Pdf

Encoding/Manipulation

ghostscript		CLI utility for ps/pdf manipulation
pypdf		python module for pdf authoring/manipulation

File Format

PDFs are composed of boxes, ....

Boxes

mediabox		The largest dimension - contains all crop-marks etc for printing.
cropbox		Where the page should be clipped (in pdf viewer/when printed)
bleedbox		Where the printed material should be clipped (generally slightly larger than cropbox for print)
trimbox		The actual width/height
artbox		seldom used, allows you to crop small componenents from a pdf for printing.