Add unit-tests to avoid regression in Server printing to PDF output format

In QGIS 3.4, Selection can be printed in Image output and not in PDF or SVG output.

A fix has been done 2752f83 to fix inconsistent use of layout render context flags, and draw selection is activated with a flag.

Author: rldhont

tests/src/python/test_qgsserver_wms_getprint.py

@@ -28,12 +28,18 @@
 
 from qgis.testing import unittest
 from qgis.PyQt.QtCore import QSize
+from qgis.PyQt.QtGui import QImage, QPainter
+from qgis.PyQt.QtSvg import QSvgRenderer, QSvgGenerator
 
 import osgeo.gdal  # NOQA
+import tempfile
+import base64
+import subprocess
 
 from test_qgsserver import QgsServerTestBase
-from qgis.core import QgsProject
+from qgis.core import QgsProject, QgsRenderChecker
 from qgis.server import QgsServerRequest
+from utilities import getExecutablePath, unitTestDataPath
 
 # Strip path and content length because path may vary
 RE_STRIP_UNCHECKABLE = b'MAP=[^"]+|Content-Length: \d+'
@@ -42,6 +48,132 @@
 
 class TestQgsServerWMSGetPrint(QgsServerTestBase):
 
+    def _pdf_to_png(self, pdf_file_path, rendered_file_path, page, dpi=96):
+
+        # PDF-to-image utility
+        # look for Poppler w/ Cairo, then muPDF
+        # * Poppler w/ Cairo renders correctly
+        # * Poppler w/o Cairo does not always correctly render vectors in PDF to image
+        # * muPDF renders correctly, but slightly shifts colors
+        for util in [
+            'pdftocairo',
+            # 'mudraw',
+        ]:
+            PDFUTIL = getExecutablePath(util)
+            if PDFUTIL:
+                break
+
+        # noinspection PyUnboundLocalVariable
+        if not PDFUTIL:
+            assert False, ('PDF-to-image utility not found on PATH: '
+                           'install Poppler (with Cairo)')
+
+        if PDFUTIL.strip().endswith('pdftocairo'):
+            filebase = os.path.join(
+                os.path.dirname(rendered_file_path),
+                os.path.splitext(os.path.basename(rendered_file_path))[0]
+            )
+            call = [
+                PDFUTIL, '-png', '-singlefile', '-r', str(dpi),
+                '-x', '0', '-y', '0', '-f', str(page), '-l', str(page),
+                pdf_file_path, filebase
+            ]
+        elif PDFUTIL.strip().endswith('mudraw'):
+            call = [
+                PDFUTIL, '-c', 'rgba',
+                '-r', str(dpi), '-f', str(page), '-l', str(page),
+                # '-b', '8',
+                '-o', rendered_file_path, pdf_file_path
+            ]
+        else:
+            return False, ''
+
+        print("exportToPdf call: {0}".format(' '.join(call)))
+        try:
+            subprocess.check_call(call)
+        except subprocess.CalledProcessError as e:
+            assert False, ("exportToPdf failed!\n"
+                           "cmd: {0}\n"
+                           "returncode: {1}\n"
+                           "message: {2}".format(e.cmd, e.returncode, e.message))
+
+    def _pdf_diff(self, pdf, control_image, max_diff, max_size_diff=QSize(), dpi=96):
+
+        temp_pdf = os.path.join(tempfile.gettempdir(), "%s_result.pdf" % control_image)
+
+        with open(temp_pdf, "wb") as f:
+            f.write(pdf)
+
+        temp_image = os.path.join(tempfile.gettempdir(), "%s_result.png" % control_image)
+        self._pdf_to_png(temp_pdf, temp_image, dpi=dpi, page=1)
+
+        control = QgsRenderChecker()
+        control.setControlPathPrefix("qgis_server")
+        control.setControlName(control_image)
+        control.setRenderedImage(temp_image)
+        if max_size_diff.isValid():
+            control.setSizeTolerance(max_size_diff.width(), max_size_diff.height())
+        return control.compareImages(control_image, max_diff), control.report()
+
+    def _pdf_diff_error(self, response, headers, image, max_diff=100, max_size_diff=QSize(), unittest_data_path='control_images', dpi=96):
+
+        reference_path = unitTestDataPath(unittest_data_path) + '/qgis_server/' + image + '/' + image + '.pdf'
+        self.store_reference(reference_path, response)
+
+        self.assertEqual(
+            headers.get("Content-Type"), 'application/pdf',
+            "Content type is wrong: %s instead of %s\n%s" % (headers.get("Content-Type"), 'application/pdf', response))
+
+        test, report = self._pdf_diff(response, image, max_diff, max_size_diff, dpi)
+
+        with open(os.path.join(tempfile.gettempdir(), image + "_result.pdf"), "rb") as rendered_file:
+            if not os.environ.get('ENCODED_OUTPUT'):
+                message = "PDF is wrong\: rendered file %s/%s_result.%s" % (tempfile.gettempdir(), image, 'pdf')
+            else:
+                encoded_rendered_file = base64.b64encode(rendered_file.read())
+                message = "PDF is wrong\n%s\File:\necho '%s' | base64 -d >%s/%s_result.%s" % (
+                    report, encoded_rendered_file.strip().decode('utf8'), tempfile.gettempdir(), image, 'pdf'
+                )
+
+        with open(os.path.join(tempfile.gettempdir(), image + "_result.png"), "rb") as rendered_file:
+            if not os.environ.get('ENCODED_OUTPUT'):
+                message = "Image is wrong\: rendered file %s/%s_result.%s" % (tempfile.gettempdir(), image, 'png')
+            else:
+                encoded_rendered_file = base64.b64encode(rendered_file.read())
+                message = "Image is wrong\n%s\nImage:\necho '%s' | base64 -d >%s/%s_result.%s" % (
+                    report, encoded_rendered_file.strip().decode('utf8'), tempfile.gettempdir(), image, 'png'
+                )
+
+        # If the failure is in image sizes the diff file will not exists.
+        if os.path.exists(os.path.join(tempfile.gettempdir(), image + "_result_diff.png")):
+            with open(os.path.join(tempfile.gettempdir(), image + "_result_diff.png"), "rb") as diff_file:
+                if not os.environ.get('ENCODED_OUTPUT'):
+                    message = "Image is wrong\: diff file %s/%s_result_diff.%s" % (tempfile.gettempdir(), image, 'png')
+                else:
+                    encoded_diff_file = base64.b64encode(diff_file.read())
+                    message += "\nDiff:\necho '%s' | base64 -d > %s/%s_result_diff.%s" % (
+                        encoded_diff_file.strip().decode('utf8'), tempfile.gettempdir(), image, 'png'
+                    )
+
+        self.assertTrue(test, message)
+
+    def _svg_to_png(svg_file_path, rendered_file_path, width):
+        svgr = QSvgRenderer(svg_file_path)
+
+        height = width / svgr.viewBoxF().width() * svgr.viewBoxF().height()
+
+        image = QImage(width, height, QImage.Format_ARGB32)
+        image.fill(Qt.transparent)
+
+        p = QPainter(image)
+        p.setRenderHint(QPainter.Antialiasing, False)
+        svgr.render(p)
+        p.end()
+
+        res = image.save(rendered_file_path, 'png')
+        if not res:
+            os.unlink(rendered_file_path)
+
     """QGIS Server WMS Tests for GetPrint request"""
 
