Hi! I've been using Xournal for note-taking for a while now and I have a few suggestions and feature requests Firstly, I love that it automatically fills in the name field with the date and time (saves time when quickly saving and opening a new note), but it would be nice if it remembered the last successfully saved-to folder, so you don't always have to traverse the file system when saving or exporting a lot of notes. That brings me to the export option. I really like that you can export PDF files easily as it makes notes portable and reusable in other apps. In that note, I'd love some more export options, like: export to PNG and possibly other image formats (with customizable resolution/size, with extra whitespace around sketches or without (cropped to content))
export without the horizontal lines (which are helpful while writing, but not so much when exported, especially with drawings/sketches/diagrams/not text)
These options should of course be remembered like the last saved-to folder too
Exporting is a bit of a chore if you have a lot of notes though, due to the above mentioned remember-folder issue. That said, Xournal could have command line options (which it already might have, but I'm not aware of them), which would allow instant export of Xournal save files to other file formats (provided as the argument and/or implied from file extension). Exporting a lot of them wouldn't bother me so much if the last folder exported to was remembered though
A feature that would really help with note-taking / sketching would be the ability to expand the canvas either automagically (which could create an infinite canvas to draw to) or something along the lines of the Sketch application that came with the N900 (buttons to expand the canvas to left/right/top/bottom). I'm not sure what expanding the canvas would do to the export-to-PDF option, possibly scaling the canvas to fit the PDF page? There should be no problems if you added the export-to-PNG option though
Sharing is nice too, but it'd be even nicer if you didn't have to save an arbitrary PDF somewhere (it could probably save a temporary one somewhere, but that might bring some problems?). I guess it could be nice if it had an insta-share function that would capture the current contents of the page and automatically upload to a site like http://imgur.com/ and return the url somehow or open it automatically, which would make notes instantly available for web usage.
I should mention that this is all just based on my experiences using Xournal to take notes during class - writing equations, sketching pictures and drawing diagrams. I've already written too much about all this, so I should just say thanks for the awesome Xournal and keep up the good work!