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 parser.add_argument("-t", "--symmetry", dest="symmetry", action="store_true", help="alternate horizontal crops between odd and even pages")
  16 args = parser.parse_args()
  17
  18 with open(args.input_file, 'rb') as file:
  19     reader = pypdf.PdfReader(file)
  20
  21     # determine page range
  22     start_page = 0
  23     end_page = len(reader.pages)
  24     if args.page_range:
  25         start, end = args.page_range.split('-')
  26         if not (len(start) == 0 or start == "start"):
  27             start_page = int(start) - 1
  28         if not (len(end) == 0 or end == "end"):
  29             end_page = int(end)
  30     pages_to_add = []
  31     for page_num in range(start_page, end_page):
  32         page = reader.pages[page_num]
  33         pages_to_add += [page]
  34         print("read in page number", page_num+1)
  35
  36     # normalize all pages to A4
  37     for page_num in range(start_page, end_page):
  38         page = reader.pages[page_num]
  39         page.mediabox.left = 0
  40         page.mediabox.bottom = 0
  41         page.mediabox.top = a4_height
  42         page.mediabox.right = a4_width
  43         page.cropbox = page.mediabox
  44
  45     # determine page crop
  46     crop_left, crop_bottom, crop_right, crop_top = 0, 0, 0, 0
  47     if args.crop_range:
  48         crop_left, crop_bottom, crop_right, crop_top = [float(x) for x in  args.crop_range.split(',')]
  49     cropped_width  = a4_width - crop_left - crop_right
  50     cropped_height = a4_height - crop_bottom - crop_top
  51     zoom = 1
  52     if args.crop_range:
  53         zoom_horizontal = a4_width / (a4_width - crop_left - crop_right)
  54         zoom_vertical = a4_height / (a4_height - crop_bottom - crop_top)
  55         if (zoom_horizontal > 1 and zoom_vertical < 1) or (zoom_horizontal < 1 and zoom_vertical > 1):
  56             print("Error: opposing zooms.")
  57             exit(1)
  58         elif zoom_horizontal + zoom_vertical > 2:
  59             zoom = min(zoom_horizontal, zoom_vertical)
  60         else:
  61             zoom = max(zoom_horizontal, zoom_vertical)
  62
  63     writer = pypdf.PdfWriter()
  64     if not args.nup4:
  65         odd_page = True
  66         for page in pages_to_add:
  67             if args.symmetry and odd_page:
  68                 page.add_transformation(pypdf.Transformation().translate(tx=-crop_left, ty=-crop_bottom))
  69             else:
  70                 page.add_transformation(pypdf.Transformation().translate(tx=-crop_right, ty=-crop_bottom))
  71             page.add_transformation(pypdf.Transformation().scale(zoom, zoom))
  72             page.mediabox.right = cropped_width * zoom
  73             page.mediabox.top = cropped_height * zoom
  74             writer.add_page(page)
  75             odd_page = not odd_page
  76     else:
  77         n_pages_per_axis = 2
  78         points_per_mm = 2.83465
  79         printable_margin = 4.3 * points_per_mm
  80         printable_scale = (a4_width - 2*printable_margin)/a4_width
  81         spine_limit = 10 * points_per_mm
  82         half_width = a4_width / n_pages_per_axis
  83         half_height = a4_height / n_pages_per_axis
  84         section_scale_factor = 1 / n_pages_per_axis
  85         spine_part_of_page = (spine_limit / half_width) / printable_scale
  86         bonus_shrink_factor = 1 - spine_part_of_page
  87         new_page_order = []
  88         eight_pack = []
  89         mod_to_8 = len(pages_to_add) % 8
  90         if mod_to_8 > 0:
  91             for _ in range(8 - mod_to_8):
  92                 new_page = pypdf.PageObject.create_blank_page(width=a4_width, height=a4_height)
  93                 pages_to_add += [new_page]
  94         i = 0
  95         for page in pages_to_add:
  96             if i == 0:
  97                 eight_pack = []
  98             eight_pack += [page]
  99             i += 1
 100             if i == 8:
 101                 i = 0
 102                 new_page_order += [eight_pack[3]]  # page front, upper left
 103                 new_page_order += [eight_pack[0]]  # page front, upper right
 104                 new_page_order += [eight_pack[7]]  # page front, lower left
 105                 new_page_order += [eight_pack[4]]  # page front, lower right
 106                 new_page_order += [eight_pack[1]]  # page back, upper left
 107                 new_page_order += [eight_pack[2]]  # page back, upper right
 108                 new_page_order += [eight_pack[5]]  # page back, lower left
 109                 new_page_order += [eight_pack[6]]  # page back, lower right
 110         i = 0
 111         page_count = 0
 112         front_page = True
 113         for page in new_page_order:
 114             if i == 0:
 115                 new_page = pypdf.PageObject.create_blank_page(width=a4_width, height=a4_height)
 116
 117             # in-section transformations: align pages on top, left-hand pages to left, right-hand to right
 118             page.add_transformation(pypdf.Transformation().translate(ty=(a4_height / zoom - (a4_height - crop_top))))
 119             if i == 0 or i == 2:
 120                 if args.symmetry:
 121                     page.add_transformation(pypdf.Transformation().translate(tx=-crop_right))
 122                 else:
 123                     page.add_transformation(pypdf.Transformation().translate(tx=-crop_left))
 124             elif i == 1 or i == 3:
 125                 page.add_transformation(pypdf.Transformation().translate(tx=(a4_width / zoom - (a4_width - crop_right))))
