使用PyPDF2在PDF上去除水印 [英] Watermark Removal on PDF with PyPDF2

问题描述

本节从PyPDF2库中导入必要的类

This Section imports the necessary classes from the PyPDF2 library

from PyPDF2 import PdfFileReader, PdfFileWriter
from PyPDF2.pdf import ContentStream
from PyPDF2.generic import TextStringObject, NameObject
from PyPDF2.utils import b_

>The watermark says SAMPLE on it so I've tried different capitalization cases 
wm_text = 'Sample'
replace_with = ''
>I'm hoping to just replace the SAMPLE watermark with nothing so a space could suffice

> Load PDF into pyPDF
source = PdfFileReader(open('input.pdf', "rb"))
output = PdfFileWriter()

> For each page
for page in range(source.getNumPages()):
    # Get the current page and it's contents
    page = source.getPage(page)
    content_object = page["/Contents"].getObject()
    content = ContentStream(content_object, source)

> Loop over all pdf elements
    for operands, operator in content.operations:

被告知要根据我的PDF文件修改这部分

Was told to adapt this part dependent on my PDF file

        if operator == b_("TJ"):
            text = operands[0][0]
            if isinstance(text, TextStringObject) and text.startswith(wm_text):
                operands[0] = TextStringObject(replace_with)

将修改后的内容设置为页面上的内容对象

Set the modified content as content object on the page

    page.__setitem__(NameObject('/Contents'), content)

将页面添加到输出中

Add the page to the output

    output.addPage(page)

写流 outputStream = open("output.pdf"，"wb") output.write(outputStream)

Write the stream outputStream = open("output.pdf", "wb") output.write(outputStream)

推荐答案

在此处使用问题中的代码是可在Python 3中使用的函数.

Using the code from the question here is a function that works in Python 3.

def removeWatermark(wm_text, inputFile, outputFile):
    from PyPDF4 import PdfFileReader, PdfFileWriter
    from PyPDF4.pdf import ContentStream
    from PyPDF4.generic import TextStringObject, NameObject
    from PyPDF4.utils import b_

    with open(inputFile, "rb") as f:
        source = PdfFileReader(f, "rb")
        output = PdfFileWriter()

        for page in range(source.getNumPages()):
            page = source.getPage(page)
            content_object = page["/Contents"].getObject()
            content = ContentStream(content_object, source)

            for operands, operator in content.operations:
                if operator == b_("Tj"):
                    text = operands[0]

                    if isinstance(text, str) and text.startswith(wm_text):
                        operands[0] = TextStringObject('')

            page.__setitem__(NameObject('/Contents'), content)
            output.addPage(page)

        with open(outputFile, "wb") as outputStream:
            output.write(outputStream)

wm_text = 'wm_text'
inputFile = r'input.pdf'
outputFile = r"output.pdf"
removeWatermark(wm_text, inputFile, outputFile)

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