from tkinter import*
from turtle import*
def strelica():
    rt(30);bk(10);fd(10)
    lt(60);bk(10);fd(10)
    rt(30)
def broj():
    pu(); bk(20);write(i//25);fd(20);pd()
def koor_sustav():
    global i
    speed(6)
    setx(300);strelica();write('x');setx(-300);setx(0)
    lt(90);sety(300);strelica();write('y');sety(-300);sety(0)
    for i in range(-250,300,50):
        setx(i)
        fd(3);bk(6);broj();fd(3)
    setx(0);rt(90)
    for i in range(-250,300,50):
        if i!=0:
            sety(i)
            fd(3);bk(6);broj();fd(3)
def crtaj():
    pencolor('red')
    a=float(ua.get())
    b=float(ub.get())
    fx1=-10*a*25+b*25
    fx2=10*a*25+b*25
    pu();setpos(-10*25,fx1);pd();setpos(10*25,fx2)
koor_sustav()
p=Tk()
p.geometry('210x160')
t=Label(p,text='Graf linearne funkcije f(x)=ax+b')
t.place(x=20,y=10)
t1=Label(p,text='Parametar a:')
t1.place(x=10,y=40)
t2=Label(p,text='Parametar b:')
t2.place(x=10,y=70)
ua=Entry(p,width=8)
ua.place(x=90,y=40)
ub=Entry(p,width=8)
ub.place(x=90,y=70)
g=Button(p,text='Crtaj',width=6,command=crtaj)
g.place(x=90,y=100)