[misc] / bookmaker.py

#!/usr/bin/env python3
"""
bookmaker.py is a helper for optimizing PDFs for the production of small self-printed, self-bound physical books.  Towards this goal it offers various PDF manipulation options that may also be used indepéndently and for other purposes.
"""
help_epilogue = """
OVERVIEW OF TARGET USAGE:

By cropping with -c and studying the results, define the areas of the input PDF's pages you want visible.  Then, with--nup4, map those areas onto 4 input pages per 1 output page, arranged in such a way that double-sided print-out of those output pages can be cut, folded, and bound (helped by addition of stencils for small incisions to carry rubber bands or the like) into a small A6 book.  Each unit of 8 pages from the input PDF is mapped by --nup4 onto two pages representing two sides of a (no-tumble-duplex-printed) A4 paper:

                      +-------=-------+                     __________________
 (front)  (back)      | 4 | 1 = 2 | 3 |             4      /=|===|============
+-------=-------+ ==> +-------=-------+ ===>  _/|\_ v      >=|===|============
| 4 | 1 = 2 | 3 |                            /  |  \_      \=|===|============
|-------=-------|     +-------=-------+ 1-> | 2 | 3 |      | \   / <- cut out!
| 8 | 5 = 6 | 7 | ==> | 8 | 5 = 6 | 7 |     | _/ \_ |      |  \ |
+-------=-------+     +-------=-------+     |/     \|      |   \| (p. 5)

To turn this paper into a small 8-pages book, first cut it into two A5 papers along its horizontal middle.  Fold both A5's by their vertical middles, with pages 2-3 and 7-6 on the folds' insides.  You now have two 4-page A6 "books" of pages 1-4 and pages 5-8.  Fold both closed and (counter-intuitively) stack the second one on top of the first one (creating a temporary page order of 5,6,7,8,1,2,3,4).  This reveals a small stencil on the top left of page 5 – cut it out, with all other pages folded and aligned under it, creating a small notch in the upper "inner" corner of all pages.  Turn around the stack to find a mirror stencil on the bottom and repeat the cutting.  Each page now has cuts on top and bottom of its inner margins into which a rubber band can be hooked, or through which a string may be looped and tied, to bind the page's inner margins into a kind of book spine.  You may now swap the order of the 4-page books back into a proper final page order (of 1,2,3,4,5,6,7,8) and repeat the whole process for each further --nup4 output paper.

COMMAND EXAMPLES:

Concatenate two PDFs A.pdf and B.pdf to COMBINED.pdf:
    bookmaker.py --input_file A.pdf --input_file B.pdf --output_file COMBINED.pdf

Produce OUTPUT.pdf containing all pages of (inclusive) page number range 3-7 from INPUT.pdf:
    bookmaker.py -i INPUT.pdf --page_range 3-7 -o OUTPUT.pdf

Produce COMBINED.pdf from A.pdf's first 7 pages, B.pdf's pages except its first two, and all pages of C.pdf:
    bookmaker.py -i A.pdf -p start-7 -i B.pdf -p 3-end -i C.pdf -o COMBINED.pdf

Crop each page 5cm from the left, 10cm from the bottom, 2cm from the right, and 0cm from the top:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf --crops "5,10,2,0"

Include all pages from INPUT.pdf, but only crop pages 10-20 by 5cm each from bottom and top:
    bookmaker.py -i INPUT.pdf -c "10-20:0,5,0,5" -o OUTPUT.pdf

Same crops for pages 10-20, but also crop all pages 30 and later by 3cm each from left and right:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf -c "10-20:0,5,0,5" -c "30-end:3,0,3,0"

Rotate by 90° pages 3, 5, 7; rotate page 7 once more by 90% (i.e. 180° in total):
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf --rotate 3 -r 5 -r 7 -r 7

Initially declare 5cm crop from the left and 1cm crop from right, but alternate direction between even and odd pages:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf -c "5,0,1,0" --symmetry

Quarter each OUTPUT.pdf page to carry 4 pages from INPUT.pdf, draw stencils into inner margins for cuts to carry binding strings:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf --nup4

Same --nup4, but define a printable-region margin of 1.3cm to limit the space for the INPUT.pdf pages in OUTPUT.pdf page quarters:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf -n --print_margin 1.3

Same --nup4, but draw lines marking printable-region margins, page quarters, spine margins:
    bookmaker.py -i INPUT.pdf -o OUTPUT.pdf -n --analyze

FURTHER NOTES:

For arguments like -p, page numbers are assumed to start with 1 (not 0, which is treated as an invalid page number value).

