fix converting double to date time and vice versa

src/backend/core/datatypes/DateTime2DoubleFilter.h

@@ -40,10 +40,11 @@ class DateTime2DoubleFilter : public AbstractSimpleFilter {
 public:
 	virtual double valueAt(int row) const {
 		if (!m_inputs.value(0)) return NAN;
-		QDateTime input_value = m_inputs.value(0)->dateTimeAt(row);
-		if (!input_value.isValid()) return NAN;
-		return double(input_value.date().toJulianDay()) +
-			double( -input_value.time().msecsTo(QTime(12,0,0,0)) ) / 86400000.0;
+		QDateTime inputDate = m_inputs.value(0)->dateTimeAt(row);
+		if (!inputDate.isValid()) return NAN;
+		QDateTime start(QDate(1900, 1, 1));
+		return double(start.daysTo(inputDate)) +
+			double( -inputDate.time().msecsTo(QTime(0,0,0,0)) ) / 86400000.0;
 	}
 
 	//! Return the data type of the column
@@ -51,7 +52,7 @@ public:
 
 protected:
 	//! Using typed ports: only DateTime inputs are accepted.
-	virtual bool inputAcceptable(int, const AbstractColumn *source) {
+	virtual bool inputAcceptable(int, const AbstractColumn* source) {
 		return source->columnMode() == AbstractColumn::DateTime;
 	}
 };

src/backend/core/datatypes/Double2DateTimeFilter.h

@@ -43,15 +43,16 @@ public:
 		if (!m_inputs.value(0)) return QDate();
 		double inputValue = m_inputs.value(0)->valueAt(row);
 		if (std::isnan(inputValue)) return QDate();
-		return QDate::fromJulianDay(qRound(inputValue));
+		//QDEBUG("	convert " << inputValue << " to " << QDate(1900, 1, int(inputValue)));
+		return QDate(1900, 1, 1 + int(inputValue));
 	}
 	virtual QTime timeAt(int row) const {
 		if (!m_inputs.value(0)) return QTime();
 		double inputValue = m_inputs.value(0)->valueAt(row);
 		if (std::isnan(inputValue)) return QTime();
-		// we only want the digits behind the dot and
-		// convert them from fraction of day to milliseconds
-		return QTime(12,0,0,0).addMSecs(int( (inputValue - int(inputValue)) * 86400000.0 ));
+		// we only want the digits behind the dot and convert them from fraction of day to milliseconds
+		//QDEBUG("	convert " << inputValue << " to " << QTime(0,0,0,0).addMSecs(int( (inputValue - int(inputValue)) * 86400000.0 )));
+		return QTime(0,0,0,0).addMSecs(int( (inputValue - int(inputValue)) * 86400000.0 ));
 	}
 	virtual QDateTime dateTimeAt(int row) const {
 		return QDateTime(dateAt(row), timeAt(row));