pdf joiner

pdf_join.py

#!/Users/ph/anaconda2/bin/python
# Suppose, 
# ls pdf_folder/
# cover.pdf   even174.pdf even352.pdf odd1.pdf    odd175.pdf
# # number is starting page, `even*` is in reverse order, `odd*` is in right order.
# # cover.pdf includes 3 pages, 1,2 are front pages and 3 is last cover.

from PyPDF2 import PdfFileReader, PdfFileWriter
import glob
import os
import argparse
import pdb

parser = argparse.ArgumentParser()
parser.add_argument('pdffolder', type=str)
parser.add_argument('--out', type=str, default='out.pdf')
args = parser.parse_args()

assert os.path.exists(args.pdffolder)
assert not os.path.exists(args.out)

pages = {}
minus_pages = {} # zeroth page does not exist.
totalpage = 0 
for f in glob.glob(args.pdffolder + '/*.pdf'):
    pfr = PdfFileReader(f)
    pagenum = pfr.getNumPages()
    ff = f.replace(args.pdffolder, '') 
    ff = ff.replace('/','')
    if ff.startswith('odd'):
        totalpage += pagenum
        ffx = ff.replace('odd','')
        ffx = ffx.replace('.pdf', '') 
        startidx = int(ffx)
        for i in range(pagenum):
            idx = i*2 + startidx
            if idx > 0:
                pages[idx] = pfr.getPage(i)
            else: # idx < 0
                minus_pages[-idx] = pfr.getPage(i)
    elif ff.startswith('even'):
        totalpage += pagenum
        ffx = ff.replace('even','')
        ffx = ffx.replace('.pdf', '') 
        endidx = int(ffx)
        for i in range(pagenum):
            idx = endidx - i*2
            if idx > 0:
                pages[idx] = pfr.getPage(i)
            else:
                minus_pages[-idx] = pfr.getPage(i)
assert totalpage == len(pages) + len(minus_pages)

r = PdfFileWriter()
if len(minus_pages)>0:
    stpg = max(minus_pages.keys())
    print('before first page, we have %d pages'%stpg)
    for i in range(stpg, 0, -1):
        r.addPage(minus_pages[i])

stpg = min(pages.keys())
edpg = max(pages.keys())
if stpg>1:
    assert len(minus_pages)==0

for i in range(stpg, edpg+1):
    r.addPage(pages[i])
    
coverf = args.pdffolder+'/cover.pdf'
if os.path.exists(coverf):
    cover = PdfFileReader(coverf)
    #assert 3 == cover.getNumPages()
    if cover.getNumPages() > 1:
        r.insertPage(cover.getPage(1), 0)
    r.insertPage(cover.getPage(0), 0)
    if cover.getNumPages() > 2:
        for i in range(2, cover.getNumPages()):
            r.addPage(cover.getPage(i))

r.write(open(args.out, 'wb'))