add Scale::coordName()

Base/Axis/Scale.cpp

@@ -64,6 +64,11 @@ std::string Scale::axisLabel() const
     return m_coord->label();
 }
 
+std::string Scale::coordName() const
+{
+    return Coordinate(axisLabel()).name();
+}
+
 std::string Scale::unit() const
 {
     return Coordinate(axisLabel()).unit();

Base/Axis/Scale.h

@@ -80,6 +80,7 @@ public:
 
     friend std::ostream& operator<<(std::ostream& ostr, const Scale& ax);
 
+    std::string coordName() const;
     std::string unit() const;
 
     Scale plottableScale() const;