Category: Work

Hello Oslo, Hello Squarehead Technology

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Two years after moving to Berlin and joining Openismus, it is time for another big change. I learned a lot while at Openismus, and had a lot of fun both in and outside of working hours. Those of you who have been to the barbecue parties know what a great bunch of people they are. I’m very glad to see that they are now going strong again.

In December I will join Squarehead Technology in Oslo as a Software Developer. There I will work on their advanced microphone array systems for acoustic cameras and acoustical zoom. The role includes both real-time programming, digital signal processing of audio/video and embedded Linux, which is pretty much exactly what I was looking for.

Here is a very quick demo of the technology, used for noise analysis: Nor 848 video

The array microphone system records 200+ channels of audio simultaneously. By exploiting the time difference between channels, digital signal processing can extract and/or visualize audio content at different positions in the recording. This can be done both in real time, and in retrospect (unlike parabolic microphones).

Fun times ahead!

Application-hosted and compositor-hosted Maliit

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The standard way of deploying Maliit is to have a single maliit-server instance (per user session), hosting the actual input method (virtual keyboard, handwriting). Applications then communicate with the server (and by extension, the IM) through an IPC.

This allows for a single instance of Maliit to serve all applications, which is memory efficient and robust. A crash in a Maliit IM plugin cannot take down the application and risk loss of significant user data. The disadvantage is the increased system complexity (a separate server process needs to be running at all times*) and requiring compositing of the application and input method windows. The latter can be quite challenging to do in a well-performing way on low-powered mobile/embedded devices. See Jans blogpost for how we handled that on the Nokia N9.

* By default we make use of DBus autostarting, of course.

Application-hosted Maliit

To make Maliit more suitable for systems where only a single application runs (embedded) or compositing performance is not good enough, we now also allow Maliit to be “application-hosted”: the Maliit server and input method plugins lives in the application process, not a separate server process. Enabling this feature has been a long running task of mine: All the code in input-context and server was made transport independent, a direct transport (no IPC) was introduced, and setting up the server for a given configuration (X11, QPA, app-hosted) was simplified. Other motivations for this work include being able to run the server and IM plugin easily for automated end-to-end system or acceptance testing, or just to easily start the server with a given IM plugin loaded for quick manual testing during development (see Michaels merge request).

An example application exists as part of the Maliit SDK that demonstrates the feature: maliit-exampleapp-embedded

Maliit running in application-hosted mode: The Maliit Server and input method plugin is embedded in the application instead of running in a standalone server process.

This works by having a special input-context “MaliitDirect” which instead of connecting to the server over DBus, creates the server and a direct connection. As when running standalone the server will instantiate and manage the necessary input method plug-ins.

Because the IM does not have its own window in this configuration, the application is responsible for retrieving the IM widget from the server, and re-parenting it into the appropriate place in the widget hierarchy. For all other purposes the application uses the same interface as if the IM was hosted remotely, making sure the abstraction is not broken and that one can easily use the application with Maliit deployed in different configuration.

This feature currently works with Qt4 applications, and is in Maliit since the latest release (0.90.0). One issue is that with the current input method API, the plugin assumes a fullscreen window; overlays extending the base area of the IM will be clipped and size needs to be overridden. This is something we are fixing in the new improved API.

Compositor-hosted Maliit

Another approach to make rendering perform better is to host the input method in the process responsible for the compositing. This also reduces the number or processes involved in rendering/compositing, and the associated overhead. This could be a X11 compositing window manager (like KWin or mcompositor), but a more realistic use-case is a Wayland compositor (for instance based on QtCompositor).

The API allows the consumer to inject an class instance for the configuration dependent logic, allowing to integrate the Maliit server with the logic in the rest of the compositor. Applications will use the normal “Maliit” inputcontext and communicate to the server through an IPC like DBus.

After the work with application-hosted Maliit, this feature was completed by making the server and connection libraries available as public API. The API is available in the latest  Maliit release (0.90.0), but is considered unstable until Maliit hits the 1.0 mark.

 

 

 

 

Maliit on Windows: Basic build working

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Enabling third-party developers of input methods is one of the primary goals in the Maliit project. In an attempt to improve this story I spent some time on getting Maliit to work on Windows.

