# Graphics/Ccurve.py
# C-curve page 52 
# Try: ccurve(100,100,50,0,12)  

from graphics import *
from math import *
import math

ANGLE = math.pi/4       # angle=45 in radians
startx,starty = 100,100
length = 200
def initGraphics():
    win = GraphWin( "Fractal C Curve", 400, 400  )
    return win

def ccurve (x,y,len,alpha,n):
        print " x= ",x," y= ",y," len= ",len," alpha= ",alpha," n= ", n
        if  n == 0 :
                x1= x
                y1= y
                x2= x + len * cos(alpha)
                y2= y + len * sin(alpha)
                print " x1= ",x," y1= ",y1," x2= ",x2," y2= ",y2
                linea = Line(Point(x1,y1),Point(x2,y2))
                linea.draw(win)
        else:
                len = len / sqrt(2)
                ccurve(x,y,len,alpha + ANGLE,n-1)
                x = x + len * cos(alpha + ANGLE)
                y = y + len * sin(alpha + ANGLE)
                ccurve(x,y,len,alpha-ANGLE,n-1)

def main():
        global win
        win = initGraphics()
        n=3  # n=12   
        ccurve(startx,starty,length,0,n)  
        message = Text( Point(150,375), "Click anywhere to stop!" )
        message.draw( win )
        win.getMouse()
        win.close()

main()