creating project.

visual_cryptography/visual_cryptography.py

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+from PIL import Image
+import numpy as np
+from json import dumps
+from random import choice
+
+
+class ImageLayer(object):
+    c_0 = (
+        [[0,0,1,1], [0,0,1,1]],
+        [[1,1,0,0], [1,1,0,0]],
+        [[1,0,1,0], [1,0,1,0]],
+        [[0,1,0,1], [0,1,0,1]],
+        [[0,1,1,0], [0,1,1,0]],
+        [[1,0,0,1], [1,0,0,1]],
+    )
+
+    c_1 = (
+        [[0,0,1,1], [1,1,0,0]],
+        [[1,1,0,0], [0,0,1,1]],
+        [[1,0,1,0], [0,1,0,1]],
+        [[0,1,0,1], [1,0,1,0]],
+        [[0,1,1,0], [1,0,0,1]],
+        [[1,0,0,1], [0,1,1,0]],
+    )
+    
+    pixel_width = 2 
+
+    def __init__(self, height, width):
+        self.data = self.get_empty_data(height, width)
+
+    def get_json_string(self):
+        return dumps(self.data)
+
+    def get_empty_data(self, number_of_lines, number_of_columns):
+        data = []
+        for i in range(number_of_lines):
+            data.append(np.array([0]*number_of_columns))
+        return np.array(data)
+
+    def produce_empty_shares(self):
+        sub_pixel_matrix = self.c_0[0]
+        number_of_share_to_produce = len(sub_pixel_matrix)
+        number_of_sub_pixels = len(sub_pixel_matrix[0])
+        
+        current_width = len(self.data[0])
+        current_height = len(self.data)
+        
+        ret = [self.get_empty_data(current_height * self.pixel_width, current_width * self.pixel_width) for i in range(len(sub_pixel_matrix))]
+        return ret
+
+    def get_single_empty_share(self):
+        return self.produce_empty_shares()[0]
+
+    def place_sub_pixels_in_shares(self, line, col, shares, sub_pixel_matrix):
+        number_of_sub_pixels = len(sub_pixel_matrix[0])
+        for i, share in enumerate(shares):
+            for l in range(line * self.pixel_width, (line + 1) * self.pixel_width ):
+                for c in range(col * self.pixel_width, (col + 1) * self.pixel_width):
+                    share[l][c] = sub_pixel_matrix[i][(l % self.pixel_width) * self.pixel_width + (c % self.pixel_width)]
+
+    def get_pixel_value_in_share(self, x, y, share):
+        pixel = [0, 0, 0, 0]
+        pixel[0] = share[2 * x][2 * y]
+        pixel[1] = share[2 * x][2 * y + 1]
+        pixel[2] = share[2 * x + 1][2 * y]
+        pixel[3] = share[2 * x + 1][2 * y + 1]
+        return pixel
+
+    def produce_shares_from_image(self):
+        shares = self.produce_empty_shares()
+        for (x,y), color in np.ndenumerate(self.data):
+            c = self.c_0 if color == 0 else self.c_1
+            self.place_sub_pixels_in_shares(x, y, shares, choice(c))
+        return shares
+
+    def produce_two_shares_from_image(self):
+        return self.produce_shares_from_image()
+
+    def inverse_pixel(self, pixel):
+        return [(e + 1) % 2 for e in pixel]
+
+    def get_cheated_pixel(self, x, y, share, color):
+        pixel = self.get_pixel_value_in_share(x, y, share)
+        if color == 0:
+            return pixel
+        return self.inverse_pixel(pixel)
+
+    def produce_cheated_image_from_other_share(self, share):
+        cheated_share = self.get_single_empty_share()
+        for (x,y), color in np.ndenumerate(self.data):
+            cheated_pixel = self.get_cheated_pixel(x, y, share, color)
+            self.place_sub_pixels_in_shares(x, y, [cheated_share], [cheated_pixel])
+        return cheated_share
+
+
+def cmyk_to_luminance(r, g, b):
+    """
+    takes a RGB color and returns it grayscale value.  See
+    http://www.johndcook.com/blog/2009/08/24/algorithms-convert-color-grayscale/ 
+    for more information
+    """
+    return 0.299 * r + 0.587 * g + 0.114 * b
+
+
+def cmyk_to_black_and_white(r, g, b):
+    black_threshold = 255 / 3
+    if cmyk_to_luminance(r, g, b) > black_threshold:
+        return 0
+    return 1
+
+
+def produce_image_layer_from_real_image(image_path):
+    im = Image.open(image_path).convert('RGB')
+    ret = ImageLayer(*im.size)
+    for i in range(im.size[0]):
+        for j in range(im.size[1]):
+            r, g, b = im.im.getpixel((i,j))
+            ret.data[j][i] = cmyk_to_black_and_white(r, g, b)
+    return ret
+    
+