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, tags=CURRENT)
# and make it selected
self.draw.addtag("selected", "withtag", CURRENT)
def createWidgets(self):
self.QUIT = Button(self, text='QUIT', foreground='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", foreground="blue",
command=self.makeNewDot)
message = ("%s dots are selected and can be dragged.\n"
"%s are not selected.\n"
"Click in a dot to select it.\n"
"Click on empty space to deselect all dots."
) % (SELECTED_COLOR, UNSELECTED_COLOR)
self.label = Message(self, width="5i", text=message)
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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