scottrogowski · August 21, 2024 21:23 · Jul 15, 2015 · Jul 15, 2015
diff --git a/pixelate.py b/pixelate.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 # This script will pixelate most jpg and png images
+# It will both show you the result and save it
 
 import sys
 

diff --git a/pixelate.py b/pixelate.py
@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+
+# This script will pixelate most jpg and png images
+
+import sys
+
+import matplotlib.pyplot as plt
+import numpy as np
+import PIL.Image as Image
+import scipy.misc as misc
+
+def load_img(filename):
+    # boilerplate code to open an image and make it editable
+    img = Image.open(filename)
+    data = np.array(img)
+    return data
+
+def all_square_pixels(row, col, square_h, square_w):
+    # Every pixel for a single "square" (superpixel)
+    # Note that different squares might have different dimensions in order to
+    # not have extra pixels at the edge not in a square. Hence: int(round())
+    for y in xrange(int(round(row*square_h)), int(round((row+1)*square_h))):
+        for x in xrange(int(round(col*square_w)), int(round((col+1)*square_w))):
+            yield y, x
+
+def make_one_square(img, row, col, square_h, square_w):
+    # Sets all the pixels in img for the square given by (row, col) to that
+    # square's average color
+    pixels = []
+
+    # get all pixels
+    for y, x in all_square_pixels(row, col, square_h, square_w):
+        pixels.append(img[y][x])
+
+    # get the average color
+    av_r = 0
+    av_g = 0
+    av_b = 0
+    for r, g, b in pixels:
+        av_r += r
+        av_g += g
+        av_b += b
+    av_r /= len(pixels)
+    av_g /= len(pixels)
+    av_b /= len(pixels)
+
+    # set all pixels to that average color
+    for y, x in all_square_pixels(row, col, square_h, square_w):
+        img[y][x] = (av_r, av_g, av_b)
+
+if __name__ == "__main__":
+    try:
+        filename = sys.argv[1]
+    except IndexError:
+        filename = raw_input("Image to pixelate? ")
+    img = load_img(filename)
+
+    # Figure out the dimensions of each square
+    # We want:
+    # 1. Square width and height should be about the same
+    # 2. No leftover pixels at the edges
+    # This means that some squares might have one more or one less pixel
+    # depending on rounding
+    num_cols = int(raw_input("How many squares from left to right? "))
+    square_w = float(img.shape[1]) / num_cols
+    num_rows = int(round(img.shape[0] / square_w))
+    square_h = float(img.shape[0]) / num_rows
+
+    # overwrite each square with the average color, one by one
+    for row in range(num_rows):
+        for col in range(num_cols):
+            make_one_square(img, row, col, square_h, square_w)
+
+    # show the image
+    plt.axis('off')
+    plt.imshow(img)
+    plt.show()
+
+    # save the image
+    filename_parts = filename.rsplit('.', 1)
+    filename_parts[0] += '_pixelated'
+    filename = '.'.join(filename_parts)
+    print "Saving as", filename
+    misc.imsave(filename, img)