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.
Gegl is an image processing framework used in projects like Gimp and DarkTable. It will eventually allow Gimp to allow non-destructive, high bit-depth image processing, among other things. And GStreamer is the multimedia framework for GNU/Linux, handling video/audio/other playback/recording/manipulation on your favorite desktop/server/mobile/embedded system.
After writing the Cairo overlay GStreamer element, I implement a basic GStreamer element which allows you to apply a filter to video in a GStreamer pipeline using Gegl. Using this element, video editing/manipulation applications like Pitivi could allow users to apply effects provided by Gegl to videos. Gegl is a very powerful image processing framework, and already has a significant number of image processing operations. More operations is expected, especially from the port the tools, