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

   1 #!/usr/bin/env python3
   2 """
   3 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.
   4 """
   5 import argparse
   6 import io
   7 import os
   8 import sys
   9
  10 def handled_error_exit(msg):
  11     print(f"ERROR: {msg}")
  12     sys.exit(1)
  13
  14 try:
  15     import pypdf
  16 except ImportError:
  17     handled_error_exit("Can't run at all without pypdf installed.")
  18
  19 # some general paper geometry constants
  20 POINTS_PER_CM = 10 * 72 / 25.4
  21 A4_WIDTH = 21 * POINTS_PER_CM
  22 A4_HEIGHT = 29.7 * POINTS_PER_CM
  23 A4 = (A4_WIDTH, A4_HEIGHT)
  24
  25 # constants specifically for --nup4
  26 A4_HALF_WIDTH = A4_WIDTH / 2
  27 A4_HALF_HEIGHT = A4_HEIGHT / 2
  28 CUT_DEPTH = 1.95 * POINTS_PER_CM
  29 CUT_WIDTH = 1.05 * POINTS_PER_CM
  30 MIDDLE_POINT_DEPTH = 0.4 * POINTS_PER_CM
  31 INNER_SPINE_MARGIN_PER_PAGE = 1 * POINTS_PER_CM
  32 QUARTER_SCALE_FACTOR = 0.5
  33 PAGE_ORDER_FOR_NUP4 = (3,0,7,4,1,2,5,6)
  34
  35
  36 class PageCrop:
  37
  38     def __init__(self, left_cm=0, bottom_cm=0, right_cm=0, top_cm=0):
  39         self.left_cm = left_cm
  40         self.bottom_cm = bottom_cm
  41         self.right_cm = right_cm
  42         self.top_cm = top_cm
  43         self.left = float(self.left_cm) * POINTS_PER_CM
  44         self.bottom = float(self.bottom_cm) * POINTS_PER_CM
  45         self.right = float(self.right_cm) * POINTS_PER_CM
  46         self.top = float(self.top_cm) * POINTS_PER_CM
  47         zoom_horizontal = A4_WIDTH / (A4_WIDTH - self.left - self.right)
  48         zoom_vertical = A4_HEIGHT / (A4_HEIGHT - self.bottom - self.top)
  49         if (zoom_horizontal > 1 and zoom_vertical < 1) or (zoom_horizontal < 1 and zoom_vertical > 1):
  50             raise HandledException("-c: crops would create opposing zoom directions")
  51         elif zoom_horizontal + zoom_vertical > 2:
  52             self.zoom = min(zoom_horizontal, zoom_vertical)
  53         else:
  54             self.zoom = max(zoom_horizontal, zoom_vertical)
  55
  56     def __str__(self):
  57         return str(vars(self))
  58
  59     @property
  60     def format_in_cm(self):
  61         return f"left {self.left_cm}cm, bottom {self.bottom_cm}cm, right {self.right_cm}cm, top {self.top_cm}cm"
  62
  63     @property
  64     def remaining_width(self):
  65         return A4_WIDTH - self.left - self.right
  66
  67     @property
  68     def remaining_height(self):
  69         return A4_HEIGHT - self.bottom - self.top
  70
  71     def give_mirror(self):
  72         return PageCrop(left_cm=self.right_cm, bottom_cm=self.bottom_cm, right_cm=self.left_cm, top_cm=self.top_cm)
  73
  74
  75 class Nup4Geometry:
  76
  77     def __init__(self, margin_cm):
  78         self.margin = margin_cm * POINTS_PER_CM
  79         self.shrink_for_margin = (A4_WIDTH - 2 * self.margin)/A4_WIDTH
  80         # NB: We define spine size un-shrunk, but .shrink_for_spine is used with values shrunk for the margin, which we undo here.
