Support for document annotations

[florian-wagner]

exportNotebook works great for handwritten notes, but not for annotations made within a document pdf. In such cases one currently get's a blank PDF with annotations only, i.e. without the underlying document. This PR changes this by:

• checking if ${id$}.pdf exists and using it as background.pdf instead of performing template conversion
• ensuring that transparency is preserved by using the pdftk argument multistamp instead of multipage
• Stripping redundant .pdf suffix if it already exists in $filename
• Optionally allowing for colored annotations by an additional rMsvg argument --coloured_annotations or simply -c
• Passing these (and any other additional) arguments from exportNotebook to rMsvg
• (Fixing some PEP8 in rMsvg)

Examples

Small help message if no argument is provided

$ ~ exportNotebook           
Usage: ./exportNotebook (Partial)NotebookName AdditionalrM2svgArguments
You can additionally append the -c argument for coloured annotations.

Normal behavior

Calling exportNotebook remarkable works as expected, i.e. uses the underlying pdf as the background and not a succesion of Blank templates: remarkable.pdf

Custom behavior

Calling exportNotebook remarkable -c creates the following: remarkable-c.pdf

Current limitations

If the PDF was cropped, the annotations are shifted. I haven't figured out where the crop information is stored and how the foreground.pdf can be transformed accordingly. Anyone has an idea?

Please consider merging. It think this could be of value for a lot of users who use the remarkable to annotate academic PDFs.

[edupont]

Thanks a lot !