Add partial specialization for float and double

In PdmFieldWriter::writeFieldData, the numeric values are converted to string with a selected precision. isEqual() is used when comparing values for field editors in PdmFieldUiCap<FieldType>::valueOptions()

Fwk/AppFwk/cafProjectDataModel/cafPdmCore/cafInternalPdmValueFieldSpecializations.h

@@ -195,4 +195,46 @@ public:
     }
 };
 
+//==================================================================================================
+/// Partial specialization for float
+//==================================================================================================
+template <>
+class PdmValueFieldSpecialization<float>
+{
+public:
+    static QVariant convert( const float& value ) { return QVariant::fromValue( value ); }
+
+    static void setFromVariant( const QVariant& variantValue, float& value ) { value = variantValue.value<float>(); }
+
+    static bool isEqual( const QVariant& variantValue, const QVariant& variantValue2 )
+    {
+        // See PdmFieldWriter::writeFieldData for the precision used when writing float values
+        // This function is used when comparing values for field editors in PdmFieldUiCap<FieldType>::valueOptions()
+
+        const float epsilon = 1e-6f;
+        return qAbs( variantValue.value<float>() - variantValue2.value<float>() ) < epsilon;
+    }
+};
+
+//==================================================================================================
+/// Partial specialization for double
+//==================================================================================================
+template <>
+class PdmValueFieldSpecialization<double>
+{
+public:
+    static QVariant convert( const double& value ) { return QVariant::fromValue( value ); }
+
+    static void setFromVariant( const QVariant& variantValue, double& value ) { value = variantValue.value<double>(); }
+
+    static bool isEqual( const QVariant& variantValue, const QVariant& variantValue2 )
+    {
+        // See PdmFieldWriter::writeFieldData for the precision used when writing double values
+        // This function is used when comparing values for field editors in PdmFieldUiCap<FieldType>::valueOptions()
+
+        const double epsilon = 1e-8;
+        return qAbs( variantValue.value<double>() - variantValue2.value<double>() ) < epsilon;
+    }
+};
+
 } // End of namespace caf

Fwk/AppFwk/cafProjectDataModel/cafPdmXml/cafPdmXml_UnitTests/cafPdmXmlNumberTest.cpp

@@ -110,3 +110,39 @@ TEST( SerializeNumbers, SimpleObjectWithFloatValues )
         EXPECT_TRUE( diffB < epsilon );
     }
 }
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+TEST( SerializeNumbers, TestPresicion )
+{
+    double valueB = 0.1234567890123456789;
+
+    QString objectAsText;
+
+    {
+        SimpleObjectWithNumbers obj1;
+
+        obj1.m_valueB = valueB;
+
+        objectAsText = obj1.writeObjectToXmlString();
+    }
+
+    SimpleObjectWithNumbers obj1;
+    obj1.readObjectFromXmlString( objectAsText, caf::PdmDefaultObjectFactory::instance() );
+
+    // Test the precision of the value serialized to text
+    // See PdmFieldWriter::writeFieldData for the precision used when writing float values
+
+    {
+        const double epsilon = 1e-15;
+        auto         diff    = fabs( obj1.m_valueB - valueB );
+        EXPECT_FALSE( diff > epsilon );
+    }
+
+    {
+        const double epsilon = 1e-16;
+        auto         diff    = fabs( obj1.m_valueB - valueB );
+        EXPECT_TRUE( diff > epsilon );
+    }
+}