[ADD] stamp_sign: add company stamp field

This commit introduces the stamp_sign module, which adds a new Stamp
field type to the core Sign application.

before:
The Sign application only supported standard text signatures and initials.
There was no built-in way to apply a company-style stamp with structured
information like an address and logo.

after:
A new Stamp type is available in the Sign editor. Users can drag a
stamp field onto the document. During the signing process, clicking the
field opens a dialog to input company details (name, address, VAT, logo).
This information is rendered into a stamp image and applied to the
document. The final signed PDF includes stamp.

impact:
This extends the sign module with a new stamp type, improving its
utility for official business documents that require a formal company stamp.

Author: arkp-odoo

stamp_sign/__init__.py

@@ -0,0 +1,3 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+from . import models
+from . import controllers

stamp_sign/__manifest__.py

@@ -0,0 +1,23 @@
+{
+    "name": "Stamp Sign",
+    "version": "1.0",
+    "depends": ["sign"],
+    "category": "Sign",
+    "data": [
+        "data/sign_data.xml",
+        "views/sign_request_templates.xml",
+    ],
+    "assets": {
+        "web.assets_backend": [
+            "stamp_sign/static/src/components/sign_request/*",
+            "stamp_sign/static/src/dialogs/*",
+        ],
+        "sign.assets_public_sign": [
+            "stamp_sign/static/src/components/sign_request/*",
+            "stamp_sign/static/src/dialogs/*",
+        ],
+    },
+    "installable": True,
+    "application": True,
+    "license": "LGPL-3",
+}

stamp_sign/controllers/__init__.py

@@ -0,0 +1,2 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+from . import main

stamp_sign/controllers/main.py

@@ -0,0 +1,71 @@
+from odoo import http
+from odoo.addons.sign.controllers.main import Sign # type: ignore
+
+
+class Sign(Sign):
+    def get_document_qweb_context(self, sign_request_id, token, **post):
+        data = super().get_document_qweb_context(sign_request_id, token, **post)
+        current_request_item = data["current_request_item"]
+        sign_item_types = data["sign_item_types"]
+        company_logo = http.request.env.user.company_id.logo
+        if company_logo:
+            data["logo"] = "data:image/png;base64,%s" % company_logo.decode()
+        else:
+            data["logo"] = False
+
+        if current_request_item:
+            user_stamp = current_request_item._get_user_signature_asset("stamp_sign_stamp")
+            user_stamp_frame = current_request_item._get_user_signature_asset("stamp_sign_stamp_frame")
+
+            encoded_user_stamp = (
+                "data:image/png;base64,%s" % user_stamp.decode()
+                if user_stamp
+                else False
+            )
+            encoded_user_stamp_frame = (
+                "data:image/png;base64,%s" % user_stamp_frame.decode()
+                if user_stamp_frame
+                else False
+            )
+            stamp_item_type = next(
+                (
+                    item_type
+                    for item_type in sign_item_types
+                    if item_type["item_type"] == "stamp"
+                ),
+                None,
+            )
+            if stamp_item_type:
+                stamp_item_type["auto_value"] = encoded_user_stamp
+                stamp_item_type["frame_value"] = encoded_user_stamp_frame
+
+        return data
+
+    @http.route(["/sign/update_user_signature"], type="json", auth="user")
+    def update_signature(
+        self, sign_request_id, role, signature_type=None, datas=None, frame_datas=None
+    ):
+        user = http.request.env.user
+        if not user or signature_type not in [
+            "sign_signature",
+            "sign_initials",
+            "stamp_sign_stamp",
+        ]:
+            return False
+
+        sign_request_item_sudo = (
+            http.request.env["sign.request.item"]
+            .sudo()
+            .search(
+                [("sign_request_id", "=", sign_request_id), ("role_id", "=", role)],
+                limit=1,
+            )
+        )
+
+        allowed = sign_request_item_sudo.partner_id.id == user.partner_id.id
+        if not allowed:
+            return False
+        user[signature_type] = datas[datas.find(",") + 1 :]
+        if frame_datas:
+            user[signature_type + "_frame"] = frame_datas[frame_datas.find(",") + 1 :]
+        return True

stamp_sign/data/sign_data.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<odoo>
+    <record model="sign.item.type" id="stamp_item_type">
+        <field name="name">Stamp</field>
+        <field name="item_type">stamp</field>
+        <field name="tip">stamp</field>
+        <field name="placeholder">Stamp</field>
+        <field name="default_width" type="float">0.300</field>
+        <field name="default_height" type="float">0.10</field>
+        <field name="icon">fa-legal</field>
+    </record>
+</odoo>

