PyPdf：将每页一分为二，用空格填充

Question

我有一个 PDF 文件（A4，纵向布局），我想将其中的每一页分成一半的高度。输出文档也应该是A4和纵向布局，但每页的下半部分需要为空白。

我看到了/sf/answers/1102038941/但不明白如何使用 mediaBox 添加空格。

Answer 1

我不太了解 PyPDF2，但我是pdfrw的作者，如果我理解你的问题，pdfrw 当然可以很容易地做你想做的事。我需要更好地记录它，但我有一个预先存在的 unspread.py示例，它可以左右拆分页面，将小报页面分成原始页面。这是该示例的修改版本。此版本将顶部和底部拆分页面，并更改输出页面的大小，使其与输入页面匹配：

#!/usr/bin/env python

'''
usage:   splitv.py my.pdf

Creates splitv.my.pdf

This is similar to unspread.py, in that it creates
a new file that has twice the pages of the old file.

It is different in two ways:

1) It splits pages top and bottom rather than left and right
2) The destination pages are the same size as the source pages,
   and the output is placed at the top.
'''

import sys
import os

from pdfrw import PdfReader, PdfWriter, PageMerge


def splitpage(src):
    ''' Split a page into two (top and bottom)
    '''
    # Yield a result for each half of the page
    for y_pos in (0, 0.5):

        # Create a blank, unsized destination page.
        page = PageMerge()

        # add a portion of the source page to it as
        # a Form XObject.
        page.add(src, viewrect=(0, y_pos, 1, 0.5))

        # By default, the object we created will be
        # at coordinates (0, 0), which is the lower
        # left corner.  To move it up on the page
        # to the top, we simply use its height
        # (which is half the source page height) as
        # its y value.
        page[0].y = page[0].h

        # When we render the page, the media box will
        # encompass (0, 0) and all the objects we have
        # placed on the page, which means the output
        # page will be the same size as the input page.
        yield page.render()


inpfn, = sys.argv[1:]
outfn = 'splitv.' + os.path.basename(inpfn)
writer = PdfWriter()
for page in PdfReader(inpfn).pages:
    writer.addpages(splitpage(page))
writer.write(outfn)