When DD rotation fails to evaluate, fallback to static value

The old behavior was to always fall back to 0 in case of a failing expression. Which made it hard to create a proper legend in some cases. E.g. if you had two symbol layers with the following expressions for their rotation "orientation" And 90 + "orientation" which would be two orthogonal symbol layers (e.g. denote a right angle), rotated by an orientation field. Now in the legend (and symbol preview), both layers would be shown with a rotation of 0, because there is no associated feature with a field orientation. The new behavior is to fallback to the static, configured values which makes it very intuitive to configure the legend for these cases.
qgis · Dec 8, 2019 · 348d216 · 348d216
1 parent fc5c95c
commit 348d216
Showing 1 changed file with 10 additions and 6 deletions.
diff --git a/src/core/symbology/qgsmarkersymbollayer.cpp b/src/core/symbology/qgsmarkersymbollayer.cpp
@@ -648,15 +648,17 @@ void QgsSimpleMarkerSymbolLayerBase::calculateOffsetAndRotation( QgsSymbolRender
   //angle
   bool ok = true;
   angle = mAngle + mLineAngle;
-  bool usingDataDefinedRotation = false;
   if ( mDataDefinedProperties.isActive( QgsSymbolLayer::PropertyAngle ) )
   {
     context.setOriginalValueVariable( angle );
     angle = mDataDefinedProperties.valueAsDouble( QgsSymbolLayer::PropertyAngle, context.renderContext().expressionContext(), mAngle, &ok ) + mLineAngle;
-    usingDataDefinedRotation = ok;
+
+    // If the expression evaluation was not successful, fallback to static value
+    if ( !ok )
+      angle = mAngle + mLineAngle;
   }
 
-  hasDataDefinedRotation = context.renderHints() & QgsSymbol::DynamicRotation || usingDataDefinedRotation;
+  hasDataDefinedRotation = context.renderHints() & QgsSymbol::DynamicRotation;
   if ( hasDataDefinedRotation )
   {
     // For non-point markers, "dataDefinedRotation" means following the
@@ -3083,15 +3085,17 @@ void QgsFontMarkerSymbolLayer::calculateOffsetAndRotation( QgsSymbolRenderContex
   //angle
   bool ok = true;
   angle = mAngle + mLineAngle;
-  bool usingDataDefinedRotation = false;
   if ( mDataDefinedProperties.isActive( QgsSymbolLayer::PropertyAngle ) )
   {
     context.setOriginalValueVariable( angle );
     angle = mDataDefinedProperties.valueAsDouble( QgsSymbolLayer::PropertyAngle, context.renderContext().expressionContext(), mAngle, &ok ) + mLineAngle;
-    usingDataDefinedRotation = ok;
+
+    // If the expression evaluation was not successful, fallback to static value
+    if ( !ok )
+      angle = mAngle + mLineAngle;
   }
 
-  hasDataDefinedRotation = context.renderHints() & QgsSymbol::DynamicRotation || usingDataDefinedRotation;
+  hasDataDefinedRotation = context.renderHints() & QgsSymbol::DynamicRotation;
   if ( hasDataDefinedRotation )
   {
     // For non-point markers, "dataDefinedRotation" means following the