实际页码可能因为pdf中没包含空白页而需要中途校正，另附简化后无gui脚本

[vincentaxhe]

有很多书新章是在奇数页的，上一章最后页可能会成空白，但扫描后的pdf没有包含进空白页，就造成ocr目录后的页码加上个数字还是会有错位，错位还会变大，只有写入bookmark后尝试点击才会发现是否有错位。 解决方式也简单，就是在有错位的地方，加上数字校正，在校正变化的地方加上新数字，这样不用却在目录文件中更新很多数字，还与实际目录中页码对应。我简化成脚本中增加了该功能。

#!/bin/python
import os
import re
import sys
from collections import defaultdict
from pypdf import PdfWriter, PdfReader, PageObject
from pypdf.generic import Destination

class Pdf(object):
    def __init__(self, path):
        self.path = path
        self.reader = PdfReader(open(path, "rb"), strict=False)
        self.pages_num = self._get_pages_num(self.reader.pages)
        self._writer = None

    @property
    def _new_path(self):
        name, ext = os.path.splitext(self.path)
        return name + '_new' + ext

    @property
    def writer(self):
        if not self._writer:
            writer = PdfWriter()
            self.copy_reader_to_writer(self.reader, writer)
            writer._root_object.pop("/Outlines", None)
            self._writer = writer
        return self._writer

    @staticmethod
    def copy_reader_to_writer(reader, writer):
        try:
            writer.append(reader, import_outline=False)
        except Exception as e:
            print("Copy pdf failed, {}, try to exclude /Annots and /B".format(e))
            try:
                writer.append(reader, import_outline=False, excluded_fields=["/Annots", "/B"])
            except Exception as e:
                print("Copy pdf failed again, {}, try to use append_pages_from_reader".format(e))
                writer.append_pages_from_reader(reader)

    @staticmethod
    def _get_pages_num(pages):
        pages_num = {}
        for page in pages:
            try:
                if isinstance(page, PageObject):
                    pages_num[page.indirect_ref.idnum] = page.page_number
                else:
                    print("Unknown page type {} for {}".format(type(page), page.page_number))
            except Exception as e:
                print(e)
        return pages_num

    def _outlines_to_bookmarks(self, outlines, current_level=0):
        index_list = []
        for o in outlines:
            if isinstance(o, Destination):
                try:
                    idnum = o.page if isinstance(o.page, int) else o.page.idnum
                    title = "\t" * current_level + o.title.strip()
                    page_num = self.pages_num[idnum] + 1
                    index_list.append("{title}\t{page_num}".format(title=title, page_num=page_num))
                except Exception as e:
                    print(e)
            elif isinstance(o, list):
                index_list += self._outlines_to_bookmarks(o, current_level + 1)
            else:
                print("Unknown outline type: {} in {}".format(type(o), o))
                continue
        return index_list

    def exist_bookmarks(self):
        return self._outlines_to_bookmarks(self.reader.outline)

    def add_bookmark(self, title, pagenum, parent=None):
        return self.writer.add_outline_item(title, pagenum, parent=parent)

    def save_pdf(self):
        if os.path.exists(self._new_path):
            os.remove(self._new_path)
        with open(self._new_path, 'wb') as out:
            self.writer.write(out)
        return self._new_path

def _add_bookmark(pdf, index_dict):
    if not index_dict:
        return None
    m = max(index_dict.keys())
    parent_dict = {}
    max_page_num = len(pdf.writer.pages) - 1
    for i in range(m+1):
        value = index_dict[i]
        inobject = pdf.add_bookmark(value.get('title', ''),
                                    min(value.get('pagenum', 1) - 1, max_page_num),
                                    parent_dict.get(value.get('parent')))
        parent_dict[i] = inobject

def add_bookmark(path, index_dict):
    pdf = Pdf(path)
    _add_bookmark(pdf, index_dict)
    return pdf.save_pdf()

def get_bookmarks(path):
    if not path:
        return []
    try:
        return Pdf(path).exist_bookmarks()
    except Exception as e:
        print("Read pdf %s failed! %s" % (path, e))
        return []

def toc_reader(path, gap):
    pattern = re.compile(r'^(\t*)([^\t]+)\t(-?\d+)(?:\t([-+]\d+))?$')
    tocdict = {}
    levels = defaultdict(list)
    lastpagenum = 0
    fix = 0
    with open(path, 'r') as toc:
        for line, item in enumerate(toc):
            content = pattern.search(item)
            assert content, f"line {line}:{item} line ill-formatted"
            indent, title, pagenum, fixpagenum = content.group(1, 2, 3, 4)
            if fixpagenum:
                fix = int(fixpagenum)
            pagenum = int(pagenum) + int(gap) + fix
            assert pagenum >= lastpagenum, f"line {line}:{item} pagenum wrong"
            tocdict[line] = {'title': title, 'pagenum': pagenum}
            levels[len(indent)].append(line)
            if len(indent) > 0:
                tocdict[line]['parent'] = levels[len(indent) - 1][-1]
            lastpagenum = pagenum
    return tocdict
if __name__ == '__main__':
    args = len(sys.argv)
    if args == 2:
        file = sys.argv[1]
        toclist = get_bookmarks(file)
        for item in toclist:
            print(item)
    elif args == 4:
        file, toc, gap = sys.argv[1:]
        tocdict = toc_reader(toc, gap)
        add_bookmark(file, tocdict)

根据不是很近的api更新的，页码严格增加。 pdfbookmark.py xxx.pdf 输出toc pdfbookmark.py xxx.pdf tocfile 10 写入toc，生成新pdf 我自己觉得用脚本更方便，不敢藏私，借用了api才很好用。

[chroming]

感谢提供优化代码