Соединение двух точек кривой, Построение дуги эллипса под углом

from Tkinter import *
from math import *
 
def makeModel(event):
    x1=int(e1.get())
    y1=int(e2.get())
    x2=int(e3.get())
    y2=int(e4.get())
 
    array = [ ]
    x = x1
    
    a = (sqrt((x2-x1)**2 + (y2-y1)**2))/2
    b = a
    print a
    print b
 
    while x != x2: 
        y = (b / a) * (sqrt(abs(a**2 - x**2)))
        #print y
        array.append(x)
        array.append(y)
        x += .5
    print array
 
    canv.create_rectangle(x1 - 3, y1 - 3, x1 + 3, y1 + 3, fill='red', outline = 'red')
    canv.create_rectangle(x2 - 3, y2 - 3, x2 + 3, y2 + 3, fill='red', outline = 'red')
    ln = canv.create_line(array, width = 1, fill = 'green')
    
################################### Interface ##################################
root = Tk()
root.title("Mouse movement model")
 
lb1 = Label(root, width = 17, text = 'Enter the coordinates:')
lb2 = Label(root, width = 3, text = 'x1 =')
lb3 = Label(root, width = 3, text = 'y1 =')
lb4 = Label(root, width = 3, text = 'x2 =')
lb5 = Label(root, width = 3, text = 'y2 =')
 
canv = Canvas(width = 640, height = 480, bg = 'white')
 
but = Button(root, width = 15, text = "Make Model")
but.bind('<Button-1>', makeModel)
 
e1 = Entry(root, width = 5)
e2 = Entry(root, width = 5)
e3 = Entry(root, width = 5)
e4 = Entry(root, width = 5)
 
lb1.grid(row = 1, column = 1)
lb2.grid(row = 1, column = 2)
e1.grid(row = 1, column = 3)
lb3.grid(row = 1, column = 4)
e2.grid(row = 1, column = 5)
lb4.grid(row = 1, column = 6)
e3.grid(row = 1, column = 7)
lb5.grid(row = 1, column = 8)
e4.grid(row = 1, column = 9)
but.grid(row = 1, column = 10, pady = 5, padx = 3)
canv.grid(row = 2, column = 1, columnspan = 10)
 
mainloop()