Since we use Qt there were few changes needed to the code, but since we use qmake, quite many to the build system. One of the bigger changes was making glib-dbus and qdbus  optional, which is also useful for Maliit on embedded systems.

With the Windows build fixes merge requests for maliit-framework and for maliit-plugins, one can now build Maliit on Windows and run the provided example applications. This feature is currently being reviewed and should be in the next Maliit release.

Thanks to the standalone viewer application for Maliit Keyboard this allows one to develop new features, theming and language layouts for it on Windows.

Sadly loading an input method plugin in the maliit server crashes for an unknown reason. With my limited Windows software development experience I was not able to solve this within the couple of days I had available. This is necessary for application-hosted Maliit to work and to enable general development of Maliit input method plugins (not just maliit-keyboard). Help would be much appreciated, even just someone checking  if it is reproducible on another Windows system.

Also left on the todo-list due to lack of time is to set up a Windows build slave for the Maliit buildbot, to test that the build continues to work on Windows and to produce executables.

The Maliit buildbot

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After having set up the typical things open source projects needs like a website/wiki, mailing-list and bug-tracker, Maliit now also has something not so common: a build-bot.

As Maliit consists of several components that can be built in several different ways (and for several different platforms), we wanted to automate the build and tests of the different variations to ensure that we do not break any of them. This is especially important for variations which are not easy to test for the individual developers, like for instance Maliit on Qt 5.

The software chosen to help with this task was Buildbot. Getting an initial instance it up and running was very quick and pain-free, especially thanks to packages being easily available and the excellent documentation. The current setup now builds, tests and installs the two major components we have: Maliit Framework and Maliit (Reference) Plugins, in the most important build/config variations we have. A total of 12 individual build jobs, plus 2 meta-builds. The configuration for the instance can be found in the maliit-buildbot-configuration repository.

For security reasons the build-bot is not directly exposed to the Internet. Instead a script runs every 5 minutes to generate a static HTML website and publish on the public web-server: Maliit build-bot

Buildbot says: All green!

This gives us a minimal continuous integration system for Maliit, which for now will hopefully helps us avoid breakage. In the future, the usage of the build-bot might extend to include:

  • Automating the release process
  • Testing of merge-requests/patches before merging to master
  • Automated integration/system testing, complementing the unit-tests
  • Triggering external builders for packaging. OpenSUSE OBS, Maemo 5 Garage, etc.
  • Automating certain aspects of bug-lifetime. Resolving when fix is committed, closing on release if pre-verified, etc

 

GTK+ application support integrated into Maliit mainline

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GTK+ application support for Maliit input methods has existed for a long time, but up until now it has lived in separate repositories. This has been inconvenient for users and for developers, and was the major cause for it to not be on the same level as the Qt support. This has changed as the GTK+ support has now been merged into the maliit-framework repository, and along side the Qt support. Maliit 0.80.8, which was released yesterday, contains these changes.

Maliit running on WeTab with Fedora 15, showing QML reference plugin and GTK+ application

Two implementations existed for Maliit GTK+ support. One was written by Javis Pedro as part of a Google Summer of Code project for MeeGo in 2010. His blog has several posts on the topic. The other implementation was maintained by Raymond Liu (Intel). This is the implementation shipped in Meego Netbook, and the one improved by Claudio Saavedra (Igalia) as part of the GTK+ on MeeGo project. It was also the only one that was updated to work with the DBus connection changes that was done quite some time ago, and supporting both GTK 2 and 3. For these reasons this was the implementation integrated into mainline Maliit.

Once the code was integrated, improvements soon followed. The application now correctly reconnects to server, and make install will automatically update the GTK+ input module cache on Ubuntu, thanks to Łukasz Zemczak (Canonical), and on Fedora. This means GTK+ application support will work out of the box, no twiddling needed.

While this is a huge step in the right direction, the GTK+ support is not as good as for Qt yet. Javis Pedros implementation has features that does not exist in mainline, so code/principles can hopefully be reused from there to implement these. This includes custom toolbars and attribute extensions, and content type hints for text entries. Other features looks hard to implement due to limitations/differences in the input context plugin architecture found in GTK+, and will probably need work in GTK+ itself to solve.

