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

   1 from Tkinter import *
   2
   3 # this file demonstrates the movement of a single canvas item under mouse control
   4
   5 class 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
  54 test = Test()
  55 test.mainloop()