[TD]fix dim text wrong side of dim line (fix #16172)

src/Mod/TechDraw/App/DrawViewDimension.cpp

@@ -768,6 +768,25 @@ double DrawViewDimension::getProjectedDimValue() const
 }
 
 
+pointPair DrawViewDimension::getLinearPoints() const
+{
+    Base::Vector3d stdY{0, 1, 0};
+    if (Type.isValue("Distance")) {
+        // if the dimVec points the wrong way on generally vertical dims, the dim text will be
+        // placed on the wrong side of the dim line.
+        auto dimVec = m_linearPoints.second() - m_linearPoints.first();
+        dimVec.Normalize();
+        auto dotY = stdY.Dot(dimVec);
+        if (dotY > 0) {
+            // dimVec points up (ish) so the dim text will be to right of dim line and readable from
+            // left side of the page.  Dimensions should always be readable from the bottom-right, so
+            // we flip the points.
+            return {m_linearPoints.second(), m_linearPoints.first()};
+        }
+    }
+    return m_linearPoints;
+}
+
 pointPair DrawViewDimension::getPointsOneEdge(ReferenceVector references)
 {
     // Base::Console().Message("DVD::getPointsOneEdge()\n");

src/Mod/TechDraw/App/DrawViewDimension.h

@@ -158,10 +158,8 @@ public:
     bool hasBroken3dReferences() const;
 
 
-    virtual pointPair getLinearPoints() const
-    {
-        return m_linearPoints;
-    }
+    virtual pointPair getLinearPoints() const;
+
     virtual void setLinearPoints(Base::Vector3d point0, Base::Vector3d point1)
     {
         m_linearPoints.first(point0);