--- /dev/null
+#!/usr/bin/env python3
+import pypdf
+import argparse
+import io
+from reportlab.lib.pagesizes import A4
+a4_width, a4_height = A4
+
+parser = argparse.ArgumentParser(description="build print-ready book PDF")
+parser.add_argument("-i", "--input", dest="input_file", required=True, help="input PDF file")
+parser.add_argument("-o", "--output", dest="output_file", required=True, help="output PDF file")
+parser.add_argument("-p", "--pages", dest="page_range", help="page range, e.g., '3-end'")
+parser.add_argument("-c", "--crop", dest="crop_range", help="crops left, bottom, right, top – e.g., '10,10,10,10'")
+parser.add_argument("-n", "--nup4", dest="nup4", action='store_true', help="puts 4 input pages onto 1 output page")
+parser.add_argument("-a", "--analyze", dest="analyze", action="store_true", help="print lines identifying spine, page borders")
+args = parser.parse_args()
+
+with open(args.input_file, 'rb') as file:
+ reader = pypdf.PdfReader(file)
+
+ # determine page range
+ start_page = 0
+ end_page = len(reader.pages)
+ if args.page_range:
+ start, end = args.page_range.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)
+ pages_to_add = []
+ for page_num in range(start_page, end_page):
+ page = reader.pages[page_num]
+ pages_to_add += [page]
+ print("read in page number", page_num+1)
+
+ # normalize all pages to A4
+ for page_num in range(start_page, end_page):
+ page = reader.pages[page_num]
+ page.mediabox.left = 0
+ page.mediabox.bottom = 0
+ page.mediabox.top = a4_height
+ page.mediabox.right = a4_width
+ page.cropbox = page.mediabox
+
+ # determine page crop
+ crop_left, crop_bottom, crop_right, crop_top = 0, 0, 0, 0
+ if args.crop_range:
+ crop_left, crop_bottom, crop_right, crop_top = [float(x) for x in args.crop_range.split(',')]
+ cropped_width = a4_width - crop_left - crop_right
+ cropped_height = a4_height - crop_bottom - crop_top
+ zoom = 1
+ if args.crop_range:
+ zoom_horizontal = a4_width / (a4_width - crop_left - crop_right)
+ zoom_vertical = a4_height / (a4_height - crop_bottom - crop_top)
+ if (zoom_horizontal > 1 and zoom_vertical < 1) or (zoom_horizontal < 1 and zoom_vertical > 1):
+ print("Error: opposing zooms.")
+ exit(1)
+ elif zoom_horizontal + zoom_vertical > 2:
+ zoom = min(zoom_horizontal, zoom_vertical)
+ else:
+ zoom = max(zoom_horizontal, zoom_vertical)
+
+ writer = pypdf.PdfWriter()
+ if not args.nup4:
+ for page in pages_to_add:
+ page.add_transformation(pypdf.Transformation().translate(tx=-crop_left, ty=-crop_bottom))
+ page.add_transformation(pypdf.Transformation().scale(zoom, zoom))
+ page.mediabox.right = cropped_width * zoom
+ page.mediabox.top = cropped_height * zoom
+ writer.add_page(page)
+ else:
+ n_pages_per_axis = 2
+ points_per_mm = 2.83465
+ printable_margin = 4.3 * points_per_mm
+ printable_scale = (a4_width - 2*printable_margin)/a4_width
+ spine_limit = 10 * points_per_mm
+ half_width = a4_width / n_pages_per_axis
+ half_height = a4_height / n_pages_per_axis
+ section_scale_factor = 1 / n_pages_per_axis
+ spine_part_of_page = (spine_limit / half_width) / printable_scale
+ bonus_shrink_factor = 1 - spine_part_of_page
+ new_page_order = []
+ eight_pack = []
+ mod_to_8 = len(pages_to_add) % 8
+ if mod_to_8 > 0:
+ 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]
+ i = 0
+ for page in pages_to_add:
+ if i == 0:
+ eight_pack = []
+ eight_pack += [page]
+ i += 1
+ if i == 8:
+ i = 0
+ new_page_order += [eight_pack[3]] # page front, upper left
+ new_page_order += [eight_pack[0]] # page front, upper right
+ new_page_order += [eight_pack[7]] # page front, lower left
+ new_page_order += [eight_pack[4]] # page front, lower right
+ new_page_order += [eight_pack[1]] # page back, upper left
+ new_page_order += [eight_pack[2]] # page back, upper right
+ new_page_order += [eight_pack[5]] # page back, lower left
+ new_page_order += [eight_pack[6]] # page back, lower right
+ i = 0
+ page_count = 0
+ front_page = True
+ for page in new_page_order:
