Demo/tkinter/matt/canvas-moving-or-creating.py

   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
  14         if not event.widget.find_withtag("current"):
  15             # there is no dot here, so we can make one,
  16             # and bind some interesting behavior to it.
  17             # ------
  18
  19             # create a dot, and mark it as current
  20             fred = self.draw.create_oval(event.x - 10, event.y -10, event.x +10, event.y + 10,
  21                                          {"fill" : "green", "tag" : "current"})
  22
  23             self.draw.bind(fred, "<Any-Enter>", self.mouseEnter)
  24             self.draw.bind(fred, "<Any-Leave>", self.mouseLeave)
  25
  26         self.lastx = event.x
  27         self.lasty = event.y
  28
  29
  30     def mouseMove(self, event):
  31         self.draw.move("current", event.x - self.lastx, event.y - self.lasty)
  32         self.lastx = event.x
  33         self.lasty = event.y
  34
  35     ###################################################################
  36     ###### Event callbacks for canvas ITEMS (stuff drawn on the canvas)
  37     ###################################################################
  38     def mouseEnter(self, event):
  39         # the "current" tag is applied to the object the cursor is over.
  40         # this happens automatically.
  41         self.draw.itemconfig("current", {"fill" : "red"})
  42
  43     def mouseLeave(self, event):
  44         # the "current" tag is applied to the object the cursor is over.
  45         # this happens automatically.
  46         self.draw.itemconfig("current", {"fill" : "blue"})
  47
  48
  49     def createWidgets(self):
  50         self.QUIT = Button(self, {'text': 'QUIT',
  51                                   'fg': 'red',
  52                                   'command': self.quit})
  53         self.QUIT.pack({'side': 'left', 'fill': 'both'})
  54         self.draw = Canvas(self, {"width" : "5i", "height" : "5i"})
  55         self.draw.pack({'side': 'left'})
  56
  57
  58         Widget.bind(self.draw, "<1>", self.mouseDown)
  59         Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
  60
  61     def __init__(self, master=None):
  62         Frame.__init__(self, master)
  63         Pack.config(self)
  64         self.createWidgets()
  65
  66 test = Test()
  67 test.mainloop()
  68
  69
  70