如何在python中使用pyPDF2更改pdf文件中的字体

如何在pyPDF 2模块中更改字体

我尝试了打印（帮助（canvas.canvas））

我尝试了

initialFontName=None

和

initialFontSize=None

但是我的文字没有改变。另外，我使用raspberry pi和raspbian操作系统来实现这一点

这是我的密码

        can = canvas.Canvas(packet, pagesize=letter, initialFontName = 'Helvetica', initialFontSize = 5)
        now = datetime.datetime.now()

        can.drawString(250, 500, self.get_Firstn1 + ' ' + self.get_Middlen1 +' ' + self.get_Lastn1)
        can.drawString(300, 550, "Hello World")
        can.drawString(350, 600,"Hello")

        can.save()

        packet.seek(0)
        new_pdf = PdfFileReader(packet)


        existing_pdf = PdfFileReader(open("Sample.pdf", "rb"))
        existing_pdf.decrypt('')
        output = PdfFileWriter()
            # add the "watermark" (which is the new pdf) on the existing page

        page = existing_pdf.getPage(0)
        page.mergePage(new_pdf.getPage(0))

        output.addPage(page)

        #write "output" to a real file
        outputStream = open("destination.pdf", "wb")
        output.write(outputStream)
        outputStream.close()
            #open pdf file
        opener ="open" if sys.platform == "darwin"else "xdg-open"
        subprocess.call([opener, "destination.pdf"])

我试着改变诸如Arial、Times New Roman、Cambria等字体，但它只接受Helvetica，文本大小和字体没有改变