average_machine.py

#!/usr/bin/python

__author__ = "Arlo Carreon <http://arlocarreon.com>"


# Purpose: 
# generate an "average" image from local directory



import sys
import os
import re
import math
import Image
import time

# Type of extensions you are willing to accept
ext = "JPG|jpeg|jpg|png"
# Base path for source images and average destination
source_path = "./source/"
average_path = "./average/"


# Function grabs all images in a folder
def get_photos_from_directory( path ):
	listing = os.listdir(path)
	images = []
	regex_str = '.*\.['+ext+']'
	print "Looking for matching files: "+regex_str
	for infile in listing:
		if re.match( regex_str, infile, re.I|re.X ):
			images.append(infile)
	return images

def resize(im, screen, standard_area):
 
 (screen_width, screen_height) = screen
 (width, height) = im.size
 
 # resize here to all occupy about the same area on screen.
 area = width * height
 factor = math.sqrt( standard_area * 1.0 / area )
 width *= factor
 height *= factor
 
 # but stay within the maximum screen.
 if width > screen_width or height > screen_height:
 # landscape
 if width > height: 
 width = screen_width
 height *= screen_width / width
 # portrait
 else: 
 width *= screen_height / height
 height = screen_height
 
 width = int(width)
 height = int(height)
 
 return im.resize((width,height), Image.BICUBIC)


def create_average(screen, photos):
 
 debug("starting")

 # some geometry
 (screen_width, screen_height) = screen
 center_x = screen_width / 2;
 center_y = screen_height / 2;

 # we will resize all photos to have an area around this.
 phi = (1 + math.sqrt(5)) / 2
 standard_area = screen_width * (screen_width/phi)
 

 # prototype black screen all images get pasted onto. 
 black = Image.new("RGB", screen, "black")
 average = black.copy()

 
 for i in range(len(photos)):

 debug("processing >> %s" % photos[i])
 
 try:
 im = load_image(photos[i]);
 except: 
 debug("Bad Image? Script no likie.")
 continue
 
 im = resize(im, screen, standard_area);
 
 # paste photo in the center of a black screen. 
 (im_width, im_height) = im.size
 offset_x = center_x - im_width / 2;
 offset_y = center_y - im_height / 2;
 
 im_frame = black.copy()
 im_frame.paste(im, (offset_x,offset_y))
 
 # and blend this with our average 
 alpha = 1.0/(i+1) # <-- clever part. Get average in constant memory.
 # perhaps too clever. 
 # images where most of the detail is just squished into one or two
 # bits of depth. This may account for the slow darkening (?)
 # may be better to combine images in a tree
 average = Image.blend(average, im_frame, alpha);

 # is this necessary? jclark had it.
 del im

 return average
 

def load_image(photo):
 im = Image.open(source_path+photo)
 return im
 

def debug(msg):
 sys.stderr.write(msg + "\n")

def main(*argv):
 from getopt import getopt, GetoptError
 global source_path

 try:
 (opts, args) = getopt(argv[1:], 'p:w:h:f:n:u:s:a:', ['page', 'width', 'height', 'file', 'number','unique','source','average'])
 except GetoptError, e:
 print e
 print __doc__
 return 1

 width = 500
 height = 500
 n = 100
 unique_owners = False
 start_page = 0 
 
 for o, a in opts:
 if o in ('-w', '--width'):
 width = int(a)
 elif o in ('-h', '--height'):
 height = int(a)
 elif o in ('-f', '--file'):
 file = average_path + a
 elif o in ('-n', '--number'):
 n = int(a)
 elif o in ('-u', '--unique'):
 unique_owners = True
 elif o in ('-p', '--page'):
 start_page = int(a)
 elif o in ('-s', '--source'):
	 source_path = a
	elif o in ('-a', '--average'):
	 average_path = a
 else:
 print "Unknown argument: %s" % o
 print __doc__
 return 1

 # Set the screen
 screen = (width, height)

 file = average_path + str(time.time()) + '.jpg'

 photos = get_photos_from_directory(source_path)
 average = create_average(screen, photos)
 average.save(file)

if __name__ == '__main__':
 sys.exit(main(*sys.argv))