Fix rendering offset lines as part of fill symbol (outside of

vector layers) results in broken offset outline

python/core/symbology-ng/qgssymbol.sip

@@ -357,6 +357,9 @@ class QgsSymbolRenderContext
     //! Current feature being rendered - may be null
     const QgsFeature* feature() const;
 
+    void setOriginalGeometryType( QgsWkbTypes::GeometryType type );
+    QgsWkbTypes::GeometryType originalGeometryType() const;
+
     //! Fields of the layer. Currently only available in startRender() calls
     //! to allow symbols with data-defined properties prepare the expressions
     //! (other times fields() returns null)

src/core/symbology-ng/qgslinesymbollayer.cpp

@@ -328,7 +328,7 @@ void QgsSimpleLineSymbolLayer::renderPolyline( const QPolygonF& points, QgsSymbo
   else
   {
     double scaledOffset = context.renderContext().convertToPainterUnits( offset, mOffsetUnit, mOffsetMapUnitScale );
-    QList<QPolygonF> mline = ::offsetLine( points, scaledOffset, context.feature() ? context.feature()->geometry().type() : QgsWkbTypes::LineGeometry );
+    QList<QPolygonF> mline = ::offsetLine( points, scaledOffset, context.originalGeometryType() != QgsWkbTypes::UnknownGeometry ? context.originalGeometryType() : QgsWkbTypes::LineGeometry );
     for ( int part = 0; part < mline.count(); ++part )
     {
 #if 0
@@ -876,7 +876,7 @@ void QgsMarkerLineSymbolLayer::renderPolyline( const QPolygonF& points, QgsSymbo
   else
   {
     context.renderContext().setGeometry( nullptr ); //always use segmented geometry with offset
-    QList<QPolygonF> mline = ::offsetLine( points, context.renderContext().convertToPainterUnits( offset, mOffsetUnit, mOffsetMapUnitScale ), context.feature() ? context.feature()->geometry().type() : QgsWkbTypes::LineGeometry );
+    QList<QPolygonF> mline = ::offsetLine( points, context.renderContext().convertToPainterUnits( offset, mOffsetUnit, mOffsetMapUnitScale ), context.originalGeometryType() != QgsWkbTypes::UnknownGeometry ? context.originalGeometryType() : QgsWkbTypes::LineGeometry );
 
     for ( int part = 0; part < mline.count(); ++part )
     {

src/core/symbology-ng/qgssymbol.cpp

@@ -1629,6 +1629,7 @@ void QgsLineSymbol::renderPolyline( const QPolygonF& points, const QgsFeature* f
   //save old painter
   QPainter* renderPainter = context.painter();
   QgsSymbolRenderContext symbolContext( context, outputUnit(), mAlpha, selected, mRenderHints, f, QgsFields(), mapUnitScale() );
+  symbolContext.setOriginalGeometryType( QgsWkbTypes::LineGeometry );
   symbolContext.setGeometryPartCount( symbolRenderContext()->geometryPartCount() );
   symbolContext.setGeometryPartNum( symbolRenderContext()->geometryPartNum() );
 
@@ -1709,6 +1710,7 @@ QgsFillSymbol::QgsFillSymbol( const QgsSymbolLayerList& layers )
 void QgsFillSymbol::renderPolygon( const QPolygonF& points, QList<QPolygonF>* rings, const QgsFeature* f, QgsRenderContext& context, int layerIdx, bool selected )
 {
   QgsSymbolRenderContext symbolContext( context, outputUnit(), mAlpha, selected, mRenderHints, f, QgsFields(), mapUnitScale() );
+  symbolContext.setOriginalGeometryType( QgsWkbTypes::PolygonGeometry );
   symbolContext.setGeometryPartCount( symbolRenderContext()->geometryPartCount() );
   symbolContext.setGeometryPartNum( symbolRenderContext()->geometryPartNum() );
 

src/core/symbology-ng/qgssymbol.h

@@ -434,6 +434,23 @@ class CORE_EXPORT QgsSymbolRenderContext
     //! Current feature being rendered - may be null
     const QgsFeature* feature() const { return mFeature; }
 
