This class represents the ink annotation. This is definitively detailed in:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 182, page 405.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 185, page 491.

This class is always an indirect object because it inherits from MarkupAnnotationElement which is always an indirect object.

System.Object
    WebSupergoo.ABCpdf14.Elements.Element
       WebSupergoo.ABCpdf14.Elements.AnnotationElement
          WebSupergoo.ABCpdf14.Elements.MarkupAnnotationElement
             WebSupergoo.ABCpdf14.Elements.InkAnnotationElement

An ink annotation records one or more freehand strokes, each a list of points rendered as a connected smooth curve. The InkList entry holds the array of strokes.

The Path entry (PDF 2.0) provides a compact alternate path representation supporting curved segments.