title: Changing the text and background color of a PDF file
body: <p>I'd like to change the background color and text color programmatically in PDF documents so that they're nicer to read at night (kinda like in Adobe Reader: <em>Edit -> Preferences -> Accessibility -> Replace Document Colors</em>). </p>
  
  <p>Is there any good command line tool or API for Windows that can do that? </p>
  
  <p>So far I haven't found any. It's OK if it needs to save the newly colored PDF into a new file.</p>