+    /**
+     * Sets the geometry type for the original feature geometry being rendered.
+     * @see originalGeometryType()
+     * @note added in QGIS 3.0
+     */
+    void setOriginalGeometryType( QgsWkbTypes::GeometryType type ) { mOriginalGeometryType = type; }
+
+    /**
+     * Returns the geometry type for the original feature geometry being rendered. This can be
+     * useful if symbol layers alter their appearance based on geometry type - eg offsetting a
+     * simple line style will look different if the simple line is rendering a polygon feature
+     * (a closed buffer) vs a line feature (an unclosed offset line).
+     * @see originalGeometryType()
+     * @note added in QGIS 3.0
+     */
+    QgsWkbTypes::GeometryType originalGeometryType() const { return mOriginalGeometryType; }
+
     //! Fields of the layer. Currently only available in startRender() calls
     //! to allow symbols with data-defined properties prepare the expressions
     //! (other times fields() returns null)
@@ -494,6 +511,7 @@ class CORE_EXPORT QgsSymbolRenderContext
     QgsFields mFields;
     int mGeometryPartCount;
     int mGeometryPartNum;
+    QgsWkbTypes::GeometryType mOriginalGeometryType = QgsWkbTypes::UnknownGeometry;
 
 
     QgsSymbolRenderContext( const QgsSymbolRenderContext& rh );

tests/src/python/CMakeLists.txt

@@ -47,6 +47,7 @@ ADD_PYTHON_TEST(PyQgsExpression test_qgsexpression.py)
 ADD_PYTHON_TEST(PyQgsExpressionLineEdit test_qgsexpressionlineedit.py)
 ADD_PYTHON_TEST(PyQgsFeature test_qgsfeature.py)
 ADD_PYTHON_TEST(PyQgsFieldFormattersTest test_qgsfieldformatters.py)
+ADD_PYTHON_TEST(PyQgsFillSymbolLayers test_qgsfillsymbollayers.py)
 ADD_PYTHON_TEST(PyQgsProject test_qgsproject.py)
 ADD_PYTHON_TEST(PyQgsFeatureIterator test_qgsfeatureiterator.py)
 ADD_PYTHON_TEST(PyQgsField test_qgsfield.py)
@@ -61,6 +62,7 @@ ADD_PYTHON_TEST(PyQgsGeometryValidator test_qgsgeometryvalidator.py)
 ADD_PYTHON_TEST(PyQgsGraduatedSymbolRenderer test_qgsgraduatedsymbolrenderer.py)
 ADD_PYTHON_TEST(PyQgsInterval test_qgsinterval.py)
 ADD_PYTHON_TEST(PyQgsJSONUtils test_qgsjsonutils.py)
+ADD_PYTHON_TEST(PyQgsLineSymbolLayers test_qgslinesymbollayers.py)
 ADD_PYTHON_TEST(PyQgsMapCanvasAnnotationItem test_qgsmapcanvasannotationitem.py)
 ADD_PYTHON_TEST(PyQgsMapLayerModel test_qgsmaplayermodel.py)
 ADD_PYTHON_TEST(PyQgsMapUnitScale test_qgsmapunitscale.py)

tests/src/python/test_qgsfillsymbollayers.py

@@ -0,0 +1,94 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsFillSymbolLayers.
+
+.. note:: 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.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '2017-01'
+__copyright__ = 'Copyright 2017, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+
+import qgis  # NOQA
+
+from qgis.testing import unittest
+from qgis.PyQt.QtCore import QDir
+from qgis.PyQt.QtGui import (QImage,
+                             QPainter,
+                             QColor)
+from qgis.core import (QgsRenderChecker,
+                       QgsSimpleLineSymbolLayer,
+                       QgsMapSettings,
+                       QgsFillSymbol,
+                       QgsGeometry,
+                       QgsFeature,
+                       QgsRenderContext)
+
+
+class TestQgsFillSymbolLayers(unittest.TestCase):
+
+    def setUp(self):
+        self.report = "<h1>Python QgsFillSymbolLayer Tests</h1>\n"
+
+    def tearDown(self):
+        report_file_path = "%s/qgistest.html" % QDir.tempPath()
+        with open(report_file_path, 'a') as report_file:
+            report_file.write(self.report)
+
+    def imageCheck(self, name, reference_image, image):
+        self.report += "<h2>Render {}</h2>\n".format(name)
+        temp_dir = QDir.tempPath() + '/'
+        file_name = temp_dir + 'symbollayer_' + name + ".png"
+        image.save(file_name, "PNG")
+        checker = QgsRenderChecker()
+        checker.setControlPathPrefix("symbol_layer")
+        checker.setControlName("expected_" + reference_image)
+        checker.setRenderedImage(file_name)
+        checker.setColorTolerance(2)
+        result = checker.compareImages(name, 0)
+        self.report += checker.report()
+        print((self.report))
+        return result
+
+    def testSimpleLineWithOffset(self):
+        """ test that rendering a polygon with simple line symbol with offset results in closed line"""
+        layer = QgsSimpleLineSymbolLayer()
+        layer.setOffset(-1)
+
+        symbol = QgsFillSymbol()
+        symbol.changeSymbolLayer(0, layer)
+
+        image = QImage(200, 200, QImage.Format_RGB32)
+        painter = QPainter()
+        ms = QgsMapSettings()
+
+        geom = QgsGeometry.fromWkt('Polygon((0 0, 10 0, 10 10, 0 10, 0 0))')
+        f = QgsFeature()
+        f.setGeometry(geom)
+
+        extent = geom.geometry().boundingBox()
+        # buffer extent by 10%
+        extent = extent.buffer((extent.height() + extent.width()) / 20.0)
+
+        ms.setExtent(extent)
+        ms.setOutputSize(image.size())
+        context = QgsRenderContext.fromMapSettings(ms)
+        context.setPainter(painter)
+        context.setScaleFactor(96 / 25.4)  # 96 DPI
+
+        painter.begin(image)
+        image.fill(QColor(255, 255, 255))
+
+        symbol.startRender(context)
+        symbol.renderFeature(f, context)
+        symbol.stopRender(context)
+        painter.end()
+
+        self.assertTrue(self.imageCheck('symbol_layer', 'fill_simpleline_offset', image))
+
+if __name__ == '__main__':
+    unittest.main()