Example plugins for Maliit available

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In Maliit input methods are implemented as plugins. This flexibility is important because it allows the same framework to provide very different text input methods, without us having to implement them all. Different virtual keyboards, hardware keyboard input, handwriting, speech-to-text, input methods for accessibility, et.c. are all possible with the Maliit framework. This makes the input method plugin API the most important extension point.

To make it simple to start developing an input method for Maliit, we have written a set of example plugins that can be used as a skeleton* for a new input method. There is one “Hello World” example showing the C++ interface, and one showing the newly added QML interface. The latest documentation for the framework in HTML format is also included, along with a simple test application. How to get started is documented on our wiki page: Go!

A very conventional example: An input method that allows you to input "Hello World"

A nice thing is that these examples are in our framework repository: built as part of the standard build, with simple tests run as part of our test-suite. This ensures that the examples stay up-to-date and working, something I find that step-by-step, code-and-talk tutorials in some documentation repository/directory typically do not.

If you want to look at real-life examples of plugins, check out the Meego Keyboard code (C++), the Meego Keyboard Quick code (QML), or foolegg from maemo.org’s cute-input-method code (QML with Pinjyin support!). Also make sure to check out Michael Hasselmanns talk at the Meego Spring 2011 Conference: Developing custom input methods for Meego.

If you hit any issues, contact us through one of our communication channels.

* Note that currently the license of the examples is LGPLv2 like the rest of the framework.

Introducing; Maliit on-screen keyboard in Gnome 3

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Maliit (also known as Meego Input Methods) has the following overall goal: “to be the input method project for MeeGo and other GNU/Linux-based embedded/mobile platforms”.

This initial video shows Maliit running in Gnome 3, and demonstrates some of the very basic features provided by Maliit and the standard keyboard shipped with it. The demo is done on a WeTab tablet running a standard Fedora 15 Beta, with the latest Maliit software installed. Jan Arne Petersen is working a bit on  Fedora packages, so hopefully it will soon be easy to install for those who are interested.

Some more info about the features shown in above video:

0. Theming. Using the theming support in the standard Maliit keyboard, it is easy to go from a mockup to ready implemented theming. This theme was based on the mockup from live.gnome.org (by Jakub Steiner I believe?) and done by Michael Hasselmann in a couple of hours. He also has a blogpost on how the theming system works.

1. Typing text.This is of course the number one feature of an on-screen keyboard. There are some essential best-practice and some tricks used in Maliit to be able to get really good reponse time and typing speeds. I hope we will have some blogposts about that soon.

Typing speed can be further enchanced by enabling multitouch support (not working out-of-the-box in Fedora due to missing support further down the stack), or by installing a prediction/correction engine. User feedback can be enchanced with audatory and tactile feedback (requires hardware and driver support obviously).

2. Different languages/layouts, and switching between them. Maliit comes with layouts for over 20 languages, tested and tweaked by usability experts. Latin, Cyrillic, Arabic and Chinese based scripts are covered. The layouts are defined by XML files, so one can easily change them if wanted.

Chinese ZhuyinRussian

Arabic

For more of the features offered by Maliit framework and standard keyboard, see the wiki page. If you are interested in improving Maliit, or its integration in Gnome 3 or other GNU/Linux environment, join the irc channel or mailing list.

Next up; the importance and difficulties of input method integration on touch enabled devices.

Meego Conference 2010

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Like most of my colleagues at Openismus I was present at the first Meego conference in Dublin. As usual, I’m probably the last to blog about it. See for instance Friedrich’s post, Andre’s post or Chris’ very detailed post.

The conference was held at the Aviva stadium, a huge sports stadium just outside Dublin center. Untraditional venue choice, but it was quite nice and the organization was very good.

The conference schedule was packed; 2 days with 5 parallel tracks and the third day done unconference style with some 7 parallel sessions (btw, all the talks are available online). Many of the technical talks I went to were a bit on the light side in my opinion, which is forgivable considering how new the whole Meego thing is (or maybe I just chose badly). However, the keynotes and some less-technical talks (and some discussions in the “hallway track”) gave me much better understanding of what Meego actually is and aims to be.  Which is arguably just as important.

