[feature] Allow offset along line to be specified in percent for

marker line and hash line symbol layer types Offsets are treated as percent of overall line length
qgis · Dec 14, 2021 · aac0432 · aac0432
1 parent 0a1731a
commit aac0432
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Showing 5 changed files with 94 additions and 4 deletions.
diff --git a/src/core/symbology/qgslinesymbollayer.cpp b/src/core/symbology/qgslinesymbollayer.cpp
@@ -1678,7 +1678,31 @@ void QgsTemplatedLineSymbolLayerBase::renderPolylineInterval( const QPolygonF &p
   if ( painterUnitInterval < 0 )
     return;
 
-  double painterUnitOffsetAlongLine = rc.convertToPainterUnits( offsetAlongLine, offsetAlongLineUnit(), offsetAlongLineMapUnitScale() );
+  double painterUnitOffsetAlongLine = 0;
+
+  // only calculated if we need it!
+  double totalLength = -1;
+
+  if ( !qgsDoubleNear( offsetAlongLine, 0 ) )
+  {
+    totalLength = QgsSymbolLayerUtils::polylineLength( points );
+    switch ( offsetAlongLineUnit() )
+    {
+      case QgsUnitTypes::RenderMillimeters:
+      case QgsUnitTypes::RenderMapUnits:
+      case QgsUnitTypes::RenderPixels:
+      case QgsUnitTypes::RenderPoints:
+      case QgsUnitTypes::RenderInches:
+      case QgsUnitTypes::RenderUnknownUnit:
+      case QgsUnitTypes::RenderMetersInMapUnits:
+        painterUnitOffsetAlongLine = rc.convertToPainterUnits( offsetAlongLine, offsetAlongLineUnit(), offsetAlongLineMapUnitScale() );
+        break;
+      case QgsUnitTypes::RenderPercentage:
+        painterUnitOffsetAlongLine = offsetAlongLine / 100 * totalLength;
+        break;
+    }
+  }
+
   if ( offsetAlongLineUnit() == QgsUnitTypes::RenderMetersInMapUnits && rc.flags() & Qgis::RenderContextFlag::RenderSymbolPreview )
   {
     // rendering for symbol previews -- an offset in meters in map units can't be calculated, so treat the size as millimeters
@@ -1825,10 +1849,29 @@ void QgsTemplatedLineSymbolLayerBase::renderPolylineVertex( const QPolygonF &poi
     context.setOriginalValueVariable( mOffsetAlongLine );
     offsetAlongLine = mDataDefinedProperties.valueAsDouble( QgsSymbolLayer::PropertyOffsetAlongLine, context.renderContext().expressionContext(), mOffsetAlongLine );
   }
+
+  // only calculated if we need it!!
+  double totalLength = -1;
   if ( !qgsDoubleNear( offsetAlongLine, 0.0 ) )
   {
+    totalLength = QgsSymbolLayerUtils::polylineLength( points );
+
     //scale offset along line
-    offsetAlongLine = rc.convertToPainterUnits( offsetAlongLine, offsetAlongLineUnit(), offsetAlongLineMapUnitScale() );
+    switch ( offsetAlongLineUnit() )
+    {
+      case QgsUnitTypes::RenderMillimeters:
+      case QgsUnitTypes::RenderMapUnits:
+      case QgsUnitTypes::RenderPixels:
+      case QgsUnitTypes::RenderPoints:
+      case QgsUnitTypes::RenderInches:
+      case QgsUnitTypes::RenderUnknownUnit:
+      case QgsUnitTypes::RenderMetersInMapUnits:
+        offsetAlongLine = rc.convertToPainterUnits( offsetAlongLine, offsetAlongLineUnit(), offsetAlongLineMapUnitScale() );
+        break;
+      case QgsUnitTypes::RenderPercentage:
+        offsetAlongLine = offsetAlongLine / 100 * totalLength;
+        break;
+    }
   }
 
   if ( qgsDoubleNear( offsetAlongLine, 0.0 ) && context.renderContext().geometry()

diff --git a/src/gui/symbology/qgssymbollayerwidget.cpp b/src/gui/symbology/qgssymbollayerwidget.cpp
@@ -1902,7 +1902,7 @@ QgsMarkerLineSymbolLayerWidget::QgsMarkerLineSymbolLayerWidget( QgsVectorLayer *
   mOffsetUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
   mOffsetAlongLineUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
-                                        << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
+                                        << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches << QgsUnitTypes::RenderPercentage );
   mAverageAngleUnit->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
 
