1from Tkinter import *
2
3# allows moving dots with multiple selection.
4
5SELECTED_COLOR = "red"
6UNSELECTED_COLOR = "blue"
7
8class Test(Frame):
9    ###################################################################
10    ###### Event callbacks for THE CANVAS (not the stuff drawn on it)
11    ###################################################################
12    def mouseDown(self, event):
13        # see if we're inside a dot. If we are, it
14        # gets tagged as CURRENT for free by tk.
15
16        if not event.widget.find_withtag(CURRENT):
17            # we clicked outside of all dots on the canvas. unselect all.
18
19            # re-color everything back to an unselected color
20            self.draw.itemconfig("selected", fill=UNSELECTED_COLOR)
21            # unselect everything
22            self.draw.dtag("selected")
23        else:
24            # mark as "selected" the thing the cursor is under
25            self.draw.addtag("selected", "withtag", CURRENT)
26            # color it as selected
27            self.draw.itemconfig("selected", fill=SELECTED_COLOR)
28
29        self.lastx = event.x
30        self.lasty = event.y
31
32
33    def mouseMove(self, event):
34        self.draw.move("selected", event.x - self.lastx, event.y - self.lasty)
35        self.lastx = event.x
36        self.lasty = event.y
37
38    def makeNewDot(self):
39        # create a dot, and mark it as current
40        fred = self.draw.create_oval(0, 0, 20, 20,
41                                     fill=SELECTED_COLOR, tags=CURRENT)
42        # and make it selected
43        self.draw.addtag("selected", "withtag", CURRENT)
44
45    def createWidgets(self):
46        self.QUIT = Button(self, text='QUIT', foreground='red',
47                           command=self.quit)
48
49        ################
50        # make the canvas and bind some behavior to it
51        ################
52        self.draw = Canvas(self, width="5i", height="5i")
53        Widget.bind(self.draw, "<1>", self.mouseDown)
54        Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
55
56        # and other things.....
57        self.button = Button(self, text="make a new dot", foreground="blue",
58                             command=self.makeNewDot)
59
60        message = ("%s dots are selected and can be dragged.\n"
61                   "%s are not selected.\n"
62                   "Click in a dot to select it.\n"
63                   "Click on empty space to deselect all dots."
64                   ) % (SELECTED_COLOR, UNSELECTED_COLOR)
65        self.label = Message(self, width="5i", text=message)
66
67        self.QUIT.pack(side=BOTTOM, fill=BOTH)
68        self.label.pack(side=BOTTOM, fill=X, expand=1)
69        self.button.pack(side=BOTTOM, fill=X)
70        self.draw.pack(side=LEFT)
71
72    def __init__(self, master=None):
73        Frame.__init__(self, master)
74        Pack.config(self)
75        self.createWidgets()
76
77test = Test()
78test.mainloop()
79