Python、JSignature 和 ReportLab答案

【问题标题】：Python, JSignature, and ReportLabPython、JSignature 和 ReportLab
【发布时间】：2022-08-04 12:43:38
【问题描述】：

我正在寻找为 PDF 写签名。我正在使用 JSignature 和 Reportlab。我的代码成功地将数据写入文件和数据库。我只是不知道如何将签名写入画布。有没有人成功地将签名传递到画布中？

先感谢您。

这是我的代码：

pdf文件


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()

模型：


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)

标签： python django pdf reportlab jsignature

【解决方案1】：

对于那些对我如何能够实现此功能感兴趣的人。主要问题是将图像拉入 PDF 时将完全变黑。这是必需的：

在您看来：

使用Jsignature draw_signature 函数获取图像：

rsr_image = draw_signature(signature)

将签名保存为PNG，然后存储


            # save signature as png to prevent darkening, save to model
            rsr_file_name = str(new_parent.id)+'_rsr.png'
            buffer = BytesIO()
            rsr_image.save(buffer, 'PNG')
            new_parent.rsr_image.save(rsr_file_name, File(buffer))

创建以下函数，以便...

打开图像，为图像创建新背景，然后保存。


def get_jpeg_image(new_parent):
    # open png image
    png_image = Image.open(new_parent.rsr_image)
    # create new image with 'RGB' mode which is compatible with jpeg,
    # with same size as old and with white(255,255,255) background
    bg = Image.new("RGB", png_image.size, (255, 255, 255))
    # paste old image pixels in new background
    bg.paste(png_image, png_image)
    # give image file name
    file_name_jpeg = str(new_parent.id)+'.jpg'
    bg.save(file_name_jpeg)
    return file_name_jpeg

在创建 PDF 函数中引用该函数以将 PNG 转换为 JPG


jpeg_image = get_jpeg_image(participant)

希望这可以帮助某人。

【讨论】：