opencv read write image

#!  usr/bin/python
#   coding=utf-8

import numpy as np
import cv2
import os


#   opencv read write image
img = np.zeros((3, 3), dtype=np.uint8)
img = cv2.cvtColor(img, cv2.COLOR_GRAY2RGB)

image = cv2.imread('test.jpg')

print image.shape
print image.size
print image.dtype

cv2.imwrite('test1.png', image)

#   IMREAD_UNCHANGED = -1
#   IMREAD_GRAYSCALE =  0
#   IMREAD_COLOR     =  1 
#   IMREAD_ANYDEPTH  =  2
#   IMREAD_ANYCOLOR  =  4
#   IMREAD_LOAD_GDAL =  8
gray_image = cv2.imread('test.jpg', cv2.IMREAD_GRAYSCALE)
cv2.imwrite('IMREAD_GRAYSCALE.png', gray_image)

random_byte_array = bytearray(os.urandom(120000))
flat_numpy_array = np.array(random_byte_array)
gray_image2 = flat_numpy_array.reshape(300, 400)
cv2.imwrite('gray_image2.png', gray_image2)
bgr_image = flat_numpy_array.reshape(100, 400, 3)
cv2.imwrite('color_image.png', bgr_image)

# image.itemset((200, 200, 0), 0)
# print image.item(200, 200, 0)
# image[ : : 2] = 0
my_roi = image[0: 300, 0:300]
image[300:600, 300:600] = my_roi
cv2.imwrite('test2.png', image)


#   opencv show image

cv2.imshow('gray-image', gray_image)
cv2.waitKey()
cv2.destroyAllWindows()