Bug 214197 [Regression] Auto scale does not work correctly [13]
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/withaxes/AutoScale.java
if ( caMax == null )
				{
					caMax = cValue;
				}
				if ( cValue.before( caMin ) )
					caMin = cValue;
				else if ( cValue.after( caMax ) )
					caMax = cValue;
			}
			oMinValue = new CDateTime( caMin );
			oMaxValue = new CDateTime( caMax );
			if ( axisOrigin != null
					&& axisOrigin.getType( )
							.equals( IntersectionType.VALUE_LITERAL )
					&& axisOrigin.getValue( ) instanceof DateTimeDataElement )
			{
				CDateTime origin = asDateTime( axisOrigin.getValue( ) );
				if ( oMinimum == null && origin.before( oMinValue ) )
				{
					oMinimum = axisOrigin.getValue( );
				}
				if ( oMaximum == null && origin.after( oMaxValue ) )
				{
					oMaximum = axisOrigin.getValue( );
				}
			}
			int iUnit;
			if ( oStep != null || oStepNumber != null )
			{
				iUnit = ChartUtil.convertUnitTypeToCalendarConstant( scModel.getUnit( ) );