 126             page.add_transformation(pypdf.Transformation().scale(zoom * bonus_shrink_factor, zoom * bonus_shrink_factor))
 127             if i == 2 or i == 3:
 128                 page.add_transformation(pypdf.Transformation().translate(ty=-2*printable_margin/printable_scale))
 129
 130             # outer section transformations
 131             page.add_transformation(pypdf.Transformation().translate(ty=(1-bonus_shrink_factor)*a4_height))
 132             if i == 0 or i == 1:
 133                 y_section = a4_height
 134                 page.mediabox.bottom = half_height
 135                 page.mediabox.top    = a4_height
 136             if i == 2 or i == 3:
 137                 y_section = 0
 138                 page.mediabox.bottom = 0
 139                 page.mediabox.top  =   half_height
 140             if i == 0 or i == 2:
 141                 x_section = 0
 142                 page.mediabox.left   = 0
 143                 page.mediabox.right  = half_width
 144             if i == 1 or i == 3:
 145                 page.add_transformation(pypdf.Transformation().translate(tx=(1-bonus_shrink_factor)*a4_width))
 146                 x_section = a4_width
 147                 page.mediabox.left   = half_width
 148                 page.mediabox.right  = a4_width
 149             page.add_transformation(pypdf.Transformation().translate(tx=x_section, ty=y_section))
 150             page.add_transformation(pypdf.Transformation().scale(section_scale_factor, section_scale_factor))
 151             new_page.merge_page(page)
 152             page_count += 1
 153             print("merged page number", page_count)
 154             i += 1
 155             if i > 3:
 156                 from reportlab.pdfgen import canvas
 157                 if args.analyze:
 158                     # borders
 159                     packet = io.BytesIO()
 160                     c = canvas.Canvas(packet, pagesize=A4)
 161                     c.setLineWidth(0.1)
 162                     c.line(0, a4_height, a4_width, a4_height)
 163                     c.line(0, half_height, a4_width, half_height)
 164                     c.line(0, 0, a4_width, 0)
 165                     c.line(0, a4_height, 0, 0)
 166                     c.line(half_width, a4_height, half_width, 0)
 167                     c.line(a4_width, a4_height, a4_width, 0)
 168                     c.save()
 169                     new_pdf = pypdf.PdfReader(packet)
 170                     new_page.merge_page(new_pdf.pages[0])
 171                 printable_offset_x = printable_margin
 172                 printable_offset_y = printable_margin * a4_height / a4_width
 173                 new_page.add_transformation(pypdf.Transformation().scale(printable_scale, printable_scale))
 174                 new_page.add_transformation(pypdf.Transformation().translate(tx=printable_offset_x, ty=printable_offset_y))
 175                 x_left_spine_limit = half_width * bonus_shrink_factor
 176                 x_right_spine_limit = a4_width - x_left_spine_limit
 177                 if args.analyze or front_page:
 178                     packet = io.BytesIO()
 179                     c = canvas.Canvas(packet, pagesize=A4)
 180                 if args.analyze:
 181                     # # spine lines
 182                     c.setLineWidth(0.1)
 183                     c.line(x_left_spine_limit, a4_height, x_left_spine_limit, 0)
 184                     c.line(x_right_spine_limit, a4_height, x_right_spine_limit, 0)
 185                 if front_page:
 186                     c.setLineWidth(0.2)
 187                     cut_depth = 19.5 * points_per_mm
 188                     cut_width = 10.5 * points_per_mm
 189                     middle_point_depth = 4 * points_per_mm
 190
 191                     start_up_left_left_x = x_left_spine_limit - 0.5 * cut_width
 192                     start_up_left_right_x = x_left_spine_limit + 0.5 * cut_width
 193                     middle_point_up_left_y = half_height + middle_point_depth
 194                     end_point_up_left_y = half_height + cut_depth
 195                     c.line(start_up_left_right_x, half_height, x_left_spine_limit, end_point_up_left_y)
 196                     c.line(x_left_spine_limit, end_point_up_left_y, x_left_spine_limit, middle_point_up_left_y)
 197                     c.line(x_left_spine_limit, middle_point_up_left_y, start_up_left_left_x, half_height)
 198
 199                     start_down_right_left_x = x_right_spine_limit - 0.5 * cut_width
 200                     start_down_right_right_x = x_right_spine_limit + 0.5 * cut_width
 201                     middle_point_down_right_y = half_height - middle_point_depth
 202                     end_point_down_right_y = half_height - cut_depth
 203                     c.line(start_down_right_left_x, half_height, x_right_spine_limit, end_point_down_right_y)
 204                     c.line(x_right_spine_limit, end_point_down_right_y, x_right_spine_limit, middle_point_down_right_y)
 205                     c.line(x_right_spine_limit, middle_point_down_right_y, start_down_right_right_x, half_height)
 206
 207                 if args.analyze or front_page:
 208                     c.save()
 209                     # packet.seek(0)
 210                     new_pdf = pypdf.PdfReader(packet)
 211                     new_page.merge_page(new_pdf.pages[0])
 212                 writer.add_page(new_page)
 213                 i = 0
 214                 front_page = not front_page
 215
 216     with open(args.output_file, 'wb') as output_file:
 217         writer.write(output_file)