Gets or sets the interior colour (IC, PDF 1.4) a square, circle, polygon or line ending is filled with; null, the default, fills nothing.
public PdfDeviceColor? InteriorColor { get; set; }
ISO 32000-2 §12.5.6.8, Table 180; §12.5.6.9, Table 181; §12.5.6.7, Table 178.