  81         spine_part_of_page = (INNER_SPINE_MARGIN_PER_PAGE / A4_HALF_WIDTH) / self.shrink_for_margin
  82         self.shrink_for_spine = 1 - spine_part_of_page
  83
  84
  85 class HandledException(Exception):
  86     pass
  87
  88
  89 def parse_args():
  90     help_epilogue = "See README.txt for detailed usage instructions, command examples, etc."
  91     parser = argparse.ArgumentParser(description=__doc__, epilog=help_epilogue, formatter_class=argparse.RawDescriptionHelpFormatter)
  92     parser.add_argument("-i", "--input_file", action="append", required=True, help="input PDF file")
  93     parser.add_argument("-o", "--output_file", required=True, help="output PDF file")
  94     parser.add_argument("-p", "--page_range", action="append", help="page range, e.g., '2-9' or '3-end' or 'start-14'")
  95     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")
  96     parser.add_argument("-r", "--rotate_page", type=int, action="append", help="rotate page of number by 90° (usable multiple times on same page!)")
  97     parser.add_argument("-s", "--symmetry", action="store_true", help="alternate horizontal crops between odd and even pages")
  98     parser.add_argument("-n", "--nup4", action='store_true', help="puts 4 input pages onto 1 output page, adds binding cut stencil")
  99     parser.add_argument("-a", "--analyze", action="store_true", help="in --nup4, print lines identifying spine, page borders")
 100     parser.add_argument("-m", "--print_margin", type=float, default=0.43, help="print margin for --nup4 in cm (default 0.43)")
 101     return parser.parse_args()
 102
 103
 104 def validate_inputs_first_pass(args):
 105     for filename in args.input_file:
 106         if not os.path.isfile(filename):
 107             raise HandledException(f"-i: {filename} is not a file")
 108         try:
 109             with open(filename, 'rb') as file:
 110                 pypdf.PdfReader(file)
 111         except pypdf.errors.PdfStreamError:
 112             raise HandledException(f"-i: cannot interpret {filename} as PDF file")
 113     if args.page_range:
 114         for p_string in args.page_range:
 115             validate_page_range(p_string, "-p")
 116         if len(args.page_range) > len(args.input_file):
 117             raise HandledException("-p: more --page_range arguments than --input_file arguments")
 118     if args.crops:
 119         for c_string in args.crops:
 120             initial_split = c_string.split(':')
 121             if len(initial_split) > 2:
 122                 raise HandledException(f"-c: cropping string has multiple ':': {c_string}")
 123             page_range, crops = split_crops_string(c_string)
 124             crops = crops.split(",")
 125             if page_range:
 126                 validate_page_range(page_range, "-c")
 127             if len(crops) != 4:
 128                 raise HandledException(f"-c: cropping does not contain exactly three ',': {c_string}")
 129             for crop in crops:
 130                 try:
 131                     float(crop)
 132                 except ValueError:
 133                     raise HandledException(f"-c: non-number crop in: {c_string}")
 134     if args.rotate_page:
 135         for r in args.rotate_page:
 136             try:
 137                 int(r)
 138             except ValueError:
 139                 raise HandledException(f"-r: non-integer value: {r}")
 140             if r < 1:
 141                 raise HandledException(f"-r: value must not be <1: {r}")
 142     try:
 143         float(args.print_margin)
 144     except ValueError:
 145         raise HandledException(f"-m: non-float value: {arg.print_margin}")
 146
 147
 148 def validate_page_range(p_string, err_msg_prefix):
 149     prefix = f"{err_msg_prefix}: page range string"
 150     if '-' not in p_string:
 151         raise HandledException(f"{prefix} lacks '-': {p_string}")
 152     tokens = p_string.split("-")
 153     if len(tokens) > 2:
 154         raise HandledException(f"{prefix} has too many '-': {p_string}")
 155     for i, token in enumerate(tokens):
 156         if token == "":
 157             continue
 158         if i == 0 and token == "start":
 159             continue
 160         if i == 1 and token == "end":
 161             continue
 162         try:
 163             int(token)
