Demo/tkinter/matt/canvas-mult-item-sel.py

   1 from Tkinter import *
   2
   3 # allows moving dots with multiple selection.
   4
   5 SELECTED_COLOR = "red"
   6 UNSELECTED_COLOR = "blue"
   7
   8 class 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
  77 test = Test()
  78 test.mainloop()