Lay out a linearly paged book for bound printing.

booklayout.py

#! /usr/bin/env python

""" Lay out a linearly paged book for bound printing.

Described in this post:
    http://micahelliott.com/2008/12/from-e-book-to-real-book/

Additions to post:
 * Firefox does not support the layout, so need to generate PDF.
 * Dad laughs at my process.
 * Mac allows flipping/rotating, would be nice for folding in linux.
 * Add some terminology.
 * Describe gray-scale, low quality are sufficient and fast.
 * Discuss printer ink market scam.

Todo features:
 * Start on any given page. Eg, for print a book in two halves.
 * Or simplest to just allow a range; eg, 119:220
 * Redo algorithm for print full one-sided stack, then flipping to do
   other half.
 * Specify which page is blank for repeating at end.
 * Warnings about pages not divisible by 8.
 * Use optparse for start_page, end_page, half_stack, warning.
 * Specify "skip" pages for pages/sections to be omitted.
 * Specify cover page.
"""

__author__    = 'Micah Elliott http://MicahElliott.com'
__version__   = '0.1'
__copyright__ = 'WTFPL http://sam.zoy.org/wtfpl/'

import sys

USAGE = 'usage: booklayout npages'
try:
    orig_nminis = int(sys.argv[1])
except:
    print USAGE
    raise SystemExit

### Set shrinkage ratio for printing.
mpb = 4         # minis-per-big ratio
mpp = mpb * 2   # minis per (2-sided) page

### Pad blank pages with last page, hoping it's a blank.
#blank_pad = 'BLANK'
blank_pad = orig_nminis

if orig_nminis % mpp == 0:
    nminis = orig_nminis
else:
    # Division is really a floor.
    ##23 / 4 * 4 + 4
    nminis = orig_nminis / mpp * mpp + mpp
###print nminis

def blank(page):
    if page > orig_nminis: return blank_pad
    else: return page

pages = []
i, j = 1, nminis
while i < nminis/2:
    ##16,1  14,3
    ##2,15  4,13
    front = [j,   i,   j-2, i+2]
    back  = [i+1, j-1, i+3, j-3]
    front_back = [blank(page) for page in front+back]
    pages.append( ','.join(map(str, front_back)) )
    i += mpb
    j -= mpb

### Generate result to send to printer.
# Assuming printer can pad with 'b's.
pages_csv = ','.join(pages)
print pages_csv

### For starting at offset.
# Incomplete, hard-coded.
start_page = 119
pages_lst = pages_csv.split(',')
offset_pages = [str( int(pg) + (start_page-1) ) for pg in pages_lst]
print '\nOffset of', start_page
print ','.join(offset_pages)