PDF page cropping

crop.py

#!/usr/bin/env python

from pyPdf.pdf import PdfFileReader, PdfFileWriter, PageObject

import glob
import os

INPUT_DIR = 'input'
OUTPUT_DIR = 'output'

def main():
    input_glob = os.path.normpath(INPUT_DIR + os.sep + '*.pdf')

    for pdf_file in glob.glob(input_glob):
        output_pdf = crop(pdf_file)

        # Construct path of output file
        filename = os.path.basename(pdf_file)
        output_path = os.path.join(OUTPUT_DIR, filename)

        # Write output pdf to file
        output_stream = file(output_path, 'wb')
        output_pdf.write(output_stream)
        output_stream.close()


def crop(pdf_file):

    # Create pdf reader/writer for input/output
    input = PdfFileReader(file(pdf_file, 'rb'))
    output = PdfFileWriter()

    num_pages = input.getNumPages()

    (width, height) = (217, 161)

    for pagenum in range(num_pages):

        current_page = input.getPage(pagenum)

        if pagenum % 2 == 0:
            lower_lefts = [ (70, 576), (70, 356), (70, 136) ]
        else:
            lower_lefts = [ (68, 561), (68, 341), (68, 121) ]

        for lower_left in lower_lefts:

            page = PageObject(current_page.pdf)
            page.update(current_page)

            (x_ll, y_ll) = lower_left

            x_ur = x_ll + width
            y_ur = y_ll + height

            upper_right = (x_ur, y_ur)

            page.trimBox.lowerLeft = lower_left
            page.trimBox.upperRight = upper_right

            page.cropBox.lowerLeft = lower_left
            page.cropBox.upperRight = upper_right

            output.addPage(page)

    return output


if __name__ == '__main__':
    main()