Graphometric signature

How can I sign a pdf from Android with a graphometric signature (with Wacom tablet for example)?
Can you give me an example of code to do this?
Thanks
Max

if you means a stamp to be create:
1. create Bitmap in RGBA32 format.
2. create Canvas on Bitmap
3. draw anything to Bitmap.
4. Invoke Page.AddAnnotBitmap and then invoke Bitmap.recycle().

Thanks but I'm already using AddAnnotBitmap to insert the image of a signature (only the image).
We need to add also graphometric informations. We need to sign with a graphometric signature like here www.graphosign.com/