Tag Archives: Gnome


glibmm 2.38 and gtkmm 3.10

I just released glibmm 2.38.0 and gtkmm 3.10.0 – stable releases of API that we’ve been working on for a while.

This adds several new widgets that were added in GTK+: HeaderBar, ListBox, PlacesSidebar, SearchBar, and Stack. Thanks to Juan Rafael García Blanco, Andrew Potter, and Kjell Ahlstedt for that hard work.

It deprecates StockID, Table, IconFactory, IconSet, IconSource, and Gdk::Color along with several methods.

This glibmm release also has a fairly useable API for Gio::Menu and Gio::Action so you can really create gtkmm Menus with them and Gtk::Builder (here is an example). But unlike GTK+, we decided not to deprecate Gtk::UIManager, Gtk::Action and friends yet.

Most importantly, and most difficult to notice, we have deprecated deriving from Glib::Object before deriving from interface classes (such as Gtk::TreeModel). So you need to make changes such as this. The previous use of interface classes as the last base classes, after Glib::Object (which used to be the only way to use them) will cause runtime warnings in glib for now, and will probably break your application’s functionality in future glib versions. It’s not what we want.

gtkmm 3.8

I didn’t get around to blogging about gtkmm 3.8 when I released it last month, partly because we had to fix a crasher bug and do a gtkmm .1 release before people noticed.

Anyway, just a little while after GNOME 3.8 was released, we managed to release gtkmm 3.8 and glibmm 2.36. There is quite a bit of work in these, almost all by José Alburquerque and Kjell Ahlstedt, as well as the usual few days of last-minute work by me to wrap remaining new API.

I spend very little time on glibmm and gtkmm these days, and don’t have much motivation to change that.

There’s also a change that we expect in glib 2.38 that will break many installed applications that use gtkmm. We successfully begged the glib developers to add a special case for us in glib 2.36, but we have not found any way to avoid this for 2.38. So far our best option seems to be to do a new parallel-installed gtkmm (and glibmm) ABI, leaving the old (broken with glib 2.38) one behind, at least allowing applications to be changed slightly and then rebuilt.

Personally, I have no great incentive to go through that pain.

More Maliit Keyboard Improvements: QtQuick2

A few days ago I pushed 44 more commits to the Maliit Plugins repository now that Canonical have published (in the Ubuntu Phablet project’s maliit-plugins Launchpad/Bazaar repository) that work that we (Openismus) did for them.

This brings the Maliit Keyboard into the QML/QtQuick2 world for Qt5, removing the use of QGraphicsView which is not really suitable for Qt5. This should also have some performance advantages and makes customization even easier.

Michael Hasselmann blogged a summary of the state of Maliit today. The recent work, along with the Wayland integration, has made Maliit more popular than ever.  But we still need to line up customers to fund the ongoing development, generally while creating custom features or solutions for them.

Maliit Keyboard Improvements

On Friday I pushed 194 commits to the Maliit Plugins repository, adding new features, bugfixes, cleanups and tests to the Maliit Keyboard. This is some of the work Openismus has done for Canonical over the last few months which we are now allowed to upstream. This includes hard work by Michael Hasselmann, Krzesimir Nowak, Jan Arne Petersen and Jon Nordby.

Our work on the underlying Maliit Framework for Canonical was published upstream as we did it. We believe we’ll be able to upstream more of our Maliit Plugins work in the future.

Versions of these Maliit Plugins commits were published a few days ago in the Ubuntu Phablet project’s maliit-plugins Launchpad/Bazaar repository. It also contains commits (not by us) on maliit-plugins’ Nemo Keyboard, mostly for integration with the Ubuntu Touch platform (and its use of Android’s Surface Flinger). The recent Ubuntu Touch preview is using a version of that Nemo Keyboard, though we believe that’s meant as a temporary solution. A properly integrated Maliit Keyboard should behave significantly better.

Anyway, these commits add these features to the Maliit Keyboard:

  • Auto-capitalization.
  • Styling, such as a black underline for the current word and a red underline for a word with an error, though its up to the toolkit exactly how it shows this.
  • Word prediction, error correction, etc are now available when editing previously-entered words, instead of just the next word, taking into account the surrounding words.
  • Users can add words to the dictionary with a long press on the space key.
  • More settings to enable/disable auto-capitalization, auto-correction, word prediction, error correction, audio feedback and whether the word ribbon should be disabled in portrait mode.
  • Applications can specify text and icons for actions keys, such as Done, Go, Login, etc.
  • Keyboard themes can now specify fonts.

The maliit-plugins NEWS file gives more details.

