Fix saving of polygons' fill rule

Up until now, the fill rule of a polygon was always saved as even-odd,
despite the fact that in most if not all cases, polygons are drawn with
winding fill within OpenBoard.
Saving is now fixed, but there is no way to know upon loading whether
the polygon was correctly saved or whether; so for now, we just set the
fill rule to Winding when loading a polygon.

src/adaptors/UBSvgSubsetAdaptor.cpp

@@ -1599,6 +1599,8 @@ void UBSvgSubsetAdaptor::UBSvgSubsetWriter::polygonItemToSvgPolygon(UBGraphicsPo
 
         if (polygonItem->fillRule() == Qt::OddEvenFill)
             mXmlWriter.writeAttribute("fill-rule", "evenodd");
+        else
+            mXmlWriter.writeAttribute("fill-rule", "winding");
 
         if (!groupHoldsInfo)
         {
@@ -1720,6 +1722,27 @@ UBGraphicsPolygonItem* UBSvgSubsetAdaptor::UBSvgSubsetReader::polygonItemFromPol
         color.setAlphaF(opacity);
         polygonItem->setColorOnLightBackground(color);
     }
+
+    /*
+
+    Unfortunately the fill rule was never saved correctly until OpenBoard v1.4,
+    before then, it was always saved as even-odd. So we can't load it safely here.
+    Saving is now fixed, but any old documents would be loaded incorrectly if the code
+    below is used. It should be activated at some point in the future though.
+
+    QStringRef fillRule = mXmlReader.attributes().value("fill-rule");
+
+    if (!fillRule.isNull()) {
+        QString value = fillRule.toString();
+
+        if (value == "evenodd")
+            polygonItem->setFillRule(Qt::OddEvenFill);
+        else
+            polygonItem->setFillRule(Qt::WindingFill);
+    }
+    */
+    polygonItem->setFillRule(Qt::WindingFill);
+
     return polygonItem;
 
 }

src/domain/UBGraphicsPolygonItem.cpp

@@ -171,6 +171,7 @@ void UBGraphicsPolygonItem::copyItemParameters(UBItem *copy) const
         cp->setBrush(this->brush());
         cp->setPen(this->pen());
         cp->mHasAlpha = this->mHasAlpha;
+        cp->setFillRule(this->fillRule());
 
         cp->setColorOnDarkBackground(this->colorOnDarkBackground());
         cp->setColorOnLightBackground(this->colorOnLightBackground());