今天,我尝试着实施解决方案,以便落实我的想法。
使用 ReportLab、pdfquery 和 PyPDF2,我正在尝试自动化在 PDF 文档的数百个页面上生成条形码的过程。
每个页面都需要有一个条形码。然而,如果页面右上角有一个字母(从 'A' 到 'E'),那么它需要使用与前一页相同的条形码。带有右上角字母的文件是具有类似信息的重复表格。
如果没有字母出现,则应在该页面上使用唯一的条形码号码(递增一即可)。
我的代码似乎可以工作,但我遇到了两个问题:
- 条形码会微微移动(小问题)。
- 条形码的值不会改变(重大问题)。所有页面上只设置了第一个条形码号码。
我似乎无法确定值为什么不会改变。有人有线索吗?
代码在这里:
import pdfquery
import os
from io import BytesIO
from PyPDF2 import PdfFileWriter, PdfFileReader
from reportlab.graphics.barcode import eanbc
from reportlab.graphics.shapes import Drawing
from reportlab.lib.pagesizes import letter
from reportlab.lib.units import mm
from reportlab.pdfgen import canvas
from reportlab.graphics import renderPDF
pdf = pdfquery.PDFQuery("letters-test.pdf")
total_pages = pdf.doc.catalog['Pages'].resolve()['Count']
print("Total pages", total_pages)
barcode_value = 12345670
output = PdfFileWriter()
for i in range(0, total_pages):
pdf.load(i) # Load page i into memory
duplicate_letter = pdf.pq('LTTextLineHorizontal:in_bbox("432,720,612,820")').text()
if duplicate_letter != '':
print("Page " + str(i+1) + " letter " + str(duplicate_letter))
print(barcode_value)
packet = BytesIO()
c = canvas.Canvas(packet, pagesize=letter)
# draw the eanbc8 code
barcode_eanbc8 = eanbc.Ean8BarcodeWidget(str(barcode_value))
bounds = barcode_eanbc8.getBounds()
width = bounds[2] - bounds[0]
height = bounds[3] - bounds[1]
d = Drawing(50, 10)
d.add(barcode_eanbc8)
renderPDF.draw(d, c, 400, 700)
c.save()
packet.seek(0)
new_pdf = PdfFileReader(packet)
# read existing PDF
existing_pdf = PdfFileReader(open("letters-test.pdf", "rb"))
# add the "watermark" (which is the new pdf) on the existing page
page = existing_pdf.getPage(i)
page.mergePage(new_pdf.getPage(0))
output.addPage(page)
else:
# increment barcode value
barcode_value += 1
print("Page " + str(i+1) + " isn't a duplicate.")
print(barcode_value)
packet = BytesIO()
c = canvas.Canvas(packet, pagesize=letter)
# draw the eanbc8 code
barcode_eanbc8 = eanbc.Ean8BarcodeWidget(str(barcode_value))
bounds = barcode_eanbc8.getBounds()
width = bounds[2] - bounds[0]
height = bounds[3] - bounds[1]
d = Drawing(50, 10)
d.add(barcode_eanbc8)
renderPDF.draw(d, c, 420, 710)
c.save()
packet.seek(0)
new_pdf = PdfFileReader(packet)
# read existing PDF
existing_pdf = PdfFileReader(open("letters-test.pdf", "rb"))
# add the "watermark" (which is the new pdf) on the existing page
page = existing_pdf.getPage(i)
page.mergePage(new_pdf.getPage(0))
output.addPage(page)
# Clear page i from memory and re load.
# pdf = pdfquery.PDFQuery("letters-test.pdf")
outputStream = open("newpdf.pdf", "wb")
output.write(outputStream)
outputStream.close()