)

    24 

    25         self.lastx = event.x

    26         self.lasty = event.y

    27 

    28     def mouseMove(self, event):

    29         self.draw.move(CURRENT, event.x - self.lastx, event.y - self.lasty)

    30         self.lastx = event.x

    31         self.lasty = event.y

    32 

    33     ###################################################################

    34     ###### Event callbacks for canvas ITEMS (stuff drawn on the canvas)

    35     ###################################################################

    36     def mouseEnter(self, event):

    37         # the CURRENT tag is applied to the object the cursor is over.

    38         # this happens automatically.

    39         self.draw.itemconfig(CURRENT, fill="red")

    40 

    41     def mouseLeave(self, event):

    42         # the CURRENT tag is applied to the object the cursor is over.

    43         # this happens automatically.

    44         self.draw.itemconfig(CURRENT, fill="blue")

    45 

    46     def createWidgets(self):

    47         self.QUIT = Button(self, text='QUIT', foreground='red',

    48                            command=self.quit)

    49         self.QUIT.pack(side=LEFT, fill=BOTH)

    50         self.draw = Canvas(self, width="5i", height="5i")

    51         self.draw.pack(side=LEFT)

    52 

    53         Widget.bind(self.draw, "<1>", self.mouseDown)

    54         Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)

    55 

    56     def __init__(self, master=None):

    57         Frame.__init__(self, master)

    58         Pack.config(self)

    59         self.createWidgets()

    60 

    61 test = Test()

    62 test.mainloop()