Bug 176582 "Show Lines as Curves" does not work correctly for Area Chart [0001]
Description: "Show Lines as Curves" does not work correctly for Area Chart. Build number: 2.2.0.v20070307-1128 Steps to reproduce: 1. New a Area Chart. 2. In "Format Chart" tab, select Series->Value (Y) Series, tick and untick "Show Lines as Curves" checkbox. Expected result: Null value point e is treated the same when tick and untick "Show Lines as Curves" checkbox. Actual result: Null value point e is treated differently (see the screenshot). Error log: N/A
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/render/BaseRenderer.java
if ( iProperty == IConstants.MIN )
		{
			dY = loa[0].getY( );
			for ( int i = 1; i < iCount; i++ )
			{
				dY = Math.min( dY, loa[i].getY( ) );
			}
		}
		else if ( iProperty == IConstants.MAX )
		{
			dY = loa[0].getY( );
			for ( int i = 1; i < iCount; i++ )
			{
				dY = Math.max( dY, loa[i].getY( ) );
			}
		}
		else if ( iProperty == IConstants.AVERAGE )
		{
			for ( int i = 0; i < iCount; i++ )
			{
				dY += loa[i].getY( );
			}
			dY /= iCount;
		}
		return dY;
	}
	/**
	 * Finds particular X value from given location list.
	 * 
	 * @param loa