adding buttons to a form

dear user, you can do like:
1. drawing something on content, and then add to page content.
2. add url link annotation(Page.AddAnnotURI) over drawing content(in same area rect), and set a special url header other than "http://"
3. process callback PDFLayoutListener.OnPDFOpenURI(), when the uri string has special prefix string, you can process by native codes.

as feature you mentioned, seems can't handle by PDF button. java script of PDF can't do some systemic features.