 164         except ValueError:
 165             raise HandledException(f"{prefix} carries value neither integer, nor 'start', nor 'end': {p_string}")
 166         if int(token) < 1:
 167             raise HandledException(f"{prefix} carries page number <1: {p_string}")
 168     start = -1
 169     end = -1
 170     try:
 171         start = int(tokens[0])
 172         end = int(tokens[1])
 173     except ValueError:
 174         pass
 175     if start > 0 and end > 0 and start > end:
 176         raise HandledException(f"{prefix} has higher start than end value: {p_string}")
 177
 178
 179 def split_crops_string(c_string):
 180     initial_split = c_string.split(':')
 181     if len(initial_split) > 1:
 182         page_range = initial_split[0]
 183         crops = initial_split[1]
 184     else:
 185         page_range = None
 186         crops = initial_split[0]
 187     return page_range, crops
 188
 189
 190 def parse_page_range(range_string, pages):
 191     start_page = 0
 192     end_page = len(pages)
 193     if range_string:
 194         start, end = range_string.split('-')
 195         if not (len(start) == 0 or start == "start"):
 196             start_page = int(start) - 1
 197         if not (len(end) == 0 or end == "end"):
 198             end_page = int(end)
 199     return start_page, end_page
 200
 201
 202 def read_inputs_to_pagelist(args_input_file, args_page_range):
 203     pages_to_add = []
 204     opened_files = []
 205     new_page_num = 0
 206     for i, input_file in enumerate(args_input_file):
 207         file = open(input_file, 'rb')
 208         opened_files += [file]
 209         reader = pypdf.PdfReader(file)
 210         range_string = None
 211         if args_page_range and len(args_page_range) > i:
 212             range_string = args_page_range[i]
 213         start_page, end_page = parse_page_range(range_string, reader.pages)
 214         if end_page > len(reader.pages):  # no need to test start_page cause start_page > end_page is checked above
 215             raise HandledException(f"-p: page range goes beyond pages of input file: {range_string}")
 216         for old_page_num in range(start_page, end_page):
 217             new_page_num += 1
 218             page = reader.pages[old_page_num]
 219             pages_to_add += [page]
 220             print(f"-i, -p: read in {input_file} page number {old_page_num+1} as new page {new_page_num}")
 221     return pages_to_add, opened_files
 222
 223
 224 def validate_inputs_second_pass(args, pages_to_add):
 225     if args.crops:
 226         for c_string in args.crops:
 227             page_range, _= split_crops_string(c_string)
 228             if page_range:
 229                 start, end = parse_page_range(page_range, pages_to_add)
 230                 if end > len(pages_to_add):
 231                      raise HandledException(f"-c: page range goes beyond number of pages we're building: {page_range}")
 232     if args.rotate_page:
 233         for r in args.rotate_page:
 234             if r > len(pages_to_add):
 235                  raise HandledException(f"-r: page number beyond number of pages we're building: {r}")
 236
 237
 238 def rotate_pages(args_rotate_page, pages_to_add):
 239     if args_rotate_page:
 240         for rotate_page in args_rotate_page:
 241             page = pages_to_add[rotate_page - 1]
 242             page.add_transformation(pypdf.Transformation().translate(tx=-A4_WIDTH/2, ty=-A4_HEIGHT/2))
 243             page.add_transformation(pypdf.Transformation().rotate(-90))
 244             page.add_transformation(pypdf.Transformation().translate(tx=A4_WIDTH/2, ty=A4_HEIGHT/2))
 245             print(f"-r: rotating (by 90°) page {rotate_page}")
 246
 247
 248 def pad_pages_to_multiple_of_8(pages_to_add):
 249     mod_to_8 = len(pages_to_add) % 8
 250     if mod_to_8 > 0:
 251         old_len = len(pages_to_add)
 252         for _ in range(8 - mod_to_8):
 253             new_page = pypdf.PageObject.create_blank_page(width=A4_WIDTH, height=A4_HEIGHT)
 254             pages_to_add += [new_page]
 255         print(f"-n: number of input pages {old_len} not required multiple of 8, padded to {len(pages_to_add)}")
 256
 257
 258 def normalize_pages_to_A4(pages_to_add):
 259     for page in pages_to_add:
 260         if "/Rotate" in page:  # TODO: preserve rotation, but in canvas?
