Implement undo and redo feature for annotations

I don't have Matrix object as I get the annotation as:
m_annot = page.GetAnnotFromPoint(m_annot_pos.x, m_annot_pos.y);

I have to extract Matrix object from m_annot.
How can I get it?

Hello nermeen,
Please help me to solve this problem.

You can use Annotation.GetMarkupRects() to construct the matrix,
Or if you intercept the annotation creation, you can save index1 and index2 and use www.androidpdf.mobi/documentation/javado....html#AddAnnotMarkup (int, int, int) instead

The link you have provided is dead, please resend the link.

it's a reference to the javadoc
www.androidpdf.mobi/documentation/javadocs/
www.androidpdf.mobi/documentation/javado....html#AddAnnotMarkup (int, int, int)

please provide a code snippet to do so, I am unable to get any result out of it.