#!/usr/bin/python

# Crop notebook pages from the book archiver to just the page
# 

from PIL import Image, ImageDraw
from math import sqrt
import os.path
import sys, getopt

#Color point settings
white_pt = (150, 150, 150)
brown_pt= (98, 75, 60)

#Minimum number of paper pixels in a row/column to keep that row/col
keepThreshold = 50

# calculate distance in RGB color space
def colorDist(pt_a, pt_b):
	dx = pt_a[0] - pt_b[0]
	dy = pt_a[1] - pt_b[1]
	dz = pt_a[2] - pt_b[2]
	return sqrt((dx * dx) + (dy * dy) + (dz * dz))

# get the top and bottom crop rows
def getHorizCrop(scan_range, height, pix):
	for x in scan_range:
		white_count = 0
		for y in range(0, height):
			if colorDist(pix[x,y], white_pt) < colorDist(pix[x,y], brown_pt):
				#It's a white pixel
				white_count += 1
				if white_count > keepThreshold:
					return x

#get the left and right crop columns
def getVertCrop(scan_range, width, pix):
	for y in scan_range:
		white_count = 0
		for x in range(0, width):
			if colorDist(pix[x,y], white_pt) < colorDist(pix[x,y], brown_pt):
				#It's a white pixel
				white_count += 1
				if white_count > keepThreshold:
					return y

def isImage(filename):
	try:
		i=Image.open(filename)
		return i.format in ('JPEG', 'GIF', 'PNG')
	except IOError:
		return False

def autoCrop(imageFileName):
	im = Image.open(imageFileName)
	pix = im.load()
	width, height = im.size;

	left = getHorizCrop(range(0,width), height, pix)
	top = getVertCrop(range(0,height), width, pix)
	right = getHorizCrop(range(width-1, 0, -1), height, pix)
	bottom = getVertCrop(range(height-1, 0, -1), width, pix)

	# Crop the box defined by ((left, top), (right, bottom))
	im = im.crop((left, top, right, bottom))

	#Save the image
	prefix, ext = os.path.splitext(imageFileName)
	im.save(prefix + "_cropped" + ext)

def main():
	try: 
		opts, args = getopt.getopt(sys.argv[1:], "h", ["help"])
	except getopt.error, msg:
		print msg
		print "To get help use -h or --help"
		sys.exit(2)
	for o, a in opts:
		if o in ("-h", "--help"):
			print "There's just no helping some people."
			sys.exit(0)
	for arg in args:
		if isImage(arg):
				autoCrop(arg)
		else:
				print arg + " is not a directory, skipped."
	
if __name__ == "__main__":
	main()