The target page shape so far is assumed to be A4 in portrait orientation; bookmaker.py normalizes all pages to this format before applying crops, and removes any source PDF /Rotate commands (for their production of landscape orientations).
"""
import argparse
import io
import os
import sys
from collections import namedtuple

def handled_error_exit(msg):
    print(f"ERROR: {msg}")
    sys.exit(1)

try:
    import pypdf
except ImportError:
    handled_error_exit("Can't run at all without pypdf installed.")

# some general paper geometry constants
POINTS_PER_CM = 10 * 72 / 25.4
A4_WIDTH = 21 * POINTS_PER_CM
A4_HEIGHT = 29.7 * POINTS_PER_CM
A4 = (A4_WIDTH, A4_HEIGHT)

# constants specifically for --nup4
A4_HALF_WIDTH = A4_WIDTH / 2
A4_HALF_HEIGHT = A4_HEIGHT / 2
CUT_DEPTH = 1.95 * POINTS_PER_CM
CUT_WIDTH = 1.05 * POINTS_PER_CM
MIDDLE_POINT_DEPTH = 0.4 * POINTS_PER_CM
INNER_SPINE_MARGIN_PER_PAGE = 1 * POINTS_PER_CM
QUARTER_SCALE_FACTOR = 0.5
PAGE_ORDER_FOR_NUP4 = (3,0,7,4,1,2,5,6)


class PageCrop:

    def __init__(self, left_cm=0, bottom_cm=0, right_cm=0, top_cm=0):
        self.left_cm = left_cm
        self.bottom_cm = bottom_cm
        self.right_cm = right_cm
        self.top_cm = top_cm
        self.left = float(self.left_cm) * POINTS_PER_CM
        self.bottom = float(self.bottom_cm) * POINTS_PER_CM
        self.right = float(self.right_cm) * POINTS_PER_CM
        self.top = float(self.top_cm) * POINTS_PER_CM
        zoom_horizontal = A4_WIDTH / (A4_WIDTH - self.left - self.right)
        zoom_vertical = A4_HEIGHT / (A4_HEIGHT - self.bottom - self.top)
        if (zoom_horizontal > 1 and zoom_vertical < 1) or (zoom_horizontal < 1 and zoom_vertical > 1):
            raise HandledException("-c: crops would create opposing zoom directions")
        elif zoom_horizontal + zoom_vertical > 2:
            self.zoom = min(zoom_horizontal, zoom_vertical)
        else:
            self.zoom = max(zoom_horizontal, zoom_vertical)

    def __str__(self):
        return str(vars(self))

    @property
    def format_in_cm(self):
        return f"left {self.left_cm}cm, bottom {self.bottom_cm}cm, right {self.right_cm}cm, top {self.top_cm}cm"

    @property
    def remaining_width(self):
        return A4_WIDTH - self.left - self.right

    @property
    def remaining_height(self):
        return A4_HEIGHT - self.bottom - self.top

    def give_mirror(self):
        return PageCrop(left_cm=self.right_cm, bottom_cm=self.bottom_cm, right_cm=self.left_cm, top_cm=self.top_cm)


class Nup4Geometry:

    def __init__(self, margin_cm):
        self.margin = margin_cm * POINTS_PER_CM
        self.shrink_for_margin = (A4_WIDTH - 2 * self.margin)/A4_WIDTH
        # NB: We define spine size un-shrunk, but .shrink_for_spine is used with values shrunk for the margin, which we undo here.
        spine_part_of_page = (INNER_SPINE_MARGIN_PER_PAGE / A4_HALF_WIDTH) / self.shrink_for_margin
        self.shrink_for_spine = 1 - spine_part_of_page


