Tkinter coords

[dan789]

Hi, I want to move my object (image) in tkinter, but it doesn´t work. This is what I have so far:

class Playfield:
...
def build_playfield(self):
...
self.field_icon_player = tkinter.PhotoImage(file="player.png")
...
self.canvas.create_image(j*50, i*50, anchor=NW, image=self.field_icon_player)
...

        for i in range(100):
            self.canvas.coords(self.field_icon_player, 10, 10)

How can I move with this object? Coords doesn´t work in this case. Am I doing something wrong with implementing this inside a class? Thanks.

[wuf]

Hi dan789

Try following:

self.canvas.move(self.field_icon_player, 10, 10)

wuf :-)

[Larz60+]

You can also move using coords, wuf's solution is better

.coords(tagOrId, x0, y0, x1, y1, ..., xn, yn)

If you pass only the tagOrId argument, returns a tuple of the coordinates of the lowest or only object specified by that argument. The number of coordinates depends on the type of object. In most cases it will be a 4-tuple (x1, y1, x2, y2) describing the bounding box of the object.

You can move an object by passing in new coordinates.

[deanhystad]

This is not correct:

self.canvas.move(self.field_icon_player, 10, 10)

field_icon_player is the PhotoImage object, not a canvas image object. You need the id returned when you create the canvas image.

self.field_icon_player = self.canvas.create_image(j*50, i*50, anchor=NW, image=tkinter.PhotoImage(file="player.png"))
...
 
        for i in range(100):
            self.canvas.move(self.field_icon_player, 10, 10)

This will move the image along the xy diagonal 1000 pixels. You will only see the image at the end of the move. The window will not get updated to show any of the between moves because you are blocking the mainloop. This can be seen in the example below:

import tkinter as tk
from time import sleep

root = tk.Tk()
canvas = tk.Canvas(root, width=500, height=500)
canvas.pack()
dot = canvas.create_oval([0, 0, 20, 20], fill="red")
root.update()
for _ in range(10):
    canvas.move(dot, 10, 10)
    sleep(0.25)
root.mainloop()

One solution is update the canvas each time you move the image.

import tkinter as tk
from time import sleep

root = tk.Tk()
canvas = tk.Canvas(root, width=500, height=500)
canvas.pack()
dot = canvas.create_oval([0, 0, 20, 20], fill="red")
root.update()
for _ in range(10):
    canvas.move(dot, 10, 10)
    canvas.update()
    sleep(0.25)
root.mainloop()

A better solution is to periodically call the move function.

import tkinter as tk

def move_thing(thing, dx, dy, count, delay=250):
    canvas.move(thing, dx, dy)
    count = count - 1
    if count > 0:
        canvas.after(delay, move_thing, thing, dx, dy, count, delay)

root = tk.Tk()
canvas = tk.Canvas(root, width=500, height=500)
canvas.pack()
dot = canvas.create_oval([0, 0, 20, 20], fill="red")
move_thing(dot, 1, 1, 500, 10)
root.mainloop()