 261             page.rotate(360 - page["/Rotate"])
 262         page.mediabox.left = 0
 263         page.mediabox.bottom = 0
 264         page.mediabox.top = A4_HEIGHT
 265         page.mediabox.right = A4_WIDTH
 266         page.cropbox = page.mediabox
 267
 268
 269 def collect_per_page_crops_and_zooms(args_crops, args_symmetry, pages_to_add):
 270     crop_at_page = [PageCrop()] * len(pages_to_add)
 271     if args_crops:
 272         for c_string in args_crops:
 273             page_range, crops = split_crops_string(c_string)
 274             start_page, end_page = parse_page_range(page_range, pages_to_add)
 275             prefix = "-c, -t" if args_symmetry else "-c"
 276             suffix = " (but alternating left and right crop between even and odd pages)" if args_symmetry else ""
 277             page_crop = PageCrop(*[x for x in crops.split(',')])
 278             print(f"{prefix}: to pages {start_page + 1} to {end_page} applying crop: {page_crop.format_in_cm}{suffix}")
 279             for page_num in range(start_page, end_page):
 280                 if args_symmetry and page_num % 2:
 281                     crop_at_page[page_num] = page_crop.give_mirror()
 282                 else:
 283                     crop_at_page[page_num] = page_crop
 284     return crop_at_page
 285
 286
 287 def build_single_pages_output(writer, pages_to_add, crop_at_page):
 288     print("building 1-input-page-per-output-page book")
 289     odd_page = True
 290     for i, page in enumerate(pages_to_add):
 291         page.add_transformation(pypdf.Transformation().translate(tx=-crop_at_page[i].left, ty=-crop_at_page[i].bottom))
 292         page.add_transformation(pypdf.Transformation().scale(crop_at_page[i].zoom, crop_at_page[i].zoom))
 293         page.mediabox.right = crop_at_page[i].remaining_width * crop_at_page[i].zoom
 294         page.mediabox.top = crop_at_page[i].remaining_height * crop_at_page[i].zoom
 295         writer.add_page(page)
 296         odd_page = not odd_page
 297         print(f"built page number {i+1} (of {len(pages_to_add)})")
 298
 299
 300 def build_nup4_output(writer, pages_to_add, crop_at_page, args_print_margin, args_analyze, canvas_class):
 301     print("-n: building 4-input-pages-per-output-page book")
 302     print(f"-m: applying printable-area margin of {args_print_margin}cm")
 303     if args_analyze:
 304         print("-a: drawing page borders, spine limits")
 305     nup4_geometry = Nup4Geometry(args_print_margin)
 306     pages_to_add, new_i_order = resort_pages_for_nup4(pages_to_add)
 307     nup4_i = 0
 308     page_count = 0
 309     is_front_page = True
 310     for i, page in enumerate(pages_to_add):
 311         if nup4_i == 0:
 312             new_page = pypdf.PageObject.create_blank_page(width=A4_WIDTH, height=A4_HEIGHT)
 313         corrected_i = new_i_order[i]
 314         nup4_inner_page_transform(page, crop_at_page[corrected_i], nup4_geometry, nup4_i)
 315         nup4_outer_page_transform(page, nup4_geometry, nup4_i)
 316         new_page.merge_page(page)
 317         page_count += 1
 318         print(f"merged page number {page_count} (of {len(pages_to_add)})")
 319         nup4_i += 1
 320         if nup4_i > 3:
 321             ornate_nup4(writer, args_analyze, is_front_page, new_page, nup4_geometry, canvas_class)
