PDF 签名

复制from PyPDF2 import PdfReader, PdfWriter
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas
import io

# 1. 创建签名图片的 PDF 覆盖层（透明背景）
signature_path = "signature.png"  # 签名图片文件
output_pdf = "signed_document.pdf"
input_pdf = "original.pdf"

# 生成签名覆盖页（A4 大小，签名放在右下角）
packet = io.BytesIO()
c = canvas.Canvas(packet, pagesize=letter)
c.drawImage(signature_path, 400, 50, width=150, height=60, mask='auto')
c.save()
packet.seek(0)
overlay = PdfReader(packet)

# 2. 合并到原 PDF 每一页
reader = PdfReader(input_pdf)
writer = PdfWriter()
for page in reader.pages:
    page.merge_page(overlay.pages[0])
    writer.add_page(page)

with open(output_pdf, "wb") as f:
    writer.write(f)
print(f"签名完成：{output_pdf}")

复制package main

import (
	"github.com/pdfcpu/pdfcpu/pkg/api"
	"github.com/pdfcpu/pdfcpu/pkg/pdfcpu"
	"github.com/pdfcpu/pdfcpu/pkg/types"
	"image"
	_ "image/png"
	"os"
)

func main() {
	// 读取签名图片
	imgFile, _ := os.Open("signature.png")
	defer imgFile.Close()
	img, _, _ := image.Decode(imgFile)

	// 配置签名位置（右下角，单位：点）
	pos := types.Rectangle{LLx: 400, LLy: 50, URx: 550, URy: 110}
	watermark := pdfcpu.Watermark{
		Image:   img,
		Pos:     pos,
		Opacity: 1.0,
		OnTop:   true,
	}

	// 应用到 PDF 所有页面
	if err := api.AddWatermarksFile("original.pdf", "", "signed.pdf", watermark, nil, nil); err != nil {
		panic(err)
	}
	println("签名完成：signed.pdf")
}

复制const { PDFDocument } = require('pdf-lib');
const fs = require('fs');

async function signPDF() {
  // 读取原 PDF 和签名图片
  const pdfBytes = fs.readFileSync('original.pdf');
  const signatureBytes = fs.readFileSync('signature.png');
  
  const pdfDoc = await PDFDocument.load(pdfBytes);
  const signatureImage = await pdfDoc.embedPng(signatureBytes);
  
  // 获取所有页面并添加签名
  const pages = pdfDoc.getPages();
  for (const page of pages) {
    page.drawImage(signatureImage, {
      x: 400,
      y: 50,
      width: 150,
      height: 60,
      opacity: 0.9,
    });
  }
  
  // 保存
  const signedBytes = await pdfDoc.save();
  fs.writeFileSync('signed.pdf', signedBytes);
  console.log('签名完成：signed.pdf');
}

signPDF().catch(console.error);