shared annotation for pdf
basic idea is to have a shared-annotation pdf document for something like a journal club
functionality
- you can scribble on pdf, and whatever you write is shared
- you can clear all scribbles on the pdf
- you can propagate your focus (transform matrix) to all others so they can see what you're seeing
desired functionality
- keep pdf format or reduce size of image, cause I'm currently converting pdf to an image so it's usable in html canvas
- make it tablet compatible