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
{
		return cm;
	}
	/**
	 * @return Returns computation object associated with current renderer.
	 */
	public final Object getComputations( )
	{
		return oComputations;
	}
	/**
	 * @return Returns device renderer associated with current renderer.
	 */
	public final IDeviceRenderer getDevice( )
	{
		return ir;
	}
	/**
	 * Renders a 2D or extruded 2D plane as necessary for a given front surface
	 * polygon. Takes into account the correct z-ordering of each plane and
	 * applies basic lighting. This convenience method may be used by series
	 * type rendering extensions if needed.
	 * 
	 * @param ipr
	 *            A handle to the primitive rendering device
	 * @param oSource
	 *            The object wrapped in the polygon rendering event
	 * @param loaFront
	 *            The co-ordinates of the front face polygon
	 * @param f