     def test_wms_getprint_basic(self):
@@ -107,6 +239,22 @@ def test_wms_getprint_basic(self):
         r, h = self._result(self._execute_request(qs))
         self._img_diff_error(r, h, "WMS_GetPrint_Basic", outputJpg=True)
 
+        # Output PDF
+        qs = "?" + "&".join(["%s=%s" % i for i in list({
+            "MAP": urllib.parse.quote(self.projectPath),
+            "SERVICE": "WMS",
+            "VERSION": "1.1.1",
+            "REQUEST": "GetPrint",
+            "TEMPLATE": "layoutA4",
+            "FORMAT": "pdf",
+            "map0:EXTENT": "-33626185.498,-13032965.185,33978427.737,16020257.031",
+            "LAYERS": "Country,Hello",
+            "CRS": "EPSG:3857"
+        }.items())])
+
+        r, h = self._result(self._execute_request(qs))
+        self._pdf_diff_error(r, h, "WMS_GetPrint_Basic_Pdf", dpi=300)
+
     def test_wms_getprint_style(self):
         # default style
         qs = "?" + "&".join(["%s=%s" % i for i in list({
@@ -312,6 +460,24 @@ def test_wms_getprint_selection(self):
         r, h = self._result(self._execute_request(qs))
         self._img_diff_error(r, h, "WMS_GetPrint_Selection")
 
+        # Output PDF
+        qs = "?" + "&".join(["%s=%s" % i for i in list({
+            "MAP": urllib.parse.quote(self.projectPath),
+            "SERVICE": "WMS",
+            "VERSION": "1.1.1",
+            "REQUEST": "GetPrint",
+            "TEMPLATE": "layoutA4",
+            "FORMAT": "pdf",
+            "LAYERS": "Country,Hello",
+            "map0:EXTENT": "-33626185.498,-13032965.185,33978427.737,16020257.031",
+            "map0:LAYERS": "Country,Hello",
+            "CRS": "EPSG:3857",
+            "SELECTION": "Country: 4"
+        }.items())])
+
+        r, h = self._result(self._execute_request(qs))
+        self._pdf_diff_error(r, h, "WMS_GetPrint_Selection_Pdf", dpi=300)
+
     def test_wms_getprint_opacity(self):
         qs = "?" + "&".join(["%s=%s" % i for i in list({
             "MAP": urllib.parse.quote(self.projectPath),