stamp_sign/models/__init__.py

@@ -0,0 +1,4 @@
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+from . import sign_template
+from . import res_users
+from . import sign_request

stamp_sign/models/res_users.py

@@ -0,0 +1,22 @@
+from odoo import models, fields
+
+SIGN_USER_FIELDS = ["stamp_sign_stamp","stamp_sign_stamp_frame"]
+
+
+class ResUsers(models.Model):
+    _inherit = "res.users"
+
+    @property
+    def SELF_READABLE_FIELDS(self):
+        return super().SELF_READABLE_FIELDS + SIGN_USER_FIELDS
+
+    @property
+    def SELF_WRITEABLE_FIELDS(self):
+        return super().SELF_WRITEABLE_FIELDS + SIGN_USER_FIELDS
+
+    stamp_sign_stamp = fields.Binary(
+        string="Company Stamp", copy=False, groups="base.group_user"
+    )
+    stamp_sign_stamp_frame = fields.Binary(
+        string="Company Stamp Frame", copy=False, groups="base.group_user"
+    )

stamp_sign/models/sign_request.py

@@ -0,0 +1,249 @@
+import base64
+import io
+import time
+
+from PIL import UnidentifiedImageError
+from reportlab.lib.utils import ImageReader
+from reportlab.pdfgen import canvas
+
+from odoo import _, models, Command
+from odoo.tools import format_date
+from odoo.exceptions import UserError, ValidationError
+from odoo.tools.pdf import PdfFileReader, PdfFileWriter
+
+try:
+    from PyPDF2.errors import PdfReadError # type: ignore
+except ImportError:
+    from PyPDF2.utils import PdfReadError
+
+
+def _fix_image_transparency(image):
+    pixels = image.load()
+    for x in range(image.size[0]):
+        for y in range(image.size[1]):
+            if pixels[x, y] == (0, 0, 0, 0):
+                pixels[x, y] = (255, 255, 255, 0)
+
+
+class SignRequest(models.Model):
+    _inherit = "sign.request"
+
+    def _generate_completed_document(self, password=""):
+        self.ensure_one()
+        self._validate_document_state()
+
+        if not self.template_id.sign_item_ids:
+            self._copy_template_to_completed_document()
+        else:
+            old_pdf = self._load_template_pdf(password)
+            new_pdf_data = self._create_signed_overlay(old_pdf)
+            self._merge_pdfs_and_store(old_pdf, new_pdf_data, password)
+
+        attachment = self._create_attachment_from_completed_doc()
+        log_attachment = self._create_completion_certificate()
+        self._attach_completed_documents(attachment, log_attachment)
+
+    def _validate_document_state(self):
+        if self.state != "signed":
+            raise UserError(
+                _(
+                    "The completed document cannot be created because the sign request is not fully signed"
+                )
+            )
+
+    def _copy_template_to_completed_document(self):
+        self.completed_document = self.template_id.attachment_id.datas
+
+    def _load_template_pdf(self, password):
+        try:
+            pdf_reader = PdfFileReader(
+                io.BytesIO(base64.b64decode(self.template_id.attachment_id.datas)),
+                strict=False,
+                overwriteWarnings=False,
+            )
+            pdf_reader.getNumPages()
+        except PdfReadError:
+            raise ValidationError(_("ERROR: Invalid PDF file!"))
+
+        if pdf_reader.isEncrypted and not pdf_reader.decrypt(password):
+            return
+
+        return pdf_reader
+
+    def _create_signed_overlay(self, old_pdf):
+        font = self._get_font()
+        normalFontSize = self._get_normal_font_size()
+        packet = io.BytesIO()
+        can = canvas.Canvas(packet, pagesize=self.get_page_size(old_pdf))
+        items_by_page, values = self._collect_items_and_values()
+
+        for p in range(0, old_pdf.getNumPages()):
+            page = old_pdf.getPage(p)
+            width, height = self._get_page_dimensions(page)
+            self._apply_page_rotation(can, page, width, height)
+
+            for item in items_by_page.get(p + 1, []):
+                self._draw_item(
+                    can, item, values.get(item.id), width, height, font, normalFontSize
+                )
+            can.showPage()
+
+        can.save()
+        return PdfFileReader(packet, overwriteWarnings=False)
+
+    def _collect_items_and_values(self):
+        items_by_page = self.template_id._get_sign_items_by_page()
+        item_ids = [id for items in items_by_page.values() for id in items.ids]
+        values_dict = self.env["sign.request.item.value"]._read_group(
+            [("sign_item_id", "in", item_ids), ("sign_request_id", "=", self.id)],
+            groupby=["sign_item_id"],
+            aggregates=[
+                "value:array_agg",
+                "frame_value:array_agg",
+                "frame_has_hash:array_agg",
+            ],
+        )
+        values = {
+            item: {"value": vals[0], "frame": frames[0], "frame_has_hash": hashes[0]}
+            for item, vals, frames, hashes in values_dict
+        }
