plomlompom.com Git - misc/blob - bookmaker.py

   1 #!/usr/bin/env python3
   2 import pypdf
   3 import argparse
   4 import io
   5 from reportlab.lib.pagesizes import A4
   6 a4_width, a4_height = A4
   7
   8 parser = argparse.ArgumentParser(description="build print-ready book PDF")
   9 parser.add_argument("-i", "--input", dest="input_file", required=True, help="input PDF file")
  10 parser.add_argument("-o", "--output", dest="output_file", required=True, help="output PDF file")
  11 parser.add_argument("-p", "--pages", dest="page_range", help="page range, e.g., '3-end'")
  12 parser.add_argument("-c", "--crop", dest="crop_range", help="crops left, bottom, right, top – e.g., '10,10,10,10'")
  13 parser.add_argument("-n", "--nup4", dest="nup4", action='store_true', help="puts 4 input pages onto 1 output page")
  14 parser.add_argument("-a", "--analyze", dest="analyze", action="store_true", help="print lines identifying spine, page borders")
  15 args = parser.parse_args()
  16
  17 with open(args.input_file, 'rb') as file:
  18     reader = pypdf.PdfReader(file)
  19
  20     # determine page range
  21     start_page = 0
  22     end_page = len(reader.pages)
  23     if args.page_range:
  24         start, end = args.page_range.split('-')
  25         if not (len(start) == 0 or start == "start"):
  26             start_page = int(start) - 1
  27         if not (len(end) == 0 or end == "end"):
  28             end_page = int(end)
  29     pages_to_add = []
  30     for page_num in range(start_page, end_page):
  31         page = reader.pages[page_num]
  32         pages_to_add += [page]
  33         print("read in page number", page_num+1)
  34
  35     # normalize all pages to A4
  36     for page_num in range(start_page, end_page):
  37         page = reader.pages[page_num]
  38         page.mediabox.left = 0
  39         page.mediabox.bottom = 0
  40         page.mediabox.top = a4_height
  41         page.mediabox.right = a4_width
  42         page.cropbox = page.mediabox
  43
  44     # determine page crop
  45     crop_left, crop_bottom, crop_right, crop_top = 0, 0, 0, 0
  46     if args.crop_range:
  47         crop_left, crop_bottom, crop_right, crop_top = [float(x) for x in  args.crop_range.split(',')]
  48     cropped_width  = a4_width - crop_left - crop_right
  49     cropped_height = a4_height - crop_bottom - crop_top
  50     zoom = 1
  51     if args.crop_range:
  52         zoom_horizontal = a4_width / (a4_width - crop_left - crop_right)
  53         zoom_vertical = a4_height / (a4_height - crop_bottom - crop_top)
  54         if (zoom_horizontal > 1 and zoom_vertical < 1) or (zoom_horizontal < 1 and zoom_vertical > 1):
  55             print("Error: opposing zooms.")
  56             exit(1)
  57         elif zoom_horizontal + zoom_vertical > 2:
  58             zoom = min(zoom_horizontal, zoom_vertical)
  59         else:
  60             zoom = max(zoom_horizontal, zoom_vertical)
  61
  62     writer = pypdf.PdfWriter()
  63     if not args.nup4:
  64         for page in pages_to_add:
  65             page.add_transformation(pypdf.Transformation().translate(tx=-crop_left, ty=-crop_bottom))
  66             page.add_transformation(pypdf.Transformation().scale(zoom, zoom))
  67             page.mediabox.right = cropped_width * zoom
  68             page.mediabox.top = cropped_height * zoom
  69             writer.add_page(page)
  70     else:
  71         n_pages_per_axis = 2
  72         points_per_mm = 2.83465
  73         printable_margin = 4.3 * points_per_mm
  74         printable_scale = (a4_width - 2*printable_margin)/a4_width
  75         spine_limit = 10 * points_per_mm
  76         half_width = a4_width / n_pages_per_axis
  77         half_height = a4_height / n_pages_per_axis
  78         section_scale_factor = 1 / n_pages_per_axis
  79         spine_part_of_page = (spine_limit / half_width) / printable_scale
  80         bonus_shrink_factor = 1 - spine_part_of_page
  81         new_page_order = []
  82         eight_pack = []
  83         mod_to_8 = len(pages_to_add) % 8
  84         if mod_to_8 > 0:
  85             for _ in range(8 - mod_to_8):
  86                 new_page = pypdf.PageObject.create_blank_page(width=a4_width, height=a4_height)
  87                 pages_to_add += [new_page]
  88         i = 0
  89         for page in pages_to_add:
  90             if i == 0:
  91                 eight_pack = []
  92             eight_pack += [page]
  93             i += 1
  94             if i == 8:
  95                 i = 0
  96                 new_page_order += [eight_pack[3]]  # page front, upper left
  97                 new_page_order += [eight_pack[0]]  # page front, upper right
  98                 new_page_order += [eight_pack[7]]  # page front, lower left
  99                 new_page_order += [eight_pack[4]]  # page front, lower right
 100                 new_page_order += [eight_pack[1]]  # page back, upper left
 101                 new_page_order += [eight_pack[2]]  # page back, upper right
 102                 new_page_order += [eight_pack[5]]  # page back, lower left
 103                 new_page_order += [eight_pack[6]]  # page back, lower right
 104         i = 0
 105         page_count = 0
 106         front_page = True
 107         for page in new_page_order:
 108             if i == 0:
 109                 new_page = pypdf.PageObject.create_blank_page(width=a4_width, height=a4_height)
 110
 111             # in-section transformations: align pages on top, left-hand pages to left, right-hand to right
 112             page.add_transformation(pypdf.Transformation().translate(ty=(a4_height / zoom - (a4_height - crop_top))))
 113             if i == 0 or i == 2:
 114                 page.add_transformation(pypdf.Transformation().translate(tx=-crop_left))
