Color of the bevel effect. This property is supported in 2D mode only. The default value is nil (that means no bevel).
Use this property to add a bevel effect to the series. You can achieve different effects with different colors. For example, to add a shadow inside the pie circle, set the color like [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.25f]. You also have to set bevelRatio for NChartPieSeriesSettings to get the bevel effect.