Base: add convenience functions to create a QString from quantity or double

src/Base/Quantity.cpp

@@ -63,6 +63,14 @@ QuantityFormat::QuantityFormat()
 {
 }
 
+QuantityFormat::QuantityFormat(QuantityFormat::NumberFormat format, int decimals)
+  : option(OmitGroupSeparator | RejectGroupSeparator)
+  , format(format)
+  , precision(decimals < 0 ? UnitsApi::getDecimals() : decimals)
+  , denominator(defaultDenominator)
+{
+}
+
 // ----------------------------------------------------------------------------
 
 Quantity::Quantity()

src/Base/Quantity.h

@@ -75,6 +75,7 @@ struct BaseExport QuantityFormat {
         denominator = denom;
     }
     QuantityFormat();
+    QuantityFormat(NumberFormat format, int decimals=-1);
     inline char toFormat() const {
         switch (format) {
         case Fixed:

src/Base/UnitsApi.cpp

@@ -154,6 +154,17 @@ void UnitsApi::setSchema(UnitSystem s)
     UserPrefSystem->setSchemaUnits(); // if necessary a unit schema can change the constants in Quantity (e.g. mi=1.8km rather then 1.6km).
 }
 
+QString UnitsApi::toNumber(const Base::Quantity& q, const QuantityFormat& f)
+{
+    QString number = QString::fromLatin1("%1").arg(q.getValue(), 0, f.toFormat(), f.precision);
+    return number;
+}
+
+QString UnitsApi::toNumber(double d, const QuantityFormat& f)
+{
+    QString number = QString::fromLatin1("%1").arg(d, 0, f.toFormat(), f.precision);
+    return number;
+}
 
 //double UnitsApi::translateUnit(const char* str)
 //{

src/Base/UnitsApi.h

@@ -66,6 +66,13 @@ public:
         return UnitsApi::schemaTranslate(quant, dummy1, dummy2);
     }
 
+    /** Get a number as string for a quantity of a given format.
+     * The string is a number in C locale (i.e. the decimal separator is always a dot) and if
+     * needed represented in scientific notation. The string doesn't include the unit of the quantity.
+     */
+    static QString toNumber(const Base::Quantity& q, const QuantityFormat& f = QuantityFormat(QuantityFormat::Default));
+    static QString toNumber(double d, const QuantityFormat& f = QuantityFormat(QuantityFormat::Default));
+
     /// generate a value for a quantity with default user preferred system
     static double toDbl(PyObject *ArgObj,const Base::Unit &u=Base::Unit());
     /// generate a value for a quantity with default user preferred system