tests/src/python/test_qgslinesymbollayers.py

@@ -0,0 +1,94 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsLineSymbolLayers.
+
+.. note:: 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.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '2017-01'
+__copyright__ = 'Copyright 2017, The QGIS Project'
+# This will get replaced with a git SHA1 when you do a git archive
+__revision__ = '$Format:%H$'
+
+
+import qgis  # NOQA
+
+from qgis.testing import unittest
+from qgis.PyQt.QtCore import QDir
+from qgis.PyQt.QtGui import (QImage,
+                             QPainter,
+                             QColor)
+from qgis.core import (QgsRenderChecker,
+                       QgsSimpleLineSymbolLayer,
+                       QgsMapSettings,
+                       QgsLineSymbol,
+                       QgsGeometry,
+                       QgsFeature,
+                       QgsRenderContext)
+
+
+class TestQgsLineSymbolLayers(unittest.TestCase):
+
+    def setUp(self):
+        self.report = "<h1>Python QgsLineSymbolLayer Tests</h1>\n"
+
+    def tearDown(self):
+        report_file_path = "%s/qgistest.html" % QDir.tempPath()
+        with open(report_file_path, 'a') as report_file:
+            report_file.write(self.report)
+
+    def imageCheck(self, name, reference_image, image):
+        self.report += "<h2>Render {}</h2>\n".format(name)
+        temp_dir = QDir.tempPath() + '/'
+        file_name = temp_dir + 'symbollayer_' + name + ".png"
+        image.save(file_name, "PNG")
+        checker = QgsRenderChecker()
+        checker.setControlPathPrefix("symbol_layer")
+        checker.setControlName("expected_" + reference_image)
+        checker.setRenderedImage(file_name)
+        checker.setColorTolerance(2)
+        result = checker.compareImages(name, 0)
+        self.report += checker.report()
+        print((self.report))
+        return result
+
+    def testSimpleLineWithOffset(self):
+        """ test that rendering a simple line symbol with offset"""
+        layer = QgsSimpleLineSymbolLayer()
+        layer.setOffset(1)
+
+        symbol = QgsLineSymbol()
+        symbol.changeSymbolLayer(0, layer)
+
+        image = QImage(200, 200, QImage.Format_RGB32)
+        painter = QPainter()
+        ms = QgsMapSettings()
+
+        geom = QgsGeometry.fromWkt('LineString (0 0, 10 0, 10 10, 0 10, 0 0)')
+        f = QgsFeature()
+        f.setGeometry(geom)
+
+        extent = geom.geometry().boundingBox()
+        # buffer extent by 10%
+        extent = extent.buffer((extent.height() + extent.width()) / 20.0)
+
+        ms.setExtent(extent)
+        ms.setOutputSize(image.size())
+        context = QgsRenderContext.fromMapSettings(ms)
+        context.setPainter(painter)
+        context.setScaleFactor(96 / 25.4)  # 96 DPI
+
+        painter.begin(image)
+        image.fill(QColor(255, 255, 255))
+
+        symbol.startRender(context)
+        symbol.renderFeature(f, context)
+        symbol.stopRender(context)
+        painter.end()
+
+        self.assertTrue(self.imageCheck('symbol_layer', 'simpleline_offset', image))
+
+if __name__ == '__main__':
+    unittest.main()