I want to add ruler on top and left side my wpf page, where scale changes dynamically on zoom in and zoom out same as in Ms word. I am using pdftron to view pdf document. please help me.
Please see this forum post, which should help you get started doing your own custom control.
https://groups.google.com/d/msg/pdfnet-sdk/oJ2nxQpvG14/Ex0uVPGCCwAJ