import sys

  import cv2
  import numpy as np
  
  def Skeletization(img, shape, size):
  	if shape == '1':
  		shape = cv2.MORPH_RECT
  	elif shape == '2':
  		shape = cv2.MORPH_ELLIPSE
  	elif shape == '3':
  		shape = cv2.MORPH_CROSS
  	else:
  		return
  	
  	cv2.normalize(img, img, 0, 255, cv2.NORM_MINMAX)
  	skeleton = np.zeros(img.shape, np.uint8)
  	eroded = np.zeros(img.shape, np.uint8)
  	temp = np.zeros(img.shape, np.uint8)
  
  	_,thresh = cv2.threshold(img, 127, 255, 0)
  	
  	kernel = cv2.getStructuringElement(shape,(int(size), int(size)))
  
  	while(True):
  		cv2.erode(thresh, kernel, eroded)

  		cv2.dilate(eroded, kernel, temp)
  		cv2.subtract(thresh, temp, temp)
  		cv2.bitwise_or(skeleton, temp, skeleton)
  		thresh, eroded = eroded, thresh 

  		if cv2.countNonZero(thresh) == 0:

  			break
  
  	kernel = np.ones((20,20), np.uint8)
  	skeleton = cv2.morphologyEx(skeleton, cv2.MORPH_CLOSE, kernel)
  	cv2.imwrite('DefaultSkeleton.png', skeleton)
  	cv2.imshow('skeleton', skeleton)
  	return skeleton
  
  def KernelChoice():
  	image = None
  	size = '0'
  	choice = '0'
  	print('\t\tSkeleton Menu\n')
  	while (image is None):

  		if sys.version_info >= (3, 0):
  			image = str(input('\tImage to use ? By default couleur.png \n'))
  		else:
  			image = str(raw_input('\tImage to use ? By default couleur.png \n'))

  		if not image:
  			image = 'FondNoir.png'
  		image = cv2.imread(str(image),0)
  	print('\t1. Rectangle\n\t2. Ellipse\n\t3. Cross\n')

  	while choice < '1' or choice > '3':
  		if sys.version_info >= (3, 0):
  			choice = input('\n\tKernel Choice. Rectangle by Default\n')
  		else :
  			choice = raw_input('\n\tKernel Choice. Rectangle by Default\n')

  		if not choice:
  			choice = '1'
  	while int(size) % 2 == 0:

  		if sys.version_info >= (3, 0):
  			size = input('\n\tPlease specify the kernel size (Odd number). By default it\'s 3\n')
  		else :
  			size = raw_input('\n\tPlease specify the kernel size (Odd number). By default it\'s 3\n')

  		if not size:
  			size = '3'
  	Skeletization(image, choice, size)
  
  	cv2.waitKey(0)
  	cv2.destroyAllWindows()
  	
  	return