# Tk_mouse2rotate.py

# Tk_mouse2rotate.py

from Tkinter import *
import math
import time

root = Tk()
root.title("Tk mouse2rotate")
ww=200; hh=200

z = 0
spin = {}
while z < 1000:
    x = int(math.sin(math.radians(z))*1000.0)
    y = int(math.cos(math.radians(z))*1000.0)
    spin[z] = x,y
    z += 1

canvas = Canvas(width=ww, height=hh)
canvas.pack()


# a square
xy = [(50, 50), (150, 50), (150, 150), (50, 150)]

polygon_item = canvas.create_polygon(xy)

center = ww/2, hh/2

def getangle(event):
    dx = canvas.canvasx(event.x) - center[0]
    dy = canvas.canvasy(event.y) - center[1]
    print dx,dy
    try:
        return complex(dx, dy) / abs(complex(dx, dy))
    except ZeroDivisionError:
        return 0.0 # cannot determine angle

def getspinangle():
    x,y = spin[z]
    dx = x - center[0]
    dy = y - center[1]
    return complex(dx, dy) / abs(complex(dx, dy))

def press(event):
    # calculate angle at start point
    global start
    start = getangle(event)

def motion(event):
    # calculate current angle relative to initial angle
    global start, delay
    delay = time.clock()+1
    angle = getangle(event) / start
    offset = complex(center[0], center[1])
    newxy = []
    for x, y in xy:
        v = angle * (complex(x, y) - offset) + offset
        newxy.append(v.real)
        newxy.append(v.imag)
    canvas.itemconfig(polygon_item, fill='green')
    canvas.coords(polygon_item, *newxy)

canvas.bind("<Button-1>", press)
canvas.bind("<B1-Motion>", motion)

z = 0
Lz = len(spin)
delay = 0
while 1:
    if delay < time.clock():
        offset = complex(center[0], center[1])
        newxy = []
        angle = getspinangle()
        z += 1
        z = z%Lz
        for x, y in xy:
            v = angle * (complex(x, y) - offset) + offset
            newxy.append(v.real)
            newxy.append(v.imag)
        canvas.itemconfig(polygon_item, fill='orange')
        canvas.coords(polygon_item, *newxy)
        delay = time.clock()+0.1
    canvas.update()

mainloop()