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Find the cursor's current position in Python turtle

How can I find the current mouse position in Python that can be integrated into turtle? I would prefer if you did not use any non-builtin modules (downloadable modules) Any answers would be appreciated

like image 367
ndurvasula Avatar asked Dec 23 '13 15:12

ndurvasula


1 Answers

We can reach down into turtle's Tk underpinnings to enable the '<Motion>' event. I cast the function to set/unset the event to look like a method of the turtle screen but you can call it on the singular screen instance turtle.Screen():

import turtle

def onmove(self, fun, add=None):
    """
    Bind fun to mouse-motion event on screen.

    Arguments:
    self -- the singular screen instance
    fun  -- a function with two arguments, the coordinates
        of the mouse cursor on the canvas.

    Example:

    >>> onmove(turtle.Screen(), lambda x, y: print(x, y))
    >>> # Subsequently moving the cursor on the screen will
    >>> # print the cursor position to the console
    >>> screen.onmove(None)
    """

    if fun is None:
        self.cv.unbind('<Motion>')
    else:
        def eventfun(event):
            fun(self.cv.canvasx(event.x) / self.xscale, -self.cv.canvasy(event.y) / self.yscale)
        self.cv.bind('<Motion>', eventfun, add)

def goto_handler(x, y):
    onmove(turtle.Screen(), None)  # avoid overlapping events
    turtle.setheading(turtle.towards(x, y))
    turtle.goto(x, y)
    onmove(turtle.Screen(), goto_handler)

turtle.shape('turtle')

onmove(turtle.Screen(), goto_handler)

turtle.mainloop()

My code includes an example motion event handler that makes the turtle follow the cursor like a cat chasing a laser pointer. No clicks necessary (except for the initial click to make the window active.):

enter image description here

like image 104
cdlane Avatar answered Sep 19 '22 04:09

cdlane