def draw_koch(n=3, polygon=6):
    """绘画科赫雪花

    :param n: 迭代次数
    :param polygon: 多边形雪花
    """
    pen = turtle.Pen()
    turtle.title('科赫雪花')
    pen.speed(0)
    r = pen.screen.canvwidth / 2
    pen.penup()
    pen.goto(-r, 0)
    pen.pendown()
    a = 180 - (polygon - 2) * 180 / polygon  # 计算多边形旋转的角度,计算公式
    # 多边形的内角和公式（n-2）*180/n
    for i in range(polygon):
        angle = a * (1 - i)
        pen.setheading(angle)
        koch(pen, n, r)
    turtle.done() 

def drawBitmap(w_image):
    print('Reducing the colors...')
    Z = w_image.reshape((-1, 3))

    # convert to np.float32
    Z = np.float32(Z)

    # define criteria, number of clusters(K) and apply kmeans()
    criteria = (cv2.TERM_CRITERIA_EPS, 10, 1.0)
    global K
    ret, label, center = cv2.kmeans(
        Z, K, None, criteria, 10, cv2.KMEANS_RANDOM_CENTERS)

    # Now convert back into uint8, and make original image
    center = np.uint8(center)
    res = center[label.flatten()]
    res = res.reshape(w_image.shape)
    no = 1
    for i in center:
        sys.stdout.write('\rDrawing: %.2f%% [' % (
            no / K * 100) + '#' * no + ' ' * (K - no) + ']')
        no += 1
        res2 = cv2.inRange(res, i, i)
        res2 = cv2.bitwise_not(res2)
        cv2.imwrite('.tmp.bmp', res2)
        os.system('potrace.exe .tmp.bmp -s --flat')
        # print(i)
        drawSVG('.tmp.svg', '#%02x%02x%02x' % (i[2], i[1], i[0]))
    os.remove('.tmp.bmp')
    os.remove('.tmp.svg')
    print('\n\rFinished, close the window to exit.')
    te.done() 

def draw(self):  # 绘画
        pen = turtle.Pen()
        turtle.title('康托三分集')
        pen.width(2)
        for index, dot in enumerate(self.dot):
            for x, y in dot:
                pen.penup()
                pen.goto(x=x, y=100 - index * 10)
                pen.pendown()
                pen.forward(y - x)
        turtle.done()