#Sierpinski Gasket hip-pocket program in Python/Tkinter
#William Baker, Summer 2004, illiMath04 Program
#Adapted from Math198 course notes by Prof. George Francis
#University of Illinois Urbana-Champaign Dept. of Mathematics


import Tkinter
import math
import time
import random

defaldelay=0 #default delay time
defalstep=4000 #default number of steps per click

#function to create a point
#point is created by drawing a line one pixel in length
#Parameters: current Canvas, x coordinate, y coordinate
def createPoint(canvas, x0, y0):
   canvas.create_line(x0, y0, x0+1, y0, fill="red")

#startAnimation()
#This function acutal draws the gasket, it is called when
#the start button is pressed
def startAnimation():
   x=400 #starting point
   y=200
   xList=[100,500,500] #x and y coordinates of gasket corners
   yList=[264,100,326]

   #iterate for the specified number of times, each time
   #adding a point
   for j in range(0, int(numsteps.get())): 
      i=randclass.randint(0,2)

      x=(x+xList[i])/2.0
      y=(y+yList[i])/2.0

      createPoint(canvas,x,y)      
     
      canvas.update()
      #delay drawing based on animation delay specified
      time.sleep(int(timedelay.get())/20.0)


#clear()
#clears the canvas so that another gasket may be drawn
def clear():
    canvas.delete("all")


window = Tkinter.Tk()
window.title("Sierpinski Gasket in Python/Tkinter")

#below define the labels, buttons, and input fields
clear_button = Tkinter.Button(window, text = "Clear", command = clear)

start = Tkinter.Button(window, text="Start", command=startAnimation)
delLabel=Tkinter.Label(window, width="15")
delLabel.configure(text="Time Delay= ")
timedelay=Tkinter.StringVar()
timedelay.set(`defaldelay`)
numsteps=Tkinter.StringVar()
numsteps.set(`defalstep`)
delentry = Tkinter.Entry(window, width="15", textvariable=timedelay)
stepLabel=Tkinter.Label(window, width="15")
stepLabel.configure(text="Num Points= ")
stepentry=Tkinter.Entry(window, width="15", textvariable=numsteps)
canvas = Tkinter.Canvas(window, width=640, height=480)
randclass=random.Random()

canvas.pack(side="top")
delLabel.pack(side="left")
delentry.pack(side="left")
start.pack(side="right")
clear_button.pack(side = "right")
stepLabel.pack(side="left")
stepentry.pack(side="left")

# start event loop
window.mainloop()