I have always used diffpdf. Its been around forever. I don't know if it is what is used in the screenshot: http://www.qtrac.eu/diffpdf-foss.html http://www.qtra

I have always used diffpdf. Its been around forever. I don't know if it is what is used in the screenshot: http://www.qtrac.eu/diffpdf-foss.html http://www.qtrac.eu/diffpdf-foss.html