
According to the PDF specification, a soft mask can be specified as a PDF name object or as a dictionary, see GrapeCity.Documents.Pdf.Graphics.SoftMaskNamed and SoftMask.
'Declaration Public MustInherit Class SoftMaskBase
public abstract class SoftMaskBase
System.Object
GrapeCity.Documents.Pdf.Graphics.SoftMaskBase
GrapeCity.Documents.Pdf.Graphics.SoftMask