SignFilter.py 文件源码

def _generate_form(self):
        font_xref = self._get_font_reference()
        seal_template = PDFTemplate(pkgutil.get_data("llpdf.resources", "seal.pdft"))
        seal_xref = seal_template.merge_into_pdf(self._pdf)["SealObject"]

        sign_template = PDFTemplate(pkgutil.get_data("llpdf.resources", "sign_form.pdft"))
        sign_template["FontXRef"] = font_xref
        sign_template["SealFormXRef"] = seal_xref
        signform_xref = sign_template.merge_into_pdf(self._pdf)["SignFormObject"]

        signform = self._pdf.lookup(signform_xref)
        signform.content[PDFName("/BBox")] = self._get_signature_bbox()
        signform_data = signform.stream.decode()

        (posx, posy, width, height) = self._get_signature_bbox()
        signform_vars = {
            "WIDTH":        b"%.0f" % (width - 1),
            "HEIGHT":       b"%.0f" % (height - 1),
            "TEXT":         self._get_signing_text(),
        }
        for (varname, replacement) in signform_vars.items():
            key = ("${" + varname + "}").encode("ascii")
            signform_data = signform_data.replace(key, replacement)
        signform.set_stream(EncodedObject.create(signform_data, compress = True))
        return signform_xref