Python|reportlab实现pdf内容填充

近期因工作需要要进行某个承诺书的签署文件生成，需要在固定的PDF模板上填充上部门、姓名、日期信息。之前使用过福昕PDF编辑器，体验较为不错，但这次要生成的PDF数量有300份，手工逐个处理自然是不便的。在《Python|PyPDF2实现PDF自动拆分》中曾写过利用 PyPDF2 实现PDF文件的拆分，这次我们用python的reportlab库尝试下PDF的生成。

PDF is the global standard for electronic documents. It supports high-quality printing yet is totally portable across platforms, thanks to the freely available Acrobat Reader. Any application which previously generated hard copy reports or driving a printer can benefit from making PDF documents instead; these can be archived, emailed, placed on the web, or printed out the old-fashioned way. However, the PDF file format is a complex indexed binary format which is impossible to type directly. The PDF format specification is more than 600 pages long and PDF files must provide precise byte offsets – a single extra character placed anywhere in a valid PDF document can render it invalid. This makes it harder to generate than HTML.

PDF文件格式是一种复杂的索引二进制格式，不可能直接输入。 reportlab 的处理逻辑是生成一个画布，通过笛卡尔坐标系在位图上创建具有矢量格式的文件内容，之后根据加工后的页码创建一个PDF。

思路

准备好待签署的人员清单及PDF模板，分析PDF模板（待签署页码，签署区域），生成签署内容并合成签署页，合成完成PDF并输出。

源码如下

from PyPDF2 import PdfWriter, PdfReader
import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.pdfbase import pdfmetrics

pdfmetrics.registerFont(TTFont('仿宋', r'C:\Windows\Fonts\simfang.ttf'))

def PdfProcess(pdfInPath,pdfInName,alterPageNumber,dept,username,yearv,monthv,daysv):
    # 创建PDF流
    packet = io.BytesIO()
    can = canvas.Canvas(packet, pagesize=letter)
    can.setFillColorRGB(0, 0, 0)  # 字体黑色
    can.setFont("仿宋", 16)  # 字体样式
    can.drawString(328, 307, dept)  # 填充部门
    can.drawString(343, 249, username)  # 姓名
    can.drawString(325, 192, yearv)  # 年
    can.drawString(380, 192, monthv)  # 月
    can.drawString(420, 192, daysv)  # 日
    can.save()
 
    # 合成PDF页面
    packet.seek(0)
    new_pdf = PdfReader(packet)
    existing_pdf = PdfReader(open(r'{}\{}'.format(pdfInPath,pdfInName), 'rb'))
    output = PdfWriter()
    page = existing_pdf.pages[alterPageNumber-1]
    page.merge_page(new_pdf.pages[0])

    # 合成最终PDF
    existing_numPages = len(existing_pdf.pages)
    for i in range(0,existing_numPages):
        if i == alterPageNumber-1:
            output.add_page(page)
        else:
            output.add_page(existing_pdf.pages[i])
    
    # 输出最终pdf
    outputStream = open(r'C:\Users\admin\Desktop\签署文件生成\{}-{}.pdf'.format(dept,username), "wb")
    output.write(outputStream)
    outputStream.close()

if __name__ == '__main__':
    pdfInPath = r'C:\Users\admin\Desktop\签署文件生成'
    pdfInName = '模板.pdf'
    alterPageNumber = 5
    s = open(r'C:\Users\admin\Desktop\签署文件生成\签署清单.txt',encoding='utf-8')
    for line in s:
        line = line.split()
        dept = line[0]
        username = line[1]
        yearv = line[2]
        monthv = line[3]
        daysv = line[4]
        PdfProcess(pdfInPath,pdfInName,alterPageNumber,dept,username,yearv,monthv,daysv)
        print('已完成{}-{}.pdf的生成'.format(dept,username))