# Tk_linechart2.py

# Tk_linechart2.py

from Tkinter import *
from random import randint
import time

def yVal(val):
        return 550-5*val

class Cv(): 0
cv = Cv()
cv.s = 1
cv.x2 = 50
cv.demo = 50
cv.y2 = yVal(randint(0,100))

def step():
    if cv.s > 22:
        # new frame
        cv.s = 1
        cv.x2 = 50
        canvas.delete('temp') # only delete items tagged as temp
    x1 = cv.x2
    y1 = cv.y2
    cv.x2 = 50  + cv.s * 50
    r=1
    if cv.s % 2:
        r=-1
    cv.demo = max(min(cv.demo+(randint(10,50)*r),randint(70,100)),randint(0,30))
    cv.y2 = yVal(cv.demo)
    canvas.create_line(x1, y1, cv.x2, cv.y2, fill='red', tags='temp', width=3)
    # print(s, x1, y1, x2, y2)
    cv.s = cv.s+1
    canvas.after(200, step)

root = Tk()
root.title('simple line chart')

canvas = Canvas(root, width=1200, height=600, bg='white') # 0,0 is top left corner
canvas.pack(expand=YES, fill=BOTH)

Button(root, text='Quit', command=root.quit).pack()

canvas.create_line(50,550,1150,550, width=2) # x-axis
canvas.create_line(50,550,50,50, width=2)    # y-axis

# x-axis
for i in range(23):
    x = 50 + (i * 50)
    canvas.create_line(x,550,x,50, width=1, dash=(2,5))
    canvas.create_text(x,550, text='%d'% (10*i), anchor=N)

# y-axis
for i in range(11):
    y = 550 - (i * 50)
    canvas.create_line(50,y,1150,y, width=1, dash=(2,5))
    canvas.create_text(40,y, text='%d'% (10*i), anchor=E)

canvas.after(300, step)
root.mainloop()