Python Forum

from tkinter import *
import turtle
from math import cos,sin,tan,pi

root = Tk()

def graph ():
  pen.penup()
  angle = 0
  theta = 0.01
  steps = int ((100*pi/theta)+1)
  def stop():
    stop_button=Button(root, text="Stop")
    stop_button.grid(row=0,column=2,padx=5,pady=5)

  for t in range(0,steps):
    a = 1
    b = 5
    c = 6
      
    angle+=theta
    x=(cos(a*angle)+cos(b*angle)+cos(c*angle))*100
    y=(sin(a*angle)+sin(b*angle)+sin(c*angle))*100
    
    pen.goto(x,y)
    pen.pendown()
    if stop_button == True:
      break

canvas=turtle.Canvas(master=root, width=650, height=650)
canvas.grid(row=0, column=0)

pen=turtle.RawTurtle(canvas)

graph_button=Button(root, text="Graph", command=graph)
graph_button.grid(row=0,column=1,padx=5,pady=5)

stop_button=Button(root, text="Stop")
stop_button.grid(row=0,column=2,padx=5,pady=5)

root.mainloop()

I need help with this function.
how can I make a tkinter Button that stop/break a for loop in a function that draws with turtle?

Here's a way to stop the graph using the graph button.

graphing = False

def graph ():
    global graphing

    if graphing:
        graphing = False
    else:
        graphing = True
        pen.penup()
        angle = 0
        theta = 0.01
        steps = int ((100*pi/theta)+1)
        stop_plot = False

        for t in range(0,steps):
            a = 1
            b = 5
            c = 6

            angle+=theta
            x=(cos(a*angle)+cos(b*angle)+cos(c*angle))*100
            y=(sin(a*angle)+sin(b*angle)+sin(c*angle))*100

            pen.goto(x,y)
            pen.pendown()
            if not graphing:
                break
    graphing = False

The "graphing" variable is used to remember state; True while graphing, otherwise False. If you call graph while graphing == False, the pen begins drawing the graph. If you press the graph button again before the graph completes, graphing is set to False which ends the graph loop.

If you really want a stop button the thing you need to do is make a global variable and set the value when you press the stop button. The important thing is the variable must be accessible by both the graph function and whatever function you call when the stop button is pressed.