Try this script
calendars.7z (Size: 11.91 KB / Downloads: 37)
Once they are in the scripts directory, refresh the script via Filters > Script-Fu > Refresh Scripts or just restart GIMP.
Then you will find them in Filters > Render > Calendar > Month / Year
Explanation and example are over-there > http://gimpchat.com/viewtopic.php?f=9&t=20565&start=0
It's not as "evolved" than your example, but might do the trick, it's a SCM thus works on any OS
calendars.7z (Size: 11.91 KB / Downloads: 37)
Once they are in the scripts directory, refresh the script via Filters > Script-Fu > Refresh Scripts or just restart GIMP.
Then you will find them in Filters > Render > Calendar > Month / Year
Explanation and example are over-there > http://gimpchat.com/viewtopic.php?f=9&t=20565&start=0
It's not as "evolved" than your example, but might do the trick, it's a SCM thus works on any OS
Patrice