Converts exported PDF annotations from FDF to XFDF. Support for forms data is marginal.
Directly working with FDF is not fun. It's much easier with XFDF and existing XML support in your tool of choice. However, XFDF doesn't seem to receive much love from PDF software such as Foxit Reader, hence the need for a converter.
In the current state, this tool supports just what I need to scratch my own itch. It is not very robust and supports only a subset of the existing annotation types and properties. If you need more, feel free to contribute or to contact us.
This PostScript program can be run on the command line with Ghostscript.
gsnd -q fdf2xfdf.ps annots.fdf > annots.xfdf
gswin64c -dNODISPLAY -q fdf2xfdf.ps annots.fdf > annots.xfdf
(Or gswin32c for the 32 bit version.) This requires that the GhostScript executables are on the PATH environment variable. Alternatively, specifiy the full path to gswin32c.exe, e.g.
"C:\Program Files\gs\gs9.21\bin\gswin64c.exe" -dNODISPLAY -q fdf2xfdf.ps annots.fdf > annots.xfdf
fdf2xfdf is at the moment not directed towards forms data, though marginal support is present. See various other tools for alternatives, e.g.:
As PostScript is sort of the older brother of PDF, it shares a lot of DNA with PDF - such as syntax, types and data structures. FDF parsing virtually comes for free with PostScript.