report_qweb_pdf_watermark (#86)

report_qweb_pdf_watermark/models/report.py

@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+# © 2016 Therp BV <http://therp.nl>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+from base64 import b64decode
+from logging import getLogger
+from pyPdf import PdfFileWriter, PdfFileReader
+from pyPdf.utils import PdfReadError
+from PIL import Image
+from StringIO import StringIO
+from openerp import api, models, tools
+logger = getLogger(__name__)
+
+
+class Report(models.Model):
+    _inherit = 'report'
+
+    @api.v7
+    def get_pdf(
+        self, cr, uid, ids, report_name, html=None, data=None, context=None
+    ):
+        # pylint: disable=R8110
+        # this override cannot be done in v8 api
+        result = super(Report, self).get_pdf(
+            cr, uid, ids, report_name, html=html, data=data,
+            context=context
+        )
+        report = self._get_report_from_name(cr, uid, report_name)
+        watermark = None
+        if report.pdf_watermark:
+            watermark = b64decode(report.pdf_watermark)
+        else:
+            env = api.Environment(cr, uid, context)
+            watermark = tools.safe_eval(
+                report.pdf_watermark_expression or 'None',
+                dict(env=env, docs=env[report.model].browse(ids)),
+            )
+            if watermark:
+                watermark = b64decode(watermark)
+
+        if not watermark:
+            return result
+
+        pdf = PdfFileWriter()
+        pdf_watermark = None
+        try:
+            pdf_watermark = PdfFileReader(StringIO(watermark))
+        except PdfReadError:
+            # let's see if we can convert this with pillow
+            try:
+                image = Image.open(StringIO(watermark))
+                pdf_buffer = StringIO()
+                if image.mode != 'RGB':
+                    image = image.convert('RGB')
+                resolution = image.info.get(
+                    'dpi', report.paperformat_id.dpi or 90
+                )
+                if isinstance(resolution, tuple):
+                    resolution = resolution[0]
+                image.save(pdf_buffer, 'pdf', resolution=resolution)
+                pdf_watermark = PdfFileReader(pdf_buffer)
+            except:
+                logger.exception('Failed to load watermark')
+
+        if not pdf_watermark:
+            logger.error(
+                'No usable watermark found, got %s...', watermark[:100]
+            )
+            return result
+
+        if pdf_watermark.numPages < 1:
+            logger.error('Your watermark pdf does not contain any pages')
+            return result
+        if pdf_watermark.numPages > 1:
+            logger.debug('Your watermark pdf contains more than one page, '
+                         'all but the first one will be ignored')
+
+        for page in PdfFileReader(StringIO(result)).pages:
+            watermark_page = pdf.addBlankPage(
+                page.mediaBox.getWidth(), page.mediaBox.getHeight()
+            )
+            watermark_page.mergePage(pdf_watermark.getPage(0))
+            watermark_page.mergePage(page)
+
+        pdf_content = StringIO()
+        pdf.write(pdf_content)
+
+        return pdf_content.getvalue()