Interference of canvas items and problem in setting coordinates

Question

I'm working on an animation of a moving object, while drawing it's path. I want to draw the pixels in which the center of the object went through... but guess what? python decided to set the NW anchor of the image with the coordinates I send, instead of the center. I infer it has something to do with the pixels I draw simultaneously (creating a one pixel rectangle). so the image appear on the right of the path bellow... I want the center of it to be on the top of the pixels... adding the main of the code:

from tkinter import*
import time

dt = 0.01
clock_place = (500, 10)


def round_two(t, t0):
    return round((t-t0)*100)/100


def round_three(t, t0):
    return round((t-t0)*1000)/1000


# showing 'real time motion' for a known path (also cyclic), with
# parametric representation

def paint_known_path(x_pos, y_pos, t_0):
    window = Tk()
    canvas = Canvas(window, height=700, width=1000)
    canvas.pack()
    canvas.config(background='black')
    tennis_ball = PhotoImage(file='tennis ball.png')

    t = t_0
    x = x_pos(t_0)
    y = y_pos(t_0)
    particle = canvas.create_image(x, y, image=tennis_ball)
    clock = canvas.create_text(clock_place, text=round_two(t, t_0), 
    fill='white')
    while True:
        canvas.create_rectangle(x, y, x, y, outline='red')
        canvas.itemconfig(clock, text=round_two(t, t_0))
        t += dt
        x = x_pos(t)
        y = y_pos(t)
        canvas.moveto(particle, x, y)
        window.update()
        if x == x_pos(t_0) and y == y_pos(t_0):
            if t - t_0 > 100*dt:
                break
        time.sleep(dt)

    canvas.create_text((500, 100), text='orbit duration: ' + 
    str(round_three(t, t_0)), fill='white')
    window.mainloop()

Answer 1

It turns out to be quite a bit require, but here is the main completion components.

The first additional part that you need to add:

# print('the ten ball height', tennis_ball.height(), tennis_ball.width())
# tennis ball dimensions
tb_hght = tennis_ball.height()
tb_wdth = tennis_ball.width()
mid_point_x = x + tennis_ball.height() / 2
mid_point_y = y + tennis_ball.width() / 2

Secondly, also needed to add some functions to for x_pos and y_pos like this (these are just example functions to make the code work):

def x_pos(a):
    # any function of t,
    return 100

def y_pos(a):
    # any function of t,
    return 100

Furthermore, you need to call the function at the end like this:

paint_known_path(x_pos,y_pos,0)

Finally, need to add the mid_point_x and mid_point_y to the path that is drawn (as these will be the image centre points).