I occasionally receive PDFs on which I want to mark comments, or some points/segments of which I want to annotate somehow - similarly to what I would do with printed PDFs.
This does not mean editing the contents - which stays just as it is - only addition of (clearly differentiable) comments - "red pen" style - on the page.
So - I want a piece of software which does this.
- Works on Linux
- GUI of course
- Does not mess up the layout of the PDF (i.e. additions-only)
- Reasonable responsiveness on "heavy" and long PDF documents
Note I haven't listed a license requirements
- Libre license
- Can save the PDF-cum-comments as another PDF file, which will display properly, with the comments, in a typical PDF reader
- Actively maintained
- Offers extra functionality when noticing the PDF was created a certain way, e.g. with LaTeX, or LibreOffice, or Microsoft Office etc.
- Supports both comments and annotations
- Supports multiple comment authors (e.g. with different color comments)
- Doesn't make it easy to edit the PDF when I don't want to edit it.
- Allows extracting/saving the comments/annotations as plain text or some other format convertible to plain text.