title: Cropping pages of a .pdf file
body: <p>I was wondering if anyone had any experience in working programmatically with .pdf files. I have a .pdf file and I need to crop every page down to a certain size.</p>
  
  <p>After a quick Google search I found the pyPdf library for python but my experiments with it failed. When I changed the cropBox and trimBox attributes on a page object the results were not what I had expected and appeared to be quite random.</p>
  
  <p>Has anyone had any experience with this? Code examples would be well appreciated, preferably in python.</p>