I was long in search of a tool which can annotate PDF and save my comments. I did a lot of search in the opensource forums and never really got exactly what I wanted. Recently, Prof. Kumar introduced me to this excellent tool called xournal, an application for notetaking, sketching, keeping a journal using a stylus . This tool is developed and maintained by Prof. Denis Auroux of MIT. This simple and elegant tool fulfills all the demands that a student reading a paper can ask for. This is particularly useful when working in a group which is geographically dispersed and everybody wants to share their thoughts by writing their comments on a common paper or writeup. It also saves paper, which is very very appealing to people who care for a green Earth. The tool is very simple and easy to install. The official page is here. One can download and install from source code. If you use Ubuntu, this is even simpler, just open the terminal and type:
sudo apt-get install xournal
and voila ! It is free software under GPL and runs on Linux (recent distributions) and other GTK+/Gnome platforms. It also has versions for Win32. Its graphical quality and the features are amazing. Once you are done with your markups on a PDF file, you can export it again as PDF and save the file with your markups. A screenshot of the working xournal window is here:
Just enjoy using the tool and spread the word, since that’s the way opensource survives.