xpose single vector tile encoding method

qgis · Sep 7, 2021 · f7cc194 · f7cc194
1 parent e850195
commit f7cc194
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diff --git a/python/core/auto_generated/vectortile/qgsvectortilewriter.sip.in b/python/core/auto_generated/vectortile/qgsvectortilewriter.sip.in
@@ -174,6 +174,20 @@ an empty string if writing was successful.
     QgsRectangle fullExtent() const;
 %Docstring
 Returns calculated extent that combines extent of all input layers
+%End
+
+    QByteArray writeSingleTile( QgsTileXYZ tileID, QgsFeedback *feedback = 0, int buffer = 256, int resolution = 4096 ) const;
+%Docstring
+Encodes single MVT tile
+
+:param tileID: Tile identifier
+:param feedback: optional, provide cancellation functionality
+:param resolution: the resolution of coordinates of geometries within the tile. The default is 4096
+:param buffer: size of the buffer zone around tile edges in integer tile coordinates. The default is 256 (~6%)
+
+Returns a QByteArray with the encoded data
+
+.. versionadded:: 3.22
 %End
 
 };

diff --git a/src/core/vectortile/qgsvectortilewriter.cpp b/src/core/vectortile/qgsvectortilewriter.cpp
@@ -296,3 +296,26 @@ QString QgsVectorTileWriter::mbtilesJsonSchema()
   rootObj["vector_layers"] = arrayLayers;
   return QString::fromStdString( QgsJsonUtils::jsonFromVariant( rootObj ).dump() );
 }
+
+
+QByteArray QgsVectorTileWriter::writeSingleTile( QgsTileXYZ tileID, QgsFeedback *feedback, int buffer, int resolution ) const
+{
+  int zoomLevel = tileID.zoomLevel();
+
+  QgsVectorTileMVTEncoder encoder( tileID );
+  encoder.setTileBuffer( buffer );
+  encoder.setResolution( resolution );
+  encoder.setTransformContext( mTransformContext );
+
+  for ( const QgsVectorTileWriter::Layer &layer : std::as_const( mLayers ) )
+  {
+    if ( ( layer.minZoom() >= 0 && zoomLevel < layer.minZoom() ) ||
+         ( layer.maxZoom() >= 0 && zoomLevel > layer.maxZoom() ) )
+      continue;
+
+    encoder.addLayer( layer.layer(), feedback, layer.filterExpression(), layer.layerName() );
+  }
+
+  return encoder.encode();
+}
+
diff --git a/src/core/vectortile/qgsvectortilewriter.h b/src/core/vectortile/qgsvectortilewriter.h
@@ -165,6 +165,20 @@ class CORE_EXPORT QgsVectorTileWriter
     //! Returns calculated extent that combines extent of all input layers
     QgsRectangle fullExtent() const;
 
+    /**
+     * Encodes single MVT tile
+     *
+     * \param tileID Tile identifier
+     * \param feedback  optional, provide cancellation functionality
+     * \param resolution the resolution of coordinates of geometries within the tile. The default is 4096
+     * \param buffer size of the buffer zone around tile edges in integer tile coordinates. The default is 256 (~6%)
+     *
+     * Returns a QByteArray with the encoded data
+     *
+     * \since QGIS 3.22
+    */
+    QByteArray writeSingleTile( QgsTileXYZ tileID, QgsFeedback *feedback = nullptr, int buffer = 256, int resolution = 4096 ) const;
+
   private:
     bool writeTileFileXYZ( const QString &sourcePath, QgsTileXYZ tileID, const QgsTileMatrix &tileMatrix, const QByteArray &tileData );
     QString mbtilesJsonSchema();

diff --git a/tests/src/python/CMakeLists.txt b/tests/src/python/CMakeLists.txt
@@ -372,6 +372,7 @@ ADD_PYTHON_TEST(PyQgsSelectiveMasking test_selective_masking.py)
 ADD_PYTHON_TEST(PyQgsRelationEditorWidgetRegistry test_qgsrelationeditorwidgetregistry.py)
 ADD_PYTHON_TEST(PyQgsActionWidgetWrapper test_qgsactionwidgetwrapper.py)
 ADD_PYTHON_TEST(PyQgsAttributeEditorAction test_qgsattributeeditoraction.py)
+ADD_PYTHON_TEST(PyQgsVectorTile test_qgsvectortile.py)
 
 if (NOT WIN32)
   ADD_PYTHON_TEST(PyQgsLogger test_qgslogger.py)

diff --git a/tests/src/python/test_qgsvectortile.py b/tests/src/python/test_qgsvectortile.py
@@ -0,0 +1,92 @@
+# -*- coding: utf-8 -*-
+'''
+test_vectortile.py
+--------------------------------------
+               Date                 : September 2021
+               Copyright            : (C) 2021 David Marteau
+               email                : david dot marteau at 3liz dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+'''
+
+import qgis  # NOQA
+import tempfile
+import shutil
+
+from qgis.testing import unittest, start_app
+from utilities import unitTestDataPath
+
+from qgis.PyQt.QtCore import QUrl
+from qgis.core import (QgsVectorLayer,
+                       QgsVectorTileWriter,
+                       QgsDataSourceUri,
+                       QgsTileXYZ)
+
+from pathlib import Path
+
+TEST_DATA_PATH = Path(unitTestDataPath())
+
+
+start_app()
+
+
+class TestVectorTile(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls.tempdir = Path(tempfile.mkdtemp())
+
+    @classmethod
+    def tearDownClass(cls):
+        shutil.rmtree(cls.tempdir, True)
+
+    def setUp(self):
+        """Run before each test."""
+        pass
+
+    def tearDown(self):
+        """Run after each test."""
+        pass
+
+    def testSingleTileEncode(self):
+        """ Test vector tile encoding from python
+        """
+        vlPoints = QgsVectorLayer(str(TEST_DATA_PATH / "points.shp"), "points", "ogr")
+        vlLines = QgsVectorLayer(str(TEST_DATA_PATH / "lines.shp"), "lines", "ogr")
+        vlPolys = QgsVectorLayer(str(TEST_DATA_PATH / "polys.shp"), "polys", "ogr")
+
+        layers = [QgsVectorTileWriter.Layer(vl) for vl in (vlPoints, vlLines, vlPolys)]
+
+        writer = QgsVectorTileWriter()
+        writer.setMaxZoom(3)
+        writer.setLayers(layers)
+
+        data = writer.writeSingleTile(QgsTileXYZ(0, 0, 0))
+
+        ds = QgsDataSourceUri()
+        ds.setParam("type", "xyz")
+        ds.setParam("url", (self.tempdir / "{z}-{x}-{y}.pbf").as_uri())
+
+        # Create pbf files
+        writer.setDestinationUri(ds.encodedUri().data().decode())
+        res = writer.writeTiles()
+        self.assertEqual(writer.errorMessage(), "")
+        self.assertTrue(res)
+
+        # Compare encoded data to written file
+        # Read data from file
+        with (self.tempdir / "0-0-0.pbf").open("rb") as fp:
+            output = fp.read()
+
+        # Compare binary data
+        self.assertEqual(ascii(data.data()), ascii(output))
+
+
+if __name__ == '__main__':
+    unittest.main()