Many of these features were already in the old MeeGo Keyboard (used by the Nokia N9) which had to be dropped last year because of its libmeegotouch dependency and its need for proprietary plugins to achieve these features.

We hope to have all this in an official Maliit release soon.

Rygel Documentation

Over the last few months, I have worked on Rygel‘s documentation, along with Krzesimir Nowak and Jens Georg here at Openismus. Most of that work is now finished. It’s been a great investment of time that should be of real benefit to the project.

We’ve massively improved Rygel’s (C) API documentation, which was rather bare after Rygel’s initial split into shared libraries. We had to investigate how the current plugins use the API, and sometimes improved the API in response. (The very latest API documentation improvements will be online soon, when we do a new Rygel release.)

We’ve added both simple and real-world examples, linking to them from sections in the API documentation and describing how those examples work. Those real-world examples are standalone GStreamer-0.10-based versions of the regular Rygel media engine and of its media-export server plugins, plus a GStreamer-0.10 version of the standalone renderer example.The original code for these (now using GStreamer-1.0) was in Vala, like the rest of Rygel, so we had to convert them to C. To maintain functionality, we chose to clean up the horribly-obfuscated C code generated by Vala. That took us a few frustrating weeks to finish but we got it done.

The new Rygel Integration page provides an overview of the APIs that platforms should find interesting, linking to the various documents that we’ve created during this effort. That Integration page is part of a complete overhaul of Rygel’s wiki project pages to make them more attractive and useful.

To help with maintenance of Rygel itself, we now have a Rygel Architecture page with descriptions of Rygel’s program flow in various situations, and a Rygel architecture diagram showing how the various parts of Rygel work together.



Glom: Experimental MySQL Support

Glom uses PostgreSQL and doesn’t try to offer the user a choice of anything else. That’s because it does what Glom needs, there’s no need to confound the user with an incomprehensible choice, and I’ve no wish to maintain multiple sets of code. It’s hard enough keeping up with changes in PostgreSQL, though Glom’s regression tests help.

However, I played around with adding MySQL support as a build-time alternative via the –enable-mysql configure option. The basic stuff now works both in the UI and in the regression tests. Those tests can now run each self-hosting database test with all 3 backends.

This is mostly just so I could learn about MySQL, so I can reimplement it in Java for OnlineGlom. That would let me use Google’s Cloud SQL, which is based on MySQL. The main work has been figuring out how to initialize a MySQL database store on disk and then start and stop MySQL instances. It’s even more funky than with PostgreSQL. I did need an addition to libgda to support non-standard MySQL port numbers but, as usual, Vivien Malerba fixed that for me quickly. There’s also the rather huge problem that AppArmor on Ubuntu prevents us from starting MySQL with anything but the standard database data, and we can’t expect the user to go editing AppArmor config files. At least with MySQL 5.6, it should be possible to start a MySQL instance without it having no password for a few seconds, as is necessary with MySQL 5.5. I need to start and stop custom instances so I can run tests automatically.

I’ve committed it to Glom’s git master, and its in the 1.23.3 release, just in case anyone wants to improve it. There are some TODO_MySQL comments in the tests where we expect something to fail with MySQL. For instance, I have not added support for editing the MySQL users and groups. And there are likely to be problems with keeping data when changing field types, which doesn’t seem to be tested thoroughly for any backend. libgda is also missing some support for binary field types, needed for Glom’s image fields.

Over the years, various people have complained about Glom not using MySQL. Here is your chance to actually work on that, with tests to show if your work is enough.

Programming For Kids

I tried a couple of applications with my four-year-old son: Pictomir and MIT’s Scratch.

Neither seem particularly well maintained and neither are suitable for young children without lots of supervision. Pictomir is easier to get started with, but not easy enough. Scratch is probably more interesting to older children, though they’ll partly be learning about how software is still so often arbitrarily annoying, and I’d prefer that they were introduced via a better example. I’m very tempted to write something better.


Pictomir at first start up.

Pictomir leads the child through a series of levels, telling an R2D2 robot (Don’t tell George Lucas) to move around some isomorphic squares to paint some tiles. At the beginning the program exists and the child just needs to click the play button. In subsequent stages the child has to build part of the program himself, and then all of the program.

The available commands, at least at the start, are icons for left-turn, forwards, right-turn and paint at the top of the screen. These may be be dragged into the available boxes in the program at the right of the screen, though you can instead put them there by clicking to select and then clicking on the empty box in the program. However, the available commands are far away from the program where you must place them, so the child has to spend lots of time moving the mouse pointer back and forth across a wasteland of empty space.