 322             writer.add_page(new_page)
 323             nup4_i = 0
 324             is_front_page = not is_front_page
 325
 326
 327 def resort_pages_for_nup4(pages_to_add):
 328     new_page_order = []
 329     new_i_order = []
 330     eight_pack = []
 331     i = 0
 332     n_eights = 0
 333     for page in pages_to_add:
 334         if i == 0:
 335             eight_pack = []
 336         eight_pack += [page]
 337         i += 1
 338         if i == 8:
 339             i = 0
 340             for n in PAGE_ORDER_FOR_NUP4:
 341                 new_i_order += [8 * n_eights + n]
 342                 new_page_order += [eight_pack[n]]
 343             n_eights += 1
 344     return new_page_order, new_i_order
 345
 346
 347 def nup4_inner_page_transform(page, crop, nup4_geometry, nup4_i):
 348     page.add_transformation(pypdf.Transformation().translate(ty=(A4_HEIGHT / crop.zoom - (A4_HEIGHT - crop.top))))
 349     if nup4_i == 0 or nup4_i == 2:
 350         page.add_transformation(pypdf.Transformation().translate(tx=-crop.left))
 351     elif nup4_i == 1 or nup4_i == 3:
 352         page.add_transformation(pypdf.Transformation().translate(tx=(A4_WIDTH / crop.zoom - (A4_WIDTH - crop.right))))
 353     page.add_transformation(pypdf.Transformation().scale(crop.zoom * nup4_geometry.shrink_for_spine, crop.zoom * nup4_geometry.shrink_for_spine))
 354     if nup4_i == 2 or nup4_i == 3:
 355         page.add_transformation(pypdf.Transformation().translate(ty=-2*nup4_geometry.margin/nup4_geometry.shrink_for_margin))
 356
 357
 358 def nup4_outer_page_transform(page, nup4_geometry, nup4_i):
 359     page.add_transformation(pypdf.Transformation().translate(ty=(1-nup4_geometry.shrink_for_spine)*A4_HEIGHT))
 360     if nup4_i == 0 or nup4_i == 1:
 361         y_section = A4_HEIGHT
 362         page.mediabox.bottom = A4_HALF_HEIGHT
 363         page.mediabox.top    = A4_HEIGHT
 364     if nup4_i == 2 or nup4_i == 3:
 365         y_section = 0
 366         page.mediabox.bottom = 0
 367         page.mediabox.top  =  A4_HALF_HEIGHT
 368     if nup4_i == 0 or nup4_i == 2:
 369         x_section = 0
 370         page.mediabox.left   = 0
 371         page.mediabox.right  = A4_HALF_WIDTH
 372     if nup4_i == 1 or nup4_i == 3:
 373         page.add_transformation(pypdf.Transformation().translate(tx=(1-nup4_geometry.shrink_for_spine)*A4_WIDTH))
 374         x_section = A4_WIDTH
 375         page.mediabox.left   = A4_HALF_WIDTH
 376         page.mediabox.right  = A4_WIDTH
 377     page.add_transformation(pypdf.Transformation().translate(tx=x_section, ty=y_section))
 378     page.add_transformation(pypdf.Transformation().scale(QUARTER_SCALE_FACTOR, QUARTER_SCALE_FACTOR))
 379
 380
 381 def ornate_nup4(writer, args_analyze, is_front_page, new_page, nup4_geometry, canvas_class):
 382     if args_analyze:
 383         # borders
 384         packet = io.BytesIO()
 385         c = canvas_class(packet, pagesize=A4)
 386         c.setLineWidth(0.1)
 387         c.line(0, A4_HEIGHT, A4_WIDTH, A4_HEIGHT)
 388         c.line(0, A4_HALF_HEIGHT, A4_WIDTH, A4_HALF_HEIGHT)
 389         c.line(0, 0, A4_WIDTH, 0)
 390         c.line(0, A4_HEIGHT, 0, 0)
 391         c.line(A4_HALF_WIDTH, A4_HEIGHT, A4_HALF_WIDTH, 0)