The schedule was fairly packed in the evenings as well, with opening reception and  “Openismus conference dinner” at the closest pub the first day, party at the Guinness Storehouse the second and a Ireland-Norway friendly in football (which Norway won!) the third. In addition, the official conference hotel had a “hacking area” available 24-7, which was pretty popular.

To give Meego a little boost,  all the participants were given a Lenovo Ideapad S10-t3 tablet netbook/laptop. In exchange we had to install Meego Netbook Edition 1.1 on and promise to develop cool applications for. Lucky me also got a Nokia N900 so I can do development for that form-factor as well. 😀

What is Meego? (my interpretation and some musing)

At least Intel seems to have a very clear vision of  Meego as an open operating system and software platform that will make it easy for people to deliver new and innovative products in the embedded/mobile/space.

Meego explicitly targets a broad range of device classes, from set-top boxes to in-vehicle-infotainment to handsets to netbooks, a very bold move. Personally, I think the key to succeeding in that aspect is to attract the vendors with expertise in each device class and have them drive development. The project has done a decent job at that so far with Intel, Linpus, et.c. for netbook, Nokia for handset, the GENIVI consortium for IVI and so on.

Another thing the Meego project explicitly supports is for vendors shipping devices to do customization. This is basically a prerequisite to be able to attract them at all (as they naturally want to differentiate their products), but brings additional challenges in delivering a consistent platform and brand. The compliance specification work presented at the conference leads me to believe that the project is on the right path here though.

As an application platform Meego is based around Qt (with Qt Quick). This is a decent platform, but what is most lacking in order to attract application developers is probably shiny, attractive devices, and people using them. Hopefully they will be here soon…

All in all, I like what I see. Time will show how well the project succeeds, there are certainly exciting times ahead!

Playing with Qt Quick; Imago

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In learning Qt, I of course needed to get some experience with the newest and shiniest bits of Qt: Qt Quick.

One of the things I’ve done with that is to make a simple application, an image viewer called Imago. The code can be found at Gitorious. It is a bit different from typical Qt Quick applications as it is not a mobile application but rather targets the desktop. Thus I’m using standard desktop UI concepts like drop-down menues, and ordinary file-chosers.

Imago - single image view

Imago - single image view

Imago - "traditional" view

Imago - "traditional" view

Imago - grid view

Imago - grid view

The lists can be “flicked” through using the pointer, or using the scroll wheel. Moving between the views that show multiple images and the single-image view has a small animation.

Implementation

In a Qt Quick application two languages and runtimes are involved; C++ and the declarative language that forms the basis of Qt Quick, QML. Qt supports bi-directional communication between the two using a number of metods.
In my case I chose to make a QObject class that  maintains all of the central state in the application. This includes things like what folder is currenty open, the images in that folder, which image is currently focused/selected. All these attributes are implemented as QObject properties, and are notifyiable (meaning they have an attached signal that you guarantee to emit each time the value changes). Exporting this object to QML then allows these properties to be used in property bindings, or for one to connect to the notification signals.
So in Imago QML is basically used as a “stupid” UI layer for the image view. Other things, like window title and drop-down menues are handed by the C++ side, but by using the signals and properties of the same object.

Writing a desktop application means that one cannot assume a fixed window size like people tend to do for mobile device applications. With setting the resize property of the QDeclarativeView (the widget that displays the QML stuff) to QDeclarativeView::SizeRootObjectToView and using anchor layouts throughout this is possible, but it took me a good while to get working properly. Mostly because the concepts are new, and most (all?) the examples in the documentation seem to neglect this aspect.

The grid and traditional view are actually implemented in different QML files (though the delegate for the images in the list is shared). I did this to test how having several UIs would be like, and for a simple application like this it works out just fine.

Where to now?

Imago right now is very simple,  and could benefit from some added features and some designer love. I also just found a bug in the traditional view that needs to be fixed. I have documented these things in the README file in case someone is interested. As I have moved my focus over to other projects, I probably wont be taking this application much further, at least not at this time.