Maybe the most disturbing thing about Docear is the lack of a proper PDF reader that creates comments, bookmarks and highlighted text that can be imported by Docear and that runs on all operating systems. Personally, I use Foxit Reader and create bookmarks to remember important statements but it can’t highlight text properly. PDF XChange Viewer could be a great alternative if they had persistent object numbers – but they don’t (read here for more details).
Due to the lack of a truly proper Java PDF viewer, we are considering to develop our own PDF viewer. There are plenty of Java PDF libraries out there. However, I had a look at them and none of seem is really suitable. Aspose PDF, iText, jPod Renderer>, PDF Tron, Big Faceless Java PDF, CABAReT Stage, jPDFBookmarks, JPedal, PDFBox, ICE Pdf, ReMarksPDF, and Qoppa’s jPDFViewer all have some shortcomings. Either they have many features but are commercial (e.g. Big Faceless Java PDF), or they are open source but do not offer the required feature or have serious bugs (e.g. PDFBox).
So, my question: Do you know of any other Java PDF libraries or even better a fully functional Java PDF viewer? Our requirements are:
- The PDF Viewer must be written in Java and cross-platform
- The PDF viewer must be able to create bookmarks, comments and highlighted text in Adobe’s standard PDF format
- The text of the highlighted text must be copied into a “pop-up box” as PDF XChange is doing it
- It must be possible to open a PDF on a specific location, ideally on the location of a bookmark/comment/highlighted text, but at least on a specific page.
- ObjectIDs of annotations (bookmarks, comments, highlighted text) must be persistent. For instance, PDF XChange Viewer has no persistent ObjectIDs – it changes objectIDs of bookmarks each time the user makes changes on the PDF and saves it and that is not desired for Docear’s PDF Viewer.
And one more question: If we had found the perfect Java PDF library, but it would be commercial, would you be willing to pay for a PDF viewer? If yes, how much?
Please also let us know if you know someone who would be able to implement a PDF viewer with full-annotation support. We might have some funds available to pay him.