/Demo/tkinter/matt/canvas-moving-w-mouse.py

 1from Tkinter import *
 2
 3# this file demonstrates the movement of a single canvas item under mouse control
 4
 5class Test(Frame):
 6    ###################################################################
 7    ###### Event callbacks for THE CANVAS (not the stuff drawn on it)
 8    ###################################################################
 9    def mouseDown(self, event):
10        # remember where the mouse went down
11        self.lastx = event.x
12        self.lasty = event.y
13
14    def mouseMove(self, event):
15        # whatever the mouse is over gets tagged as CURRENT for free by tk.
16        self.draw.move(CURRENT, event.x - self.lastx, event.y - self.lasty)
17        self.lastx = event.x
18        self.lasty = event.y
19
20    ###################################################################
21    ###### Event callbacks for canvas ITEMS (stuff drawn on the canvas)
22    ###################################################################
23    def mouseEnter(self, event):
24        # the CURRENT tag is applied to the object the cursor is over.
25        # this happens automatically.
26        self.draw.itemconfig(CURRENT, fill="red")
27
28    def mouseLeave(self, event):
29        # the CURRENT tag is applied to the object the cursor is over.
30        # this happens automatically.
31        self.draw.itemconfig(CURRENT, fill="blue")
32
33    def createWidgets(self):
34        self.QUIT = Button(self, text='QUIT', foreground='red',
35                           command=self.quit)
36        self.QUIT.pack(side=LEFT, fill=BOTH)
37        self.draw = Canvas(self, width="5i", height="5i")
38        self.draw.pack(side=LEFT)
39
40        fred = self.draw.create_oval(0, 0, 20, 20,
41                                     fill="green", tags="selected")
42
43        self.draw.tag_bind(fred, "<Any-Enter>", self.mouseEnter)
44        self.draw.tag_bind(fred, "<Any-Leave>", self.mouseLeave)
45
46        Widget.bind(self.draw, "<1>", self.mouseDown)
47        Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
48
49    def __init__(self, master=None):
50        Frame.__init__(self, master)
51        Pack.config(self)
52        self.createWidgets()
53
54test = Test()
55test.mainloop()