class HandledException(Exception):
    pass


def parse_args():
    parser = argparse.ArgumentParser(description=__doc__, epilog=help_epilogue, formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument("-i", "--input_file", action="append", required=True, help="input PDF file")
    parser.add_argument("-o", "--output_file", required=True, help="output PDF file")
    parser.add_argument("-p", "--page_range", action="append", help="page range, e.g., '2-9' or '3-end' or 'start-14'")
    parser.add_argument("-c", "--crops", action="append", help="cm crops left, bottom, right, top – e.g., '10,10,10,10'; prefix with ':'-delimited page range to limit effect")
    parser.add_argument("-r", "--rotate_page", type=int, action="append", help="rotate page of number by 90° (usable multiple times on same page!)")
    parser.add_argument("-s", "--symmetry", action="store_true", help="alternate horizontal crops between odd and even pages")
    parser.add_argument("-n", "--nup4", action='store_true', help="puts 4 input pages onto 1 output page, adds binding cut stencil")
    parser.add_argument("-a", "--analyze", action="store_true", help="in --nup4, print lines identifying spine, page borders")
    parser.add_argument("-m", "--print_margin", type=float, default=0.43, help="print margin for --nup4 in cm (default 0.43)")
    return parser.parse_args()


def validate_inputs_first_pass(args):
    for filename in args.input_file:
        if not os.path.isfile(filename):
            raise HandledException(f"-i: {filename} is not a file")
        try:
            with open(filename, 'rb') as file:
                pypdf.PdfReader(file)
        except pypdf.errors.PdfStreamError:
            raise HandledException(f"-i: cannot interpret {filename} as PDF file")
    if args.page_range:
        for p_string in args.page_range:
            validate_page_range(p_string, "-p")
        if len(args.page_range) > len(args.input_file):
            raise HandledException("-p: more --page_range arguments than --input_file arguments")
    if args.crops:
        for c_string in args.crops:
            initial_split = c_string.split(':')
            if len(initial_split) > 2:
                raise HandledException(f"-c: cropping string has multiple ':': {c_string}")
            page_range, crops = split_crops_string(c_string)
            crops = crops.split(",")
            if page_range:
                validate_page_range(page_range, "-c")
            if len(crops) != 4:
                raise HandledException(f"-c: cropping does not contain exactly three ',': {c_string}")
            for crop in crops:
                try:
                    float(crop)
                except ValueError:
                    raise HandledException(f"-c: non-number crop in: {c_string}")
    if args.rotate_page:
        for r in args.rotate_page:
            try:
                int(r)
            except ValueError:
                raise HandledException(f"-r: non-integer value: {r}")
            if r < 1:
                raise HandledException(f"-r: value must not be <1: {r}")
    try:
        float(args.print_margin)
    except ValueError:
        raise HandledException(f"-m: non-float value: {arg.print_margin}")


def validate_page_range(p_string, err_msg_prefix):
    prefix = f"{err_msg_prefix}: page range string"
    if '-' not in p_string:
        raise HandledException(f"{prefix} lacks '-': {p_string}")
    tokens = p_string.split("-")
    if len(tokens) > 2:
        raise HandledException(f"{prefix} has too many '-': {p_string}")
    for i, token in enumerate(tokens):
        if token == "":
            continue
        if i == 0 and token == "start":
            continue
        if i == 1 and token == "end":
            continue
        try:
            int(token)
        except ValueError:
            raise HandledException(f"{prefix} carries value neither integer, nor 'start', nor 'end': {p_string}")
        if int(token) < 1:
            raise HandledException(f"{prefix} carries page number <1: {p_string}")
    start = -1
    end = -1
    try:
        start = int(tokens[0])
        end = int(tokens[1])
    except ValueError:
        pass
    if start > 0 and end > 0 and start > end:
        raise HandledException(f"{prefix} has higher start than end value: {p_string}")


def split_crops_string(c_string):
    initial_split = c_string.split(':')
    if len(initial_split) > 1:
        page_range = initial_split[0]
        crops = initial_split[1]
    else:
        page_range = None
        crops = initial_split[0]
    return page_range, crops


def parse_page_range(range_string, pages):
    start_page = 0
    end_page = len(pages)
    if range_string:
        start, end = range_string.split('-')
        if not (len(start) == 0 or start == "start"):
            start_page = int(start) - 1
        if not (len(end) == 0 or end == "end"):
            end_page = int(end)
    return start_page, end_page