 392         c.line(A4_WIDTH, A4_HEIGHT, A4_WIDTH, 0)
 393         c.save()
 394         new_pdf = pypdf.PdfReader(packet)
 395         new_page.merge_page(new_pdf.pages[0])
 396     printable_offset_x = nup4_geometry.margin
 397     printable_offset_y = nup4_geometry.margin * A4_HEIGHT / A4_WIDTH
 398     new_page.add_transformation(pypdf.Transformation().scale(nup4_geometry.shrink_for_margin, nup4_geometry.shrink_for_margin))
 399     new_page.add_transformation(pypdf.Transformation().translate(tx=printable_offset_x, ty=printable_offset_y))
 400     x_left_spine_limit = A4_HALF_WIDTH * nup4_geometry.shrink_for_spine
 401     x_right_spine_limit = A4_WIDTH - x_left_spine_limit
 402     if args_analyze or is_front_page:
 403         packet = io.BytesIO()
 404         c = canvas_class(packet, pagesize=A4)
 405     if args_analyze:
 406         # spine lines
 407         c.setLineWidth(0.1)
 408         c.line(x_left_spine_limit, A4_HEIGHT, x_left_spine_limit, 0)
 409         c.line(x_right_spine_limit, A4_HEIGHT, x_right_spine_limit, 0)
 410     if is_front_page:
 411         c.setLineWidth(0.2)
 412         draw_cut(c, x_left_spine_limit, (1))
 413         draw_cut(c, x_right_spine_limit, (-1))
 414     if args_analyze or is_front_page:
 415         c.save()
 416         new_pdf = pypdf.PdfReader(packet)
 417         new_page.merge_page(new_pdf.pages[0])
 418
 419
 420 def draw_cut(canvas, x_spine_limit, direction):
 421     outer_start_x = x_spine_limit - 0.5 * CUT_WIDTH * direction
 422     inner_start_x = x_spine_limit + 0.5 * CUT_WIDTH * direction
 423     middle_point_y =  A4_HALF_HEIGHT + MIDDLE_POINT_DEPTH * direction
 424     end_point_y =  A4_HALF_HEIGHT + CUT_DEPTH * direction
 425     canvas.line(inner_start_x, A4_HALF_HEIGHT, x_spine_limit, end_point_y)
 426     canvas.line(x_spine_limit, end_point_y, x_spine_limit, middle_point_y)
 427     canvas.line(x_spine_limit, middle_point_y, outer_start_x, A4_HALF_HEIGHT)
 428
 429
 430 def main():
 431     args = parse_args()
 432     validate_inputs_first_pass(args)
 433     if args.nup4:
 434         try:
 435             from reportlab.pdfgen.canvas import Canvas
 436         except ImportError:
 437             raise HandledException("-n: need reportlab.pdfgen.canvas installed for --nup4")
 438     pages_to_add, opened_files = read_inputs_to_pagelist(args.input_file, args.page_range)
 439     validate_inputs_second_pass(args, pages_to_add)
 440     rotate_pages(args.rotate_page, pages_to_add)
 441     if args.nup4:
 442         pad_pages_to_multiple_of_8(pages_to_add)
 443     normalize_pages_to_A4(pages_to_add)
 444     crop_at_page = collect_per_page_crops_and_zooms(args.crops, args.symmetry, pages_to_add)
 445     writer = pypdf.PdfWriter()
 446     if args.nup4:
 447         build_nup4_output(writer, pages_to_add, crop_at_page, args.print_margin, args.analyze, Canvas)
 448     else:
 449         build_single_pages_output(writer, pages_to_add, crop_at_page)
 450     for file in opened_files:
 451         file.close()
 452     with open(args.output_file, 'wb') as output_file:
 453         writer.write(output_file)
 454
 455
 456 if __name__ == "__main__":
 457     try:
 458         main()
 459     except HandledException as e:
 460         handled_error_exit(e)