+ if i == 0:
+ new_page = pypdf.PageObject.create_blank_page(width=a4_width, height=a4_height)
+
+ # in-section transformations: align pages on top, left-hand pages to left, right-hand to right
+ page.add_transformation(pypdf.Transformation().translate(ty=(a4_height / zoom - (a4_height - crop_top))))
+ if i == 0 or i == 2:
+ page.add_transformation(pypdf.Transformation().translate(tx=-crop_left))
+ elif i == 1 or i == 3:
+ page.add_transformation(pypdf.Transformation().translate(tx=(a4_width / zoom - (a4_width - crop_right))))
+ page.add_transformation(pypdf.Transformation().scale(zoom * bonus_shrink_factor, zoom * bonus_shrink_factor))
+ if i == 2 or i == 3:
+ page.add_transformation(pypdf.Transformation().translate(ty=-2*printable_margin/printable_scale))
+
+ # outer section transformations
+ page.add_transformation(pypdf.Transformation().translate(ty=(1-bonus_shrink_factor)*a4_height))
+ if i == 0 or i == 1:
+ y_section = a4_height
+ page.mediabox.bottom = half_height
+ page.mediabox.top = a4_height
+ if i == 2 or i == 3:
+ y_section = 0
+ page.mediabox.bottom = 0
+ page.mediabox.top = half_height
+ if i == 0 or i == 2:
+ x_section = 0
+ page.mediabox.left = 0
+ page.mediabox.right = half_width
+ if i == 1 or i == 3:
+ page.add_transformation(pypdf.Transformation().translate(tx=(1-bonus_shrink_factor)*a4_width))
+ x_section = a4_width
+ page.mediabox.left = 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(section_scale_factor, section_scale_factor))
+ new_page.merge_page(page)
+ page_count += 1
+ print("merged page number", page_count)
+ i += 1
+ if i > 3:
+ from reportlab.pdfgen import canvas
+ if args.analyze:
+ # borders
+ packet = io.BytesIO()
+ c = canvas.Canvas(packet, pagesize=A4)
+ c.setLineWidth(0.1)
+ c.line(0, a4_height, a4_width, a4_height)
+ c.line(0, half_height, a4_width, half_height)
+ c.line(0, 0, a4_width, 0)
+ c.line(0, a4_height, 0, 0)
+ c.line(half_width, a4_height, 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 = printable_margin
+ printable_offset_y = printable_margin * a4_height / a4_width
+ new_page.add_transformation(pypdf.Transformation().scale(printable_scale, printable_scale))
+ new_page.add_transformation(pypdf.Transformation().translate(tx=printable_offset_x, ty=printable_offset_y))
+ x_left_spine_limit = half_width * bonus_shrink_factor
+ x_right_spine_limit = a4_width - x_left_spine_limit
+ if args.analyze or front_page:
+ packet = io.BytesIO()
+ c = canvas.Canvas(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 front_page:
+ c.setLineWidth(0.2)
+ cut_depth = 19.5 * points_per_mm
+ cut_width = 10.5 * points_per_mm
+ middle_point_depth = 4 * points_per_mm
+
+ start_up_left_left_x = x_left_spine_limit - 0.5 * cut_width
+ start_up_left_right_x = x_left_spine_limit + 0.5 * cut_width
+ middle_point_up_left_y = half_height + middle_point_depth
+ end_point_up_left_y = half_height + cut_depth
+ c.line(start_up_left_right_x, half_height, x_left_spine_limit, end_point_up_left_y)
+ c.line(x_left_spine_limit, end_point_up_left_y, x_left_spine_limit, middle_point_up_left_y)
+ c.line(x_left_spine_limit, middle_point_up_left_y, start_up_left_left_x, half_height)
+
+ start_down_right_left_x = x_right_spine_limit - 0.5 * cut_width
+ start_down_right_right_x = x_right_spine_limit + 0.5 * cut_width
+ middle_point_down_right_y = half_height - middle_point_depth
+ end_point_down_right_y = half_height - cut_depth
+ c.line(start_down_right_left_x, half_height, x_right_spine_limit, end_point_down_right_y)
+ c.line(x_right_spine_limit, end_point_down_right_y, x_right_spine_limit, middle_point_down_right_y)
+ c.line(x_right_spine_limit, middle_point_down_right_y, start_down_right_right_x, half_height)
+
+ if args.analyze or front_page:
+ c.save()
+ # packet.seek(0)
+ new_pdf = pypdf.PdfReader(packet)
+ new_page.merge_page(new_pdf.pages[0])
+ writer.add_page(new_page)
+ i = 0
+ front_page = not front_page
+
+ with open(args.output_file, 'wb') as output_file:
+ writer.write(output_file)