Today is my last day in Brussels where I gave a TextBoxes: complex shapes with complex content and a LibreOffice on Android talk at FOSDEM 2015, in the Open document editors devroom. The devroom was well-crowded, with about 100 users in the rows of the audience — proof pictures above and below. ;-)

We also had a Hackfest with about 20 hackers attending, (again) kindly hosted by Betacowork on Monday and Tuesday:

There were a few topics I hacked on:

A full list of achievements is available, if you were at the hackfest and you did not contribute to that section, please write a line about what did you hack on. :-)

Quite some other slides are now available on Planet, don’t miss them. Mines are also uploaded.

As it has been announced last week, an Android port of LibreOffice in the form of a viewer app is now available for download. What’s next? Editing, naturally. First, thanks again to The Document Foundation — and all the donors who made this (ongoing) work possible. In this post I would like to explain what did we do with Tomaž Vajngerl at Collabora so far in that direction.

If you ever touched the Android port of LibreOffice, you probably noticed that sadly developing for Android is much harder compared to Linux (desktop). On Linux, if you just touch a single module, it’s possible to rebuild just that module in a few seconds, and then you can run soffice again with your modifications included. On Android, this is much harder:

and only then can you test your changes. To partly sidestep from this problem, we split the "Android editing" into two:

One problem with this approach was that while Android properly rendered small tiles of 256x256 pixels, gtktiledviewer rendered a single huge tile. This means that in case part of the document changes and we need to re-draw it, we always repainted the whole document in gtktiledviewer, while we only repainted the necessary parts on Android. Guess what, if the area to be repainted is wrong, it’ll be visible on Android but not on gtktiledviewer. So the first task we solved was to let gtktiledviewer also render small tiles. For debugging purposes, small red rectangles are painted at the top left corners of each rectangle, so the size and position of the tiles can be seen easily:

The next step was to somehow start work on real editing — but where to start? We identified two critical building blocks:

To avoid solving two problems at the same time, we first went after the second. One use case that only requires the update of the view is blinking text. Even if no touch or key events are available, a blinking text wants to update the view using a timer, so it’s a good testcase. It’s now possible for LibreOfficeKit clients to register a notification callback, and using that, LibreOffice can notify clients if part of the view has to be redrawn. Here is how it looks using gtktiledviewer:

This demonstrates that the LibreOfficeKit implementation in LibreOffice core and also the gtktiledviewer client code handle correctly tile invalidations. Once that was done, we could also implement a similar client code in the Android app — it looks like this:

That’s it for now — next on our list is adding support for input handling, so it’s possible to type in some text. :-)

TL;DR: Import of annotated text ranges from binary DOC format was a problem for quite some time, now it should be as good as it always was in the ODT/DOCX/RTF filter.

Longer version: the import of annotation marks from binary DOC was never perfect. My initial implementation had a somewhat hidden, but important shortcoming, in the form of a "Don’t support ranges affecting multiple SwTxtNode for now." comment. The underlying problem was that annotation marks have a start and end position, and this is described as an offset into the piece table (so the unit was a character position, CP) in the binary DOC format, while in Writer, we work with document model positions (text node and content indexes, SwPosition), and it isn’t trivial to map between these two.

Tamás somewhat improved this homegrown CP → SwPosition mapping code, but was still far from perfect. Here is an example. This is how this demo document looks like now in LibreOffice Writer:

And this is how it looked like before the end of last year:

Notice how "Start" is commented and it wasn’t before. Which one is correct? Here is the reference:

The reason is that the document has fields and tables, and the homegrown CP → SwPosition mapping did not handle this. A much better approach is to handle the mapping as we do it for bookmarks: even if at the end annotation marks and bookmarks are entires in sw::mark::MarkManager, it’s possible to set the start position as a character attribute during import (since mapping the current CP to the current SwPosition is easy) and when we know both the start and end, delete the character attribute and turn it into a mark manager entry. That’s exactly what I’ve done. The first screenshot is the result of 3 changes:

Hopefully this makes LibreOffice not only avoid crashing on such complex annotated contents, but also puts an end to the long story of "annotation marks from binary DOC" problems.

TL;DR: If you touch the ODF and/or OOXML filters in LibreOffice, please use the --with-export-validation configure option after you ran the setup.sh script.

Markus Mohrhard did an excellent job with adding the --with-export-validation build switch to LibreOffice. It does the following:

One remaining problem was that it required setting up both odfvalidator and officeotron, neither of them are standard GNU projects but Java beasts. So even if I and a number of other developers do use this option, it happens from time to time that we need to fix new validation regressions, as others don’t see the problem; and even if we point it out, it’s hard to reproduce for the author of the problematic commit.