 115             elif i == 1 or i == 3:
 116                 page.add_transformation(pypdf.Transformation().translate(tx=(a4_width / zoom - (a4_width - crop_right))))
 117             page.add_transformation(pypdf.Transformation().scale(zoom * bonus_shrink_factor, zoom * bonus_shrink_factor))
 118             if i == 2 or i == 3:
 119                 page.add_transformation(pypdf.Transformation().translate(ty=-2*printable_margin/printable_scale))
 120
 121             # outer section transformations
 122             page.add_transformation(pypdf.Transformation().translate(ty=(1-bonus_shrink_factor)*a4_height))
 123             if i == 0 or i == 1:
 124                 y_section = a4_height
 125                 page.mediabox.bottom = half_height
 126                 page.mediabox.top    = a4_height
 127             if i == 2 or i == 3:
 128                 y_section = 0
 129                 page.mediabox.bottom = 0
 130                 page.mediabox.top  =   half_height
 131             if i == 0 or i == 2:
 132                 x_section = 0
 133                 page.mediabox.left   = 0
 134                 page.mediabox.right  = half_width
 135             if i == 1 or i == 3:
 136                 page.add_transformation(pypdf.Transformation().translate(tx=(1-bonus_shrink_factor)*a4_width))
 137                 x_section = a4_width
 138                 page.mediabox.left   = half_width
 139                 page.mediabox.right  = a4_width
 140             page.add_transformation(pypdf.Transformation().translate(tx=x_section, ty=y_section))
 141             page.add_transformation(pypdf.Transformation().scale(section_scale_factor, section_scale_factor))
 142             new_page.merge_page(page)
 143             page_count += 1
 144             print("merged page number", page_count)
 145             i += 1
 146             if i > 3:
 147                 from reportlab.pdfgen import canvas
 148                 if args.analyze:
 149                     # borders
 150                     packet = io.BytesIO()
 151                     c = canvas.Canvas(packet, pagesize=A4)
 152                     c.setLineWidth(0.1)
 153                     c.line(0, a4_height, a4_width, a4_height)
 154                     c.line(0, half_height, a4_width, half_height)
 155                     c.line(0, 0, a4_width, 0)
 156                     c.line(0, a4_height, 0, 0)
 157                     c.line(half_width, a4_height, half_width, 0)
 158                     c.line(a4_width, a4_height, a4_width, 0)
 159                     c.save()
 160                     new_pdf = pypdf.PdfReader(packet)
 161                     new_page.merge_page(new_pdf.pages[0])
 162                 printable_offset_x = printable_margin
 163                 printable_offset_y = printable_margin * a4_height / a4_width
 164                 new_page.add_transformation(pypdf.Transformation().scale(printable_scale, printable_scale))
 165                 new_page.add_transformation(pypdf.Transformation().translate(tx=printable_offset_x, ty=printable_offset_y))
 166                 x_left_spine_limit = half_width * bonus_shrink_factor
 167                 x_right_spine_limit = a4_width - x_left_spine_limit
 168                 if args.analyze or front_page:
 169                     packet = io.BytesIO()
 170                     c = canvas.Canvas(packet, pagesize=A4)
 171                 if args.analyze:
 172                     # # spine lines
 173                     c.setLineWidth(0.1)
 174                     c.line(x_left_spine_limit, a4_height, x_left_spine_limit, 0)
 175                     c.line(x_right_spine_limit, a4_height, x_right_spine_limit, 0)
 176                 if front_page:
 177                     c.setLineWidth(0.2)
 178                     cut_depth = 19.5 * points_per_mm
 179                     cut_width = 10.5 * points_per_mm
 180                     middle_point_depth = 4 * points_per_mm
 181
 182                     start_up_left_left_x = x_left_spine_limit - 0.5 * cut_width
 183                     start_up_left_right_x = x_left_spine_limit + 0.5 * cut_width
 184                     middle_point_up_left_y = half_height + middle_point_depth
 185                     end_point_up_left_y = half_height + cut_depth
 186                     c.line(start_up_left_right_x, half_height, x_left_spine_limit, end_point_up_left_y)
 187                     c.line(x_left_spine_limit, end_point_up_left_y, x_left_spine_limit, middle_point_up_left_y)
 188                     c.line(x_left_spine_limit, middle_point_up_left_y, start_up_left_left_x, half_height)
 189
 190                     start_down_right_left_x = x_right_spine_limit - 0.5 * cut_width
 191                     start_down_right_right_x = x_right_spine_limit + 0.5 * cut_width
 192                     middle_point_down_right_y = half_height - middle_point_depth
 193                     end_point_down_right_y = half_height - cut_depth
 194                     c.line(start_down_right_left_x, half_height, x_right_spine_limit, end_point_down_right_y)
 195                     c.line(x_right_spine_limit, end_point_down_right_y, x_right_spine_limit, middle_point_down_right_y)
 196                     c.line(x_right_spine_limit, middle_point_down_right_y, start_down_right_right_x, half_height)
 197
 198                 if args.analyze or front_page:
 199                     c.save()
 200                     # packet.seek(0)
 201                     new_pdf = pypdf.PdfReader(packet)
 202                     new_page.merge_page(new_pdf.pages[0])
 203                 writer.add_page(new_page)
 204                 i = 0
 205                 front_page = not front_page
 206
 207     with open(args.output_file, 'wb') as output_file:
 208         writer.write(output_file)