如何将JSignature签名绘制到ReportLab生成的PDF画布中？

我正在尝试将签名写入PDF文件，使用的工具是JSignature和ReportLab。目前我的代码已成功将数据写入文件和数据库，但始终无法实现将签名绘制到PDF画布中。请问有人成功实现过将签名传入画布的操作吗？

相关代码 #

pdf.py #

import io
from django.core.files.base import ContentFile
from reportlab.lib.units import inch
from reportlab.pdfgen import canvas
from reportlab.lib.utils import ImageReader


def create_pdf(parent):
    # create a file-like buffer to receive PDF data
    buffer = io.BytesIO()

    # create the pdf object, using the buffer as its "file"
    p = canvas.Canvas(buffer)
    # create text
    textobject = p.beginText()
    # start text at top left of page
    textobject.setTextOrigin(inch, 11*inch)
    # set font and size
    textobject.setFont("Helvetica-Bold", 18)
    textobject.textLine("My Document")
    textobject.textLine("")

    # write page 1
    textobject.setFont("Helvetica", 12)

    p_name = f'Name: {participant.first_name} {participant.middle_initial} {participant.last_name}'
    textobject.textLine(p_name)

    sig = f'Signature:'
    textobject.textLine(sig)

----insert signature here----


    # write created text to canvas
    p.drawText(textobject)
    # close the pdf canvas
    p.showPage()
    p.save()

    buffer.seek(0)
    # get content of buffer
    pdf_data = buffer.getvalue()
    # save to django File object
    file_data = ContentFile(pdf_data)
    # name the file
    file_data.name = f'{participant.last_name}.pdf'
    # 
    participant.pdf = file_data
    participant.save()

Model #

class Participant(models.Model):

    first_name = models.CharField(max_length=50)
    middle_initial = models.CharField(max_length=50, blank=True)
    last_name = models.CharField(max_length=50, blank=True)
    signature = JSignatureField()
    pdf = models.FileField(blank=True, null=True)

内容的提问来源于stack exchange，提问作者cbirch