+        return items_by_page, values
+
+    def _get_page_dimensions(self, page):
+        width = float(abs(page.mediaBox.getWidth()))
+        height = float(abs(page.mediaBox.getHeight()))
+        return width, height
+
+    def _apply_page_rotation(self, can, page, width, height):
+        rotation = page.get("/Rotate", 0)
+        if isinstance(rotation, int):
+            can.rotate(rotation)
+            if rotation == 90:
+                width, height = height, width
+                can.translate(0, -height)
+            elif rotation == 180:
+                can.translate(-width, -height)
+            elif rotation == 270:
+                width, height = height, width
+                can.translate(-width, 0)
+
+    def _draw_item(self, can, item, value_dict, width, height, font, normalFontSize):
+        if not value_dict:
+            return
+
+        value, frame = value_dict["value"], value_dict["frame"]
+        if frame:
+            self._draw_image(can, frame, item, width, height)
+
+        draw_method = getattr(self, f"_draw_{item.type_id.item_type}", None)
+        if draw_method:
+            draw_method(can, item, value, width, height, font, normalFontSize)
+
+    def _draw_image(self, can, frame_data, item, width, height):
+        try:
+            image_reader = ImageReader(
+                io.BytesIO(base64.b64decode(frame_data.split(",")[1]))
+            )
+        except UnidentifiedImageError:
+            raise ValidationError(
+                _(
+                    "There was an issue downloading your document. Please contact an administrator."
+                )
+            )
+
+        _fix_image_transparency(image_reader._image)
+        can.drawImage(
+            image_reader,
+            width * item.posX,
+            height * (1 - item.posY - item.height),
+            width * item.width,
+            height * item.height,
+            "auto",
+            True,
+        )
+
+    def _draw_signature(self, can, item, value, width, height, *_):
+        self._draw_image(can, value, item, width, height)
+
+    _draw_initial = _draw_signature
+    _draw_stamp = _draw_signature
+
+    def _merge_pdfs_and_store(self, old_pdf, overlay_pdf, password):
+        new_pdf = PdfFileWriter()
+        for i in range(old_pdf.getNumPages()):
+            page = old_pdf.getPage(i)
+            page.mergePage(overlay_pdf.getPage(i))
+            new_pdf.addPage(page)
+        if old_pdf.isEncrypted:
+            new_pdf.encrypt(password)
+
+        output = io.BytesIO()
+        try:
+            new_pdf.write(output)
+        except PdfReadError:
+            raise ValidationError(
+                _(
+                    "There was an issue downloading your document. Please contact an administrator."
+                )
+            )
+        self.completed_document = base64.b64encode(output.getvalue())
+        output.close()
+
+    def _create_attachment_from_completed_doc(self):
+        filename = (
+            self.reference
+            if self.reference.endswith(".pdf")
+            else f"{self.reference}.pdf"
+        )
+        return self.env["ir.attachment"].create(
+            {
+                "name": filename,
+                "datas": self.completed_document,
+                "type": "binary",
+                "res_model": self._name,
+                "res_id": self.id,
+            }
+        )
+
+    def _create_completion_certificate(self):
+        public_user = (
+            self.env.ref("base.public_user", raise_if_not_found=False) or self.env.user
+        )
+        pdf_content, _ = (
+            self.env["ir.actions.report"]
+            .with_user(public_user)
+            .sudo()
+            ._render_qweb_pdf(
+                "sign.action_sign_request_print_logs",
+                self.ids,
+                data={
+                    "format_date": format_date,
+                    "company_id": self.communication_company_id,
+                },
+            )
+        )
+        return self.env["ir.attachment"].create(
+            {
+                "name": f"Certificate of completion - {time.strftime('%Y-%m-%d - %H:%M:%S')}.pdf",
+                "raw": pdf_content,
+                "type": "binary",
+                "res_model": self._name,
+                "res_id": self.id,
+            }
+        )
+
+    def _attach_completed_documents(self, doc_attachment, log_attachment):
+        self.completed_document_attachment_ids = [
+            Command.set([doc_attachment.id, log_attachment.id])
+        ]
+
+
+class SignRequestItem(models.Model):
+    _inherit = "sign.request.item"
+
+    def _get_user_signature_asset(self, asset_type):
+        self.ensure_one()
+        sign_user = self.partner_id.user_ids[:1]
+        if sign_user and asset_type in ["stamp_sign_stamp", "stamp_sign_stamp_frame"]:
+            return sign_user[asset_type]
+        return False