@@ -2155,7 +2155,7 @@ QgsHashedLineSymbolLayerWidget::QgsHashedLineSymbolLayerWidget( QgsVectorLayer *
   mOffsetUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
   mOffsetAlongLineUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
-                                        << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
+                                        << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches << QgsUnitTypes::RenderPercentage );
   mAverageAngleUnit->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels
                                << QgsUnitTypes::RenderPoints << QgsUnitTypes::RenderInches );
   mHashLengthUnitWidget->setUnits( QgsUnitTypes::RenderUnitList() << QgsUnitTypes::RenderMillimeters << QgsUnitTypes::RenderMetersInMapUnits << QgsUnitTypes::RenderMapUnits << QgsUnitTypes::RenderPixels

diff --git a/tests/src/python/test_qgsmarkerlinesymbollayer.py b/tests/src/python/test_qgsmarkerlinesymbollayer.py
@@ -680,6 +680,53 @@ def testNoPoint(self):
         rendered_image = self.renderGeometry(s, g)
         assert self.imageCheck('markerline_none', 'markerline_none', rendered_image)
 
+    def testFirstVertexOffsetPercentage(self):
+        s = QgsLineSymbol()
+        s.deleteSymbolLayer(0)
+
+        marker_line = QgsMarkerLineSymbolLayer(True)
+        marker_line.setPlacements(Qgis.MarkerLinePlacement.FirstVertex)
+        marker_line.setOffsetAlongLine(10)
+        marker_line.setOffsetAlongLineUnit(QgsUnitTypes.RenderPercentage)
+        marker = QgsSimpleMarkerSymbolLayer(QgsSimpleMarkerSymbolLayer.Circle, 4)
+        marker.setColor(QColor(255, 0, 0, 100))
+        marker.setStrokeStyle(Qt.NoPen)
+        marker_symbol = QgsMarkerSymbol()
+        marker_symbol.changeSymbolLayer(0, marker)
+        marker_line.setSubSymbol(marker_symbol)
+        line_symbol = QgsLineSymbol()
+        line_symbol.changeSymbolLayer(0, marker_line)
+
+        s.appendSymbolLayer(marker_line.clone())
+
+        g = QgsGeometry.fromWkt('LineString(0 0, 0 10, 10 10)')
+        rendered_image = self.renderGeometry(s, g)
+        assert self.imageCheck('markerline_first_offset_percent', 'markerline_first_offset_percent', rendered_image)
+
+    def testIntervalOffsetPercentage(self):
+        s = QgsLineSymbol()
+        s.deleteSymbolLayer(0)
+
+        marker_line = QgsMarkerLineSymbolLayer(True)
+        marker_line.setPlacements(Qgis.MarkerLinePlacement.Interval)
+        marker_line.setInterval(6)
+        marker_line.setOffsetAlongLine(50)
+        marker_line.setOffsetAlongLineUnit(QgsUnitTypes.RenderPercentage)
+        marker = QgsSimpleMarkerSymbolLayer(QgsSimpleMarkerSymbolLayer.Circle, 4)
+        marker.setColor(QColor(255, 0, 0, 100))
+        marker.setStrokeStyle(Qt.NoPen)
+        marker_symbol = QgsMarkerSymbol()
+        marker_symbol.changeSymbolLayer(0, marker)
+        marker_line.setSubSymbol(marker_symbol)
+        line_symbol = QgsLineSymbol()
+        line_symbol.changeSymbolLayer(0, marker_line)
+
+        s.appendSymbolLayer(marker_line.clone())
+
+        g = QgsGeometry.fromWkt('LineString(0 0, 0 10, 10 10)')
+        rendered_image = self.renderGeometry(s, g)
+        assert self.imageCheck('markerline_interval_offset_percent', 'markerline_interval_offset_percent', rendered_image)
+
     def testCenterSegment(self):
         s = QgsLineSymbol()
         s.deleteSymbolLayer(0)

diff --git a/...ed_markerline_first_offset_percent/expected_markerline_first_offset_percent.png b/...ed_markerline_first_offset_percent/expected_markerline_first_offset_percent.png
diff --git a/...kerline_interval_offset_percent/expected_markerline_interval_offset_percent.png b/...kerline_interval_offset_percent/expected_markerline_interval_offset_percent.png