[pdf export] low quality of new export method compared to the legacy

Hi,

Thanks for wonderful project! I just found it, better later than never.

I just had a case in which I got a document to sign, but when export to pdf quality significantly dropped.

I used the legacy method and quality was preserved, however the text additions were reported to be garbage.

Attached are:
000 - original.pdf - the original pdf
000 - original.pdf.xoj - the xournal version with minor text addition
001 - new method.pdf - export to pdf using new method
002 - legacy method.pdf - export to pdf using the legacy method

Notice the change in quality between the legacy and the new, this is a scanned document, a picture, there are no option to tune the output, unsure what exactly happening.

Also please notice that the garbage of text additions within the legacy format is not visible always, however, you can see this behaviour online using[1], upload the legacy and the new and observe the text within the box.

So I had an issue of lose lose... either use the new format with lower quality or the legacy format with garbage.

Thanks!

[1] http://pdfviewer.softgateon.net/