This has just changed, all you need is to get export-validation/setup.sh from dev-tools.git, and run it like this:

I.e. the first parameter is a working directory and the second is a directory that’s writable by you and is already in your path. And then wait a bit… ODF validator uses maven as a build system, so how much you have to wait depends on how much of the maven dependencies you already have in your local cache… it’s typically 5 to 15 minutes.

Once it’s done, you can add --with-export-validation to your autogen.input and then toplevel make will invoke odfvalidator and officeotron for the above mentioned documents.

The new year is here, if you don’t have a new year’s resolution yet — or if you hate those, but you’re willing to adopt a new habit from time to time — then please consider --with-export-validation, so that such regressions can be detected before you publish your changes. Thanks! ;-)

TL;DR: see above -- a number of preset shapes are now rendered correctly at any scale factors, where previously rendering problems occurred.

fdo#87448 has a reproducer document that shows rendering errors with the scaled cloud preset shape definition. At first I thought that the OOXML spec has wrong definition for this shape type, but that turned out to be not the case. What was a problem is our implementation of the drawingML arcTo command. This implementation defines how we render such arcs as polygons when the shape is to be painted, and given that LibreOffice has native support for the drawingML arcTo / ODF G command, this implementation is invoked during rendering, it’s not an import/export problem.

The rendering result looked like this before:

The cloud is drawn using a set of moveTo and arcTo commands. MoveTo is easier, as it uses explicit coordinates, but arcTo is more complex. It has 4 parameters: the height and width of a "circle", and the start / end angle of an arc on that circle. (Of course if height and width do not equal, than that’s no longer a circle… ;-) ) The problem is that due to this, the distance vector between the arc’s start and end points is implicit — so if something is miscalculated, errors are nicely added to each other as more and more arcs are drawn. This is especially a problem if you later return to the end of an earlier arc using moveTo: if arcTo has some problem, then it’ll be clearly visible.

After fixing UNO ARCANGLETO to only take care of scaling / translation only after counting the actual arc, we started to produce correct end points for the arcs and shapes started to appear correctly at any scale factor, yay! :-)

One remaining problem was how to test this from cppunit, in the above commit I exported the shape to a metafile, and then I could use Tomaž’s excellent MetafileXmlDump to assert that the end of an arc (implicit location) and the parameters of a moveTo command (explicit location) equal — when they do not, that’s what your eyes call a "rendering problem".

As someone who usually hacks on LibreOffice, external import filters produced by the Document Liberation Project cut both ways: they are great, as they deal with obscure formats and we get them for free, OTOH hacking such code is more complex than the usual LO code. I recently contributed a few patches to libvisio and libodfgen, but before I was able to do actual code changes, I had to set up a number of repositories and configure them to talk to each other — this post describes one possible setup that suited my needs.

(bookline, de a lira.hu is árulja DRM-mentes ebookban)

It turns out LibreOffice’s RTF and DOCX import filter ignored borders around Writer pictures. Given that this worked in the RTF case in the past, it’s a bit amusing that now the very same commit implements a new feature for the DOCX case and at the same time fixes a regression in the RTF filter. Code sharing FTW! :-)

Végre egy film ami nem romantikus vígjáték, nem háborús dráma és még nem is bántam meg a rászánt időt. Persze nem is véletlenül kapott 10-ből 8.2 pontot. ;-)

(imdb, trailer)

UPC traditionally had a setup consisting of a cable modem providing internet access to a single computer, and then it was up to the users if they use that access to really connect to a computer or to a router, providing wireless access and so on. It seems, these days they are more after actually encouraging people to use their subscription on multiple devices — possibly that way it’s easier to sell larger packages (like 60 MBit/s download rate instead of 30 MBit/s, etc). One fallout from this move is that they started to replace modems with a combination of modems and routers, in this case this is an Ubee EVW3226, with the brand removed. I wanted to try out if this new device could replace my previous router or not — so far it seems to be good enough, though there was one pitfall, hence this post.

It’s possible to define a range of IP addresses to be used for DHCP purposes, though you can’t serve fixed IP addresses based on the MAC address of the clients. Given that my home network isn’t that large, I can tolerate that: as long as there is a range that can be safely used for fixed addresses, I can configure that manually. It’s also possible to do port forwarding, e.g. redirecting the incoming ssh traffic to a given address — except you can’t do both at the same time: you can’t redirect traffic to an address that’s not known (served via DHCP) to the router. Which is a shame, the #1 use case for port forwarding is to redirect traffic to a home-server that will then also have a fixed IP internally…

So here is a hack that allowed me to still do this: set the start of the range of the DHCP served IP’s exactly to the address of the (to be used in future as) fixed address, e.g. 192.168.0.5. Connect with one client, so that the address will be known to the router. Then add the port-forwarding rule, finally set the DHCP range back to its original value (in my case I use 192.168.0.1..99 for fixed addresses and 100+ for dynamic purposes). It’s a stupid trick, but it works… ;-)