创建需要的水印模板
wps创建
输出pdf
水印pdf
实现步骤
安装依赖
pip install PyPDF2
代码
import os
from PyPDF2 import PdfFileReader as pr
from PyPDF2 import PdfFileWriter as pw
def write_watermark(watermark_pdf_path: str, target_pdf_path: str):
result_pdf = pw()
pdf_file_name = os.path.basename(target_pdf_path)
f_target = open(target_pdf_path, 'rb')
f_watermark = open(watermark_pdf_path, 'rb')
target_pdf = pr(f_target)
watermark_page = pr(f_watermark).getPage(0)
for page in range(target_pdf.getNumPages()):
try: # 这一段try except是一个让我超级麻烦的bug，让我解决了一天。
target_pdf.getPage(page).mergePage(watermark_page)
result_pdf.addPage(target_pdf.getPage(page))
except Exception as e:
result_pdf.addPage(watermark_page)
if not os.path.exists("output"):
os.makedirs("output")
result_pdf.write(open("output/已添加水印_" + pdf_file_name, 'wb'))
f_target.close()
f_watermark.close()
def folder_pdf_files(folder: str) -> list[str]: # 一个文件夹里面有多少pdf文件
file_list = []
for a, b, c in os.walk(folder):
if b == []:
for filename in c:
if filename[-3:].lower() == 'pdf':
file_path = os.path.join(a, filename)
file_list.append(file_path)
print(folder, ": 有", len(file_list), "个pdf文件")
return file_list
def group_write_watermark(path_array: list[str], watermark_pdf_path: str): # 一组pdf文件添加水印
for pdf_path in path_array:
print(pdf_path, "添加水印中...")
write_watermark(watermark_pdf_path, pdf_path)
print("完成")
if __name__ == '__main__':
watermark_pdf_path = "水印文件.pdf"
folder_pdf = "目录" # 需要添加水印的pdf的目录
pdf_list = folder_pdf_files(folder_pdf)
group_write_watermark(pdf_list, watermark_pdf_path)
问题
UnicodeEncodeError: ‘latin-1’ codec can’t encode characters in position 8-9: ordinal not in range(256)
如果出现该错误，可以参考以下内容。
使用pypdf2出现编码问题
报错信息
‘latin-1’ codec can’t encode characters in position 8-11: ordinal not in range(256)
通常这情况是出现了中文字符编码问题
以下是使用pypdf2复制 pdf 时报错信息
//报错信息
<ipython-input-1-4f7e1b354328> in <module>()
14 output.addPage(p)
15 with open('D:\\Program Files\\2.pdf', 'wb') as f:
---> 16 output.write(f)
D:\Program Files (x86)\anaconda\lib\site-packages\PyPDF2\pdf.py in write(self, stream)
499 md5_hash = md5(key).digest()
500 key = md5_hash[:min(16, len(self._encrypt_key) + 5)]
--> 501 obj.writeToStream(stream, key)
502 stream.write(b_("\nendobj\n"))
503
D:\Program Files (x86)\anaconda\lib\site-packages\PyPDF2\generic.py in writeToStream(self, stream, encryption_key)
547 key.writeToStream(stream, encryption_key)
548 stream.write(b_(" "))
--> 549 value.writeToStream(stream, encryption_key)
550 stream.write(b_("\n"))
551 stream.write(b_(">>"))
D:\Program Files (x86)\anaconda\lib\site-packages\PyPDF2\generic.py in writeToStream(self, stream, encryption_key)
470
471 def writeToStream(self, stream, encryption_key):
--> 472 stream.write(b_(self))
473
474 def readFromStream(stream, pdf):
D:\Program Files (x86)\anaconda\lib\site-packages\PyPDF2\utils.py in b_(s)
236 return s
237 else:
--> 238 r = s.encode('latin-1')
239 if len(s) < 2:
240 bc[s] = r
UnicodeEncodeError: 'latin-1' codec can't encode characters in position 8-11: ordinal not in range(256)
解决方法
1、修改pypdf2包中的generic.py文件
由于我使用的是anaconda，路径为anaconda\Lib\site-packages\PyPDF2\generic.py
generic.py文件第488行原文
try:
return NameObject(name.decode('utf-8'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
# Name objects should represent irregular characters
# with a '#' followed by the symbol's hex number
if not pdf.strict:
warnings.warn("Illegal character in Name Object", utils.PdfReadWarning)
return NameObject(name)
else:
raise utils.PdfReadError("Illegal character in Name Object")
改成
try:
return NameObject(name.decode('utf-8'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
try:
return NameObject(name.decode('gbk'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
# Name objects should represent irregular characters
# with a '#' followed by the symbol's hex number
if not pdf.strict:
warnings.warn("Illegal character in Name Object", utils.PdfReadWarning)
return NameObject(name)
else:
raise utils.PdfReadError("Illegal character in Name Object")
2、修改pypdf2包中的utils.py文件
utils.py238行原文
r = s.encode('latin-1')
if len(s) < 2:
bc[s] = r
return r
修改为
try:
r = s.encode('latin-1')
if len(s) < 2:
bc[s] = r
return r
except Exception as e:
print(s)
r = s.encode('utf-8')
if len(s) < 2:
bc[s] = r
return r
问题解决
感悟
此代码的创新点在于可以实现文件夹遍历添加水印。
其实第一点也没有什么，我感觉我最有成功感的就是write_watermark函数里那段try except语句处，这个一段代码解决pdf空白页而发送的错误。解决了一天，网络上都没有解决方法。我摸着石头过河。
有一个问题就是，这个代码对于图片pdf的水印效果不好，因为图片pdf的也页面大小比普通的文字pdf大一些，难以控制水印的位置。我想的是在创建水印pdf的时候就把pdf的大小放大。
到此这篇关于Python实现为pdf添加水印功能的文章就介绍到这了,更多相关Python pdf水印内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
