What annotation types are supported by XFDF?

Q:

I’m new to the XFDF file format. What kinds of annotations does it support?

A:

he XFDF Specification (http://adobe.ly/1q4psOj) enumerates which annotation types are supported by XFDF:

Supported Annotations
Text
FreeText
Line
Square
Circle
Polygon
Polyline
Highlight

Unsupported Annotations
Movie
Widget
Screen
PrinterMark
TrapNet

However, you can still use PDFNet to extract “unsupported” annotations, as the following KB article describes:

https://groups.google.com/d/msg/pdfnet-sdk/0-9tjRVpG9U/zwnnl0QL8wEJ