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from Tkinter import *
# allows moving dots with multiple selection.
SELECTED_COLOR = "red"
UNSELECTED_COLOR = "blue"
class Test(Frame):
###################################################################
###### Event callbacks for THE CANVAS (not the stuff drawn on it)
###################################################################
def mouseDown(self, event):
# see if we're inside a dot. If we are, it
# gets tagged as "current" for free by tk.
if not event.widget.find_withtag("current"):
# we clicked outside of all dots on the canvas. unselect all.
# re-color everything back to an unselected color
self.draw.itemconfig("selected", {"fill" : UNSELECTED_COLOR})
# unselect everything
self.draw.dtag("selected")
else:
# mark as "selected" the thing the cursor is under
self.draw.addtag("selected", "withtag", "current")
# color it as selected
self.draw.itemconfig("selected", {"fill": SELECTED_COLOR})
self.lastx = event.x
self.lasty = event.y
def mouseMove(self, event):
self.draw.move("selected", event.x - self.lastx, event.y - self.lasty)
self.lastx = event.x
self.lasty = event.y
def makeNewDot(self):
# create a dot, and mark it as current
fred = self.draw.create_oval(0, 0, 20, 20,
{"fill" : SELECTED_COLOR, "tag" : "current"})
# and make it selected
self.draw.addtag("selected", "withtag", "current")
def createWidgets(self):
self.QUIT = Button(self, {'text': 'QUIT',
'fg': 'red',
'command': self.quit})
################
# make the canvas and bind some behavior to it
################
self.draw = Canvas(self, {"width" : "5i", "height" : "5i"})
Widget.bind(self.draw, "<1>", self.mouseDown)
Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
# and other things.....
self.button = Button(self, {"text" : "make a new dot",
"command" : self.makeNewDot,
"fg" : "blue"})
self.label = Message(self,
{"width" : "5i",
"text" : SELECTED_COLOR + " dots are selected and can be dragged.\n" +
UNSELECTED_COLOR + " are not selected.\n" +
"Click in a dot to select it.\n" +
"Click on empty space to deselect all dots." })
self.QUIT.pack({'side': 'bottom', 'fill': 'both'})
self.label.pack({"side" : "bottom", "fill" : "x", "expand" : 1})
self.button.pack({"side" : "bottom", "fill" : "x"})
self.draw.pack({'side': 'left'})
def __init__(self, master=None):
Frame.__init__(self, master)
Pack.config(self)
self.createWidgets()
test = Test()
test.mainloop()
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