How can i install Pisa on Ubuntu?
http://xhtml2pdf.appspot.com/static/pisa-en.html
What is the best way to install it ?
pisa is an abandoned project. The very first line of its entry says:
PLEASE SWITCH TO THE MORE RECENT VERSION AT: http://pypi.python.org/pypi/xhtml2pdf
If you really want to use the obsolete pisa, you can. You linked to the install docs, which show you exactly what to do.
Unlike pisa, xhtml2pdf is designed to install using pip, and the requirements are set up properly (in particular, using Pillow, which can be pulled in automatically, instead of PIL, which often doesn't work), so all you have to do is:
pip install xhtml2pdf
This will automatically pull in all of html5lib, pyPdf2, Pillow, reportlab, and six if you don't already have them, then install xhtml2pdf, and then you're done.
If you don't already have pip, install it first.
On *nix, if you're not using a virtualenv, user site-packages, or group-writable site-packages, you will of course need sudo pip install xhtml2pdf instead. (But you really should consider using a virtualenv instead.)