I found an official Ubuntu package in the developer’s PPA. It was last updated to Ubuntu 10.10 (Maverick), but you can install it manually on later versions. All of its UI is in Russian, though you can ignore most of it because the UI is icon-based. When I built the newer code from source a few months ago, I think the UI was translated.

I guess that Pictomir was developed for a specific screen size and generally older PCs. It does not scale the playing area up, so the child has to deal with a tiny R2D2 on a tiny grid in the middle of wide empty space.

pictomir has a bare svn repository, though I can’t see how clean its commits are, and I don’t know if it’s still used. There are no commits since last year. My svn says that the svn format is too old to check it out, though I’ve checked it on on previous Ubuntu installations.

It’s website it quite awful (and only in Russian). I only discovered Pictomir thanks to commenters on Google+.


The Scratch UI has several problems that make life hard for the child:

Scratch, after creating and running a small program.
  • Scratch requires the child to cope with tiny targets (See Fitt’s Law)
  • Scratch demands the use of drag and drop. This is frustrating for normal users, let alone children, and really hard with some laptop touchpads or trackpoints.
  • Update: Scratch requires the child to understand the difference between left-click and right-click. Right-click brings up a help context menu, which just causes confusion.
  • Update: The tiny commands have tiny text edit boxes. Children have a high chance of clicking it instead of clicking the command block itself. This problem could be partly solved by accepting drags on the edit box.
  • Scratch requires the child to double-click (see below).
  • The commands require the children to read, but a subset of the commands could instead be respresented by icons. The words are particularly hard for beginner readers because they are written in such a tiny font.
  • To get started with scratch, you need to figure out that you need to double-click on the first program command to actually start your program. There is no simple run button. You can cause your program to be run by clicking the green Flag button, but that’s something you need to put in your program.
  • When you try to move a command around in the program, it moves the command and all subsequent commands, as a group. So moving just one command means moving stuff around and then moving some of the stuff back to where you started.
  • Your program moves the Scratch cat sprite around the canvas, but that canvas is tiny, and the sprite can move off screen. The only way I found to get it back was to double-click the set-x-to and set-y-to program commands. I can figure that out, but beginners will not.
  • When you’ve drawn all over your canvas, the only way to wipe it is to go to the Pen set of commands and double-click the Clear command.
  • The sprite moves far too fast for the child to understand the relationship between the commands and the motion, without someone explaining it. If the command says move-10-steps then I’d expect the sprite to visibly move 10 steps. Advanced users might prefer it to be faster and smoother, but the default should make things obvious.

There are some other strange things in the UI which are probably a side-effect of its eccentric (Smalltalk) implementation.

  • Scratch has a menu (well, an icon-menu) for changing its language, instead of just using the user’s regular language.
  • None of the UI elements (menus, tabs, buttons, file chooser dialog, etc) match other standard applications on the system.

I think Scratch could be really popular with younger kids if it ran on Android with a touch interface and with less text, maybe as a simpler version. But the developers don’t seem to have any interest in that – they seem to be working on a Flash-based version of Scratch for the web, which is unlikely to work well with touchscreens, even if they can get Flash to work on Android and iPhone (they won’t). And I have no interest in hacking on Smalltalk. There seem to be various programming-language-based forks of at least the underlying engine, but none seem to be successful.


gtkmm maintainership

I have not had enough time recently for my maintainership of gtkmm, glibmm, libxml++ and libsigc++. And I’m unlikely to find time soon. Family and (income earning) work have taken priority. That’s why glibmm and gtkmm didn’t have .0 releases until a couple of weeks after the GNOME .0 release, and why there was no real attempt to follow the GNOME release schedule this time. I’ve hardly touched cairomm for years.

It’s not a lot of work but I’ve had to find a few days every few months to keep glibmm and gtkmm up to date with API additions in glib and GTK+, to keep roughly in sync with them. There has been rather a lot of new API recently. See the list of new API in gtkmm 3.6, glibmm 2.34 , gtkmm 3.4, and glibmm 2.32. Krzesimir’s ongoing attempt to use the introspection information (rather than .defs files) would help with this but not hugely because we’d still need to take care that the API is right for C++. Some initial .hg/ccg creator script would probably be most helpful.

I have no time for the more difficult bugs that turn up occasionally. Luckily Kjell Ahlstedt, José Alburquerque and others arrive regularly in bugzilla with great fixes for hard problems. I trust Kjell and José to commit directly, but they deserve some decent patch review. Unfortunately I often keep them waiting far too long.

I need to make some change. As a start, I might stop receiving bug email for glibmm and gtkmm, and stop worrying about adding new API. I guess it will take at least one missed GNOME release cycle for some other people to take over my responsibilities.