We all know that we can highlight certain texts in a pdf file either using Adobe Acrobat or Preview on Mac. I’m wondering how I can extract all these highlights in a pdf file, and generate a summary (a note kind of thing).
The following post
PDF: standard format for highlights?
points out that there are multiple ways to do highlighting. Will it be a challenge to distinguish the original content of the file and the user-added highlights if shapes with transparency is used to achieve highlights?
Details about this can be found in open source pdf parsing-rendering libraries, and you just have to read the code or document if available.