from gpanel import *

import cmath

def cross(z,e=0.01):
    a = z.real
    b = z.imag
    line(a-e,b,a+e,b)
    line(a,b-e,a,b+e)
    
@onMouseClicked
def init(x,y):
    clear()
    # Koordinatensystem
    setColor("black");
    line(-4,0,4,0)
    line(0,-4,0,4)
    circle(0,0,1)

def myfunc(z):     
    return z*z
def mycircle(c,r=1.0, f=myfunc):
    for i in range(0,360):
        a = i/180.0*math.pi
        z = c+complex(math.cos(a),math.sin(a))*r
 #       z = c+complex(math.cos(a),math.sin(a))*r*(1+math.cos(a*20)*0.1)
#        b = (i % 90 - 45)/180.0*math.pi ;  z = c+complex(math.cos(a),math.sin(a))*r*math.sqrt(math.tan(b)**2+1)
        setColor("blue")
        cross(z)
        setColor("red")
        cross(f(z))
    

def show(z):
    init(0,0)
    setColor("black")
    cross(z)
    setColor("red")
    cross(myfunc(z))
    mycircle(z,1.0, myfunc)
    
@onMouseMoved
def mouseMoved(x,y):
    show(complex(x,y));

makeGPanel(-6, 6, -6, 6)
init(0,0)