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/CurveRenderer.java
*/
	public CurveRenderer( ChartWithAxes _cwa, BaseRenderer _render,
			LineAttributes _lia, Location[] _lo, double _zeroLocation,
			boolean _bShowAsTape, double _tapeWidth, boolean _bFillArea,
			boolean _bTranslucent, boolean _bUseLastState, boolean _bDeferred,
			boolean _bKeepState, Fill paletteEntry,
			boolean usePaletteLineColor, boolean connectMissingValue )
	{
		cwa = _cwa;
		bRendering3D = _lo instanceof Location3D[];
		loPoints = _lo;
		tempPoints = _lo;
		bConnectMissingValue = connectMissingValue;
		bFillArea = _bFillArea;
		bShowAsTape = _bShowAsTape;
		bDeferred = _bDeferred;
		loa = ( bShowAsTape || bFillArea ) ? new Location[4] : null;
		loa3d = ( bRendering3D ) ? new Location3D[4] : null;
		if ( _tapeWidth == -1 )
		{
			dTapeWidth = _cwa.getSeriesThickness( ) * _render.getDeviceScale( );
		}
		else
		{
			dTapeWidth = _tapeWidth;
		}
		if ( loa != null )
		{
			for ( int i = 0; i < 4; i++ )
			{