Source code annotation tool [closed]

Question

I'm looking for a tool with which I can annotate source code.

I have some 3rd party source code (JavaScript) I need to understand and I don't want to change it (add inline comments) so that

• line numbers can stay intact (for communication with others),
• I can avoid accidentally changing something and
• my annotations stand out compared to the authors comments.

Normally I would print the whole thing out an scribble on it, but the code is too long for that and I need to share it per email. I would be great if one could do some like that including being able to create "links" between so places in the code, possibly even visually with a lines or arrows.

Answer 1

If you would usually print it (if it were shorter), why not print it to a PDF and then use a PDF viewer that supports comments, like Foxit Reader? :)