RDF: Abiword and Calligra

Over the last few years I've been fortunate enough to hack on Calligra and Abiword, adding support for the RDF/XML that can be stored as part of an ODF document. Both suites can also interact with each other, allowing RDF to move over the clipboard along with the text content.

There are some things abiword can do with RDF that Calligra currently can't. These include highlighting the parts of the document that have RDF associated and initial support for capturing relations between things in RDF. Such relationships from RDF can give back to the user right off the bat. For example they can be useful for navigating the document by semantics, moving from a child to their parent, or the cat to it's owner. RDF also opens up document computing to other possibilities like navigating by time rather than by the linear sequence of pages.

I am currently looking to do some more development around ODF. It would be wonderful to do some more indepth hacking on either project as they both have a very nice, welcoming, open source team behind them. If anybody knows of some sponsored hacking floating around for these tools, please get in touch :)

I recently committed a small change to Calligra to move back to using intrusive reference counting for some non graphical RDF objects. While Calligra can use marble to allow editing locations from RDF, I used marble at a level in the calligra stack that isn't optimal, so have to shift that to a plugin to allow it to be easily accessible to distribution builds.

Copy and Paste with Semantics...

Copy and Paste now preserves RDF between both Calligra and abiword in both directions. This lets you select some text in a document in either application, copy it, and paste it into the other application and have the RDF that is associated with that part of the document go along with the text you selected.

In the below screencast, the document that Calligra is editing has some contact and event information stored in RDF. The three people in the first sentence all have contact information associated. As you can see, the RDF sidepanel in Calligra lets you know about this as the cursor moves around. James has his phone number captured in RDF which the edit dialog shows. If I select one or more of these contacts and "Copy" them to the clipboard, Calligra creates an ODF file with embedded RDF in it and offers that on the clipboard.

Abiword is happy to accept that ODF content and when you paste it into a document you can see that the RDF links are preserved, and that there are 7 RDF triples associated with James. Of course, you want full disclosure of this information, so clicking show RDF lets you examine and edit those RDF triples.

Copy and Paste of RDF from Calligra to Abiword from Ben Martin on Vimeo.

I put a little trick in going the other way just to spice things up a little bit. The multi.odt file that I have open in abiword has two RDF links in scope at the Wing-B link. RDF is associated with the whole paragraph and explicitly with the link itself. In particular, the uri:widetime is associated with the paragraph while the uri:wingb is associated with the RDF link itself. Once I grab that RDF link and copy it to the clipboard, again an ODF file is offered (as well as text and rtf), and again Calligra is more than happy to accept an ODF file on the clipboard. Notice that when I show all the RDF in Calligra both the widetime and wingb RDF triples have now become part of the document.

Copy and Paste from Abiword to Calligra from Ben Martin on Vimeo.

I made some changes in both calligra and abiword to get this to happen. Changes to the former were quite small. You'll have to grab trunk from both applications if you want to play along at home. The code is committed in both trees.

Calligra & RDF Smaak

As some readers will already know, the ODF document standard has support for including one or more RDF/XML files. I have made a few such files, and will grow that collection over time. The weekend hike document cites a few people, links some to a location and also cites a time and place. While one could just say "Dom Plein" or "11 am Wednesday" these purely text references are subjective and require a human to read them.

On the other hand, the location could have an exact bounding polygon or point with digital longitude and latitude information. A computer is all to happy to use that precise description to offer maps and "how to get there from here" type information. And the 11am is of course dubious because it doesn't link to a timezone, a human will know we are not talking UK time or the ACDT timezone. But that requires inference from the cited location and knowledge of which Plein that is, or rather, which timezone that Plein is in.

I did a little hacking to freshen up some of the RDF code in Calligra and bring back optional support for using Marble to show and edit location information. The below is the weekend hike example from the github above. James, Joyce, and Mark all have contact RDF associated, with Mark also giving his location. The "next weekend" at the end of the first paragraph has both a time and place associated. In the screenshot I've opened up the place to edit it. Rather simple to drag a map around and click OK than to know the digital coordinates right of the top of your head ;)


I was hacking on fixing the same bug as boemann on #calligra, which is strange for me as I normally don't overlap on things. It seems along the way setCanvas() was called again so I removed my explicit view passing stuff in the update I just git pushed. It looks like the docker was fixed correctly by somebody else in the end. My SPARQL updates should still help. It has been a while since I hacked on this codebase, and I have to thank the Calligra guys for being so welcoming and having such a fun contribution environment! I'm fortunate to be able to hack on two projects, Abiword and Calligra, which are both so welcoming :)

ODF and Generic Change Tracking: part II, styles.

So now abiword can save and load ODF files with improved generic tracked changes to styles. These style changes might be nested, and the window that a style is applied to might shift over revisions. The below video demonstrates the scenario in example 6.4.2 of the generic track changes proposal that is being considered by the Advanced Document Collaboration OASIS ODF Technical subcommittee.

The actual serialization to ODF is along the lines of my proposed output but also using the ac:change stack to avoid unnecessary nesting as has been mentioned that OpenOffice might produce and consume if the generic proposal were to be chosen by the oasis subcommittee.

ODT Change Tracking part 2: Example 6.4.2 from Ben Martin on Vimeo.

ODF and Generic Change Tracking

The OASIS group who are responsible for things like the Open Document Format (ODF) format are throwing around how to improve how change tracking information is to be contained in future versions of ODF. I've hacked some support for the "generic" change tracking proposal into Abiword in a git branch, and Ganesh Paramasivam has been working to make Calligra and KOffice support this too.

I thought a little bit of a look at how documents move between suites was in order. Obviously, these are really trivial changes. The larger use cases screem out for an automated system to test them, so that regressions can be caught and other office suites added over time if they choose to support this method of change tracking.

So, without further (or less) ado, the below video shows a document created in KOffice and bounced through a temporary file to abiword and inspected. Apologies for the delays in the first video, I've sorted that issue of frame dups out for future shows.

2011 April 9: KOffice and Abiword with Generic Change Tracking 1of2 from Ben Martin on Vimeo.

In the second video I make some changes in abiword and send those back to KOffice. In the process I found a few little issues which I've committed some updates to the abiword git repo to help with.

2011 April 9: KOffice and Abiword with Generic Change Tracking 2of2 from Ben Martin on Vimeo.

These videos where created with recordmydesktop, transcoded with mencode for 720 playback (mainly getting the video codec how vimeo wants to see it), and uploaded with ferriscp foo.avi vimeo://upload.