title: How can I edit PDF files in an iOS application?
body: <p>In my iPhone / iPad application, I show a person's medical reports in the form of a PDF. I have saved the reports in the documents directory and am reading them from there.</p>
  
  <p>I want the user to be able to add or edit comments on these PDFs, as well as be able to highlight certain sections in the PDF. After editing, the application should be able to save the PDF back into the documents directory.</p>
  
  <p>Is this possible within an iOS application?  If so, how?  Is this a task for Core Graphics?</p>