def read_inputs_to_pagelist(args_input_file, args_page_range):
    pages_to_add = []
    opened_files = []
    new_page_num = 0
    for i, input_file in enumerate(args_input_file):
        file = open(input_file, 'rb')
        opened_files += [file]
        reader = pypdf.PdfReader(file)
        range_string = None
        if args_page_range and len(args_page_range) > i:
            range_string = args_page_range[i]
        start_page, end_page = parse_page_range(range_string, reader.pages)
        if end_page > len(reader.pages):  # no need to test start_page cause start_page > end_page is checked above
            raise HandledException(f"-p: page range goes beyond pages of input file: {range_string}")
        for old_page_num in range(start_page, end_page):
            new_page_num += 1
            page = reader.pages[old_page_num]
            pages_to_add += [page]
            print(f"-i, -p: read in {input_file} page number {old_page_num+1} as new page {new_page_num}")
    return pages_to_add, opened_files


def validate_inputs_second_pass(args, pages_to_add):
    if args.crops:
        for c_string in args.crops:
            page_range, _= split_crops_string(c_string)
            if page_range:
                start, end = parse_page_range(page_range, pages_to_add)
                if end > len(pages_to_add):
                     raise HandledException(f"-c: page range goes beyond number of pages we're building: {page_range}")
    if args.rotate_page:
        for r in args.rotate_page:
            if r > len(pages_to_add):
                 raise HandledException(f"-r: page number beyond number of pages we're building: {r}")


def rotate_pages(args_rotate_page, pages_to_add):
    if args_rotate_page:
        for rotate_page in args_rotate_page:
            page = pages_to_add[rotate_page - 1]
            page.add_transformation(pypdf.Transformation().translate(tx=-A4_WIDTH/2, ty=-A4_HEIGHT/2))
            page.add_transformation(pypdf.Transformation().rotate(-90))
            page.add_transformation(pypdf.Transformation().translate(tx=A4_WIDTH/2, ty=A4_HEIGHT/2))
            print(f"-r: rotating (by 90°) page {rotate_page}")


def pad_pages_to_multiple_of_8(pages_to_add):
    mod_to_8 = len(pages_to_add) % 8
    if mod_to_8 > 0:
        old_len = len(pages_to_add)
        for _ in range(8 - mod_to_8):
            new_page = pypdf.PageObject.create_blank_page(width=A4_WIDTH, height=A4_HEIGHT)
            pages_to_add += [new_page]
        print(f"-n: number of input pages {old_len} not required multiple of 8, padded to {len(pages_to_add)}")


def normalize_pages_to_A4(pages_to_add):
    for page in pages_to_add:
        if "/Rotate" in page:  # TODO: preserve rotation, but in canvas?
            page.rotate(360 - page["/Rotate"])
        page.mediabox.left = 0
        page.mediabox.bottom = 0
        page.mediabox.top = A4_HEIGHT
        page.mediabox.right = A4_WIDTH
        page.cropbox = page.mediabox


def collect_per_page_crops_and_zooms(args_crops, args_symmetry, pages_to_add):
    crop_at_page = [PageCrop()] * len(pages_to_add)
    if args_crops:
        for c_string in args_crops:
            page_range, crops = split_crops_string(c_string)
            start_page, end_page = parse_page_range(page_range, pages_to_add)
            prefix = "-c, -t" if args_symmetry else "-c"
            suffix = " (but alternating left and right crop between even and odd pages)" if args_symmetry else ""
            page_crop = PageCrop(*[x for x in crops.split(',')])
            print(f"{prefix}: to pages {start_page + 1} to {end_page} applying crop: {page_crop.format_in_cm}{suffix}")
            for page_num in range(start_page, end_page):
                if args_symmetry and page_num % 2:
                    crop_at_page[page_num] = page_crop.give_mirror()
                else:
                    crop_at_page[page_num] = page_crop
    return crop_at_page


def build_single_pages_output(writer, pages_to_add, crop_at_page):
    print("building 1-input-page-per-output-page book")
    odd_page = True
    for i, page in enumerate(pages_to_add):
        page.add_transformation(pypdf.Transformation().translate(tx=-crop_at_page[i].left, ty=-crop_at_page[i].bottom))
        page.add_transformation(pypdf.Transformation().scale(crop_at_page[i].zoom, crop_at_page[i].zoom))
        page.mediabox.right = crop_at_page[i].remaining_width * crop_at_page[i].zoom
        page.mediabox.top = crop_at_page[i].remaining_height * crop_at_page[i].zoom
        writer.add_page(page)
        odd_page = not odd_page
        print(f"built page number {i+1} (of {len(pages_to_add)})")


