Add missing "interval" and "curvepoint" modes to data defined line marker (fix #16212)

Author: nyalldawson

src/core/symbology-ng/qgslinesymbollayer.cpp

@@ -829,7 +829,11 @@ void QgsMarkerLineSymbolLayer::renderPolyline( const QPolygonF& points, QgsSymbo
     if ( exprVal.isValid() )
     {
       QString placementString = exprVal.toString();
-      if ( placementString.compare( QLatin1String( "vertex" ), Qt::CaseInsensitive ) == 0 )
+      if ( placementString.compare( QLatin1String( "interval" ), Qt::CaseInsensitive ) == 0 )
+      {
+        placement = Interval;
+      }
+      else if ( placementString.compare( QLatin1String( "vertex" ), Qt::CaseInsensitive ) == 0 )
       {
         placement = Vertex;
       }

src/core/symbology-ng/qgssymbollayer.cpp

@@ -77,7 +77,7 @@ void QgsSymbolLayer::initPropertyDefinitions()
     { QgsSymbolLayer::PropertyAlpha, QgsPropertyDefinition( "alpha", QObject::tr( "Opacity" ), QgsPropertyDefinition::Double0To1 )},
     { QgsSymbolLayer::PropertyCustomDash, QgsPropertyDefinition( "customDash", QgsPropertyDefinition::DataTypeString, QObject::tr( "Custom dash pattern" ), QObject::tr( "[<b><dash>;<space></b>] e.g. '8;2;1;2'" ) )},
     { QgsSymbolLayer::PropertyCapStyle, QgsPropertyDefinition( "capStyle", QObject::tr( "Line cap style" ), QgsPropertyDefinition::CapStyle )},
-    { QgsSymbolLayer::PropertyPlacement, QgsPropertyDefinition( "placement", QgsPropertyDefinition::DataTypeString, QObject::tr( "Marker placement" ), QObject::tr( "string " ) + "[<b>vertex</b>|<b>lastvertex</b>|<b>firstvertex</b>|<b>centerpoint</b>]" )},
+    { QgsSymbolLayer::PropertyPlacement, QgsPropertyDefinition( "placement", QgsPropertyDefinition::DataTypeString, QObject::tr( "Marker placement" ), QObject::tr( "string " ) + "[<b>interval</b>|<b>vertex</b>|<b>lastvertex</b>|<b>firstvertex</b>|<b>centerpoint</b>|<b>curvepoint</b>]" )},
     { QgsSymbolLayer::PropertyInterval, QgsPropertyDefinition( "interval", QObject::tr( "Marker interval" ), QgsPropertyDefinition::DoublePositive )},
     { QgsSymbolLayer::PropertyOffsetAlongLine, QgsPropertyDefinition( "offsetAlongLine", QObject::tr( "Offset along line" ), QgsPropertyDefinition::DoublePositive )},
     { QgsSymbolLayer::PropertyHorizontalAnchor, QgsPropertyDefinition( "hAnchor", QObject::tr( "Horizontal anchor point" ), QgsPropertyDefinition::HorizontalAnchor )},