Python Tkinter Smooth Move

Question

I'm trying to move a canvas circle across a tkinter window. I'nm using canvas.move, but it just has the object reappear in the new location. I want to actually see it travel. Is there a way to do this? I have the following:

def move_to(self, user_id, old_location, new_location):
    self.user_list[user_id].set_location(new_location)
    user_canvas_id = self.user_id_dict[user_id]
    row_delta = new_location[ROW_INDEX] - old_location[ROW_INDEX]
    col_delta = new_location[COL_INDEX] - old_location[COL_INDEX]
    self.canvas.move(user_canvas_id, row_delta, col_delta)


def roaming_handler(self, user_id):
    row = randrange(1, self.number_of_events * 125)
    col = randrange(1, self.number_of_events * 125)
    user_location = self.user_list[user_id].get_location()
    self.move_to(user_id, user_location, (row, col))

There is also a variety of other things going on in the simulation at the time, and many of them will at one point or another call this.

Answer 1

I think this is what you are looking for:

You have to click on the circle and drag it to the new position

import tkinter

# Create some constants
RADIUS    = 50
START_POS = 10
TAG = 'circle'

# The dragging function
def drag_circle(event, canvas):
    r = RADIUS / 2
    x = canvas.canvasx(event.x)
    y = canvas.canvasy(event.y)
    canvas.coords(TAG, x - r, y - r, x + r, y + r)

# Create window and canvas
root = tkinter.Tk()
canvas = tkinter.Canvas(root)
canvas.pack(fill=tkinter.BOTH, expand=True)

# Draw a circle
canvas.create_oval(
    START_POS, START_POS, START_POS + RADIUS, START_POS + RADIUS,
    fill='#555', width=0, tags=TAG)

# Bind function to event
canvas.tag_bind(TAG, '<B1-Motion>', lambda e: drag_circle(e, canvas))

# Run mainloop
root.mainloop()

Answer 2

I think you simply need to add a delay to the process, so you can " see it travel " as you said. This is how you do it:

canvas.update()
canvas.after(#number of miliseconds)

example code:

import tkinter

canvas = tkinter.Canvas(width=600, height=200)
canvas.pack()

canvas.create_oval(250, 50, 350, 100)

for x in range(100):
    canvas.move(1, -5, 0)
    canvas.update()
    canvas.after(100)