def build_nup4_output(writer, pages_to_add, crop_at_page, args_print_margin, args_analyze, canvas_class):
    print("-n: building 4-input-pages-per-output-page book")
    print(f"-m: applying printable-area margin of {args_print_margin}cm")
    if args_analyze:
        print("-a: drawing page borders, spine limits")
    nup4_geometry = Nup4Geometry(args_print_margin)
    pages_to_add, new_i_order = resort_pages_for_nup4(pages_to_add)
    nup4_i = 0
    page_count = 0
    is_front_page = True
    for i, page in enumerate(pages_to_add):
        if nup4_i == 0:
            new_page = pypdf.PageObject.create_blank_page(width=A4_WIDTH, height=A4_HEIGHT)
        corrected_i = new_i_order[i]
        nup4_inner_page_transform(page, crop_at_page[corrected_i], nup4_geometry, nup4_i)
        nup4_outer_page_transform(page, nup4_geometry, nup4_i)
        new_page.merge_page(page)
        page_count += 1
        print(f"merged page number {page_count} (of {len(pages_to_add)})")
        nup4_i += 1
        if nup4_i > 3:
            ornate_nup4(writer, args_analyze, is_front_page, new_page, nup4_geometry, canvas_class)
            writer.add_page(new_page)
            nup4_i = 0
            is_front_page = not is_front_page


def resort_pages_for_nup4(pages_to_add):
    new_page_order = []
    new_i_order = []
    eight_pack = []
    i = 0
    n_eights = 0
    for page in pages_to_add:
        if i == 0:
            eight_pack = []
        eight_pack += [page]
        i += 1
        if i == 8:
            i = 0
            for n in PAGE_ORDER_FOR_NUP4:
                new_i_order += [8 * n_eights + n]
                new_page_order += [eight_pack[n]]
            n_eights += 1
    return new_page_order, new_i_order


def nup4_inner_page_transform(page, crop, nup4_geometry, nup4_i):
    page.add_transformation(pypdf.Transformation().translate(ty=(A4_HEIGHT / crop.zoom - (A4_HEIGHT - crop.top))))
    if nup4_i == 0 or nup4_i == 2:
        page.add_transformation(pypdf.Transformation().translate(tx=-crop.left))
    elif nup4_i == 1 or nup4_i == 3:
        page.add_transformation(pypdf.Transformation().translate(tx=(A4_WIDTH / crop.zoom - (A4_WIDTH - crop.right))))
    page.add_transformation(pypdf.Transformation().scale(crop.zoom * nup4_geometry.shrink_for_spine, crop.zoom * nup4_geometry.shrink_for_spine))
    if nup4_i == 2 or nup4_i == 3:
        page.add_transformation(pypdf.Transformation().translate(ty=-2*nup4_geometry.margin/nup4_geometry.shrink_for_margin))


def nup4_outer_page_transform(page, nup4_geometry, nup4_i):
    page.add_transformation(pypdf.Transformation().translate(ty=(1-nup4_geometry.shrink_for_spine)*A4_HEIGHT))
    if nup4_i == 0 or nup4_i == 1:
        y_section = A4_HEIGHT
        page.mediabox.bottom = A4_HALF_HEIGHT
        page.mediabox.top    = A4_HEIGHT
    if nup4_i == 2 or nup4_i == 3:
        y_section = 0
        page.mediabox.bottom = 0
        page.mediabox.top  =  A4_HALF_HEIGHT
    if nup4_i == 0 or nup4_i == 2:
        x_section = 0
        page.mediabox.left   = 0
        page.mediabox.right  = A4_HALF_WIDTH
    if nup4_i == 1 or nup4_i == 3:
        page.add_transformation(pypdf.Transformation().translate(tx=(1-nup4_geometry.shrink_for_spine)*A4_WIDTH))
        x_section = A4_WIDTH
        page.mediabox.left   = A4_HALF_WIDTH
        page.mediabox.right  = A4_WIDTH
    page.add_transformation(pypdf.Transformation().translate(tx=x_section, ty=y_section))
    page.add_transformation(pypdf.Transformation().scale(QUARTER_SCALE_FACTOR, QUARTER_SCALE_FACTOR))


def ornate_nup4(writer, args_analyze, is_front_page, new_page, nup4_geometry, canvas_class):
    if args_analyze:
        # borders
        packet = io.BytesIO()
        c = canvas_class(packet, pagesize=A4)
        c.setLineWidth(0.1)
        c.line(0, A4_HEIGHT, A4_WIDTH, A4_HEIGHT)
        c.line(0, A4_HALF_HEIGHT, A4_WIDTH, A4_HALF_HEIGHT)
        c.line(0, 0, A4_WIDTH, 0)
        c.line(0, A4_HEIGHT, 0, 0)
        c.line(A4_HALF_WIDTH, A4_HEIGHT, A4_HALF_WIDTH, 0)
        c.line(A4_WIDTH, A4_HEIGHT, A4_WIDTH, 0)
        c.save()
        new_pdf = pypdf.PdfReader(packet)
        new_page.merge_page(new_pdf.pages[0])
    printable_offset_x = nup4_geometry.margin
    printable_offset_y = nup4_geometry.margin * A4_HEIGHT / A4_WIDTH
    new_page.add_transformation(pypdf.Transformation().scale(nup4_geometry.shrink_for_margin, nup4_geometry.shrink_for_margin))
    new_page.add_transformation(pypdf.Transformation().translate(tx=printable_offset_x, ty=printable_offset_y))
    x_left_spine_limit = A4_HALF_WIDTH * nup4_geometry.shrink_for_spine
    x_right_spine_limit = A4_WIDTH - x_left_spine_limit
    if args_analyze or is_front_page:
        packet = io.BytesIO()
        c = canvas_class(packet, pagesize=A4)
    if args_analyze:
        # spine lines
        c.setLineWidth(0.1)
        c.line(x_left_spine_limit, A4_HEIGHT, x_left_spine_limit, 0)
        c.line(x_right_spine_limit, A4_HEIGHT, x_right_spine_limit, 0)
    if is_front_page:
        c.setLineWidth(0.2)
        draw_cut(c, x_left_spine_limit, (1))
        draw_cut(c, x_right_spine_limit, (-1))
    if args_analyze or is_front_page:
        c.save()
        new_pdf = pypdf.PdfReader(packet)
        new_page.merge_page(new_pdf.pages[0])


def draw_cut(canvas, x_spine_limit, direction):
    outer_start_x = x_spine_limit - 0.5 * CUT_WIDTH * direction
    inner_start_x = x_spine_limit + 0.5 * CUT_WIDTH * direction
    middle_point_y =  A4_HALF_HEIGHT + MIDDLE_POINT_DEPTH * direction
    end_point_y =  A4_HALF_HEIGHT + CUT_DEPTH * direction
    canvas.line(inner_start_x, A4_HALF_HEIGHT, x_spine_limit, end_point_y)
    canvas.line(x_spine_limit, end_point_y, x_spine_limit, middle_point_y)
    canvas.line(x_spine_limit, middle_point_y, outer_start_x, A4_HALF_HEIGHT)


def main():
    args = parse_args()
    validate_inputs_first_pass(args)
    if args.nup4:
        try:
            from reportlab.pdfgen.canvas import Canvas
        except ImportError:
            raise HandledException("-n: need reportlab.pdfgen.canvas installed for --nup4")
    pages_to_add, opened_files = read_inputs_to_pagelist(args.input_file, args.page_range)
    validate_inputs_second_pass(args, pages_to_add)
    rotate_pages(args.rotate_page, pages_to_add)
    if args.nup4:
        pad_pages_to_multiple_of_8(pages_to_add)
    normalize_pages_to_A4(pages_to_add)
    crop_at_page = collect_per_page_crops_and_zooms(args.crops, args.symmetry, pages_to_add)
    writer = pypdf.PdfWriter()
    if args.nup4:
        build_nup4_output(writer, pages_to_add, crop_at_page, args.print_margin, args.analyze, Canvas)
    else:
        build_single_pages_output(writer, pages_to_add, crop_at_page)
    for file in opened_files:
        file.close()
    with open(args.output_file, 'wb') as output_file:
        writer.write(output_file)


if __name__ == "__main__":
    try:
        main()
    except HandledException as e:
        handled_error_exit(e)