Bug 211773 Legend entries overlap
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/LegendBuilder.java
new Point( dExtraWidth, dHeight - dDeltaHeight ),
						dFWidth,
						dFHeight,
						la.getCaption( ).getValue( ),
						dsiBase.size( ) ) );
			}
		}
		
		dColumnWidth = dWidth + legendData.dHorizonalReservedSpace;
		if ( dExtraWidth + dColumnWidth > legendData.dAvailableWidth
				+ legendData.dSafeSpacing )
		{
			dWidth = -legendData.dHorizonalReservedSpace;
		}
		else
		{
			legendData.legendItems.addAll( columnList );
		}
		columnList.clear( );
		dWidth += legendData.dHorizonalReservedSpace + dExtraWidth;
		dHeight = Math.max( dRealHeight, dHeight );
		return new double[]{
				dWidth, dHeight
		};
	}
	/**
	 * Returns a non empty value, if it is null or empty string, replace with specified value.
	 * 
	 * @param value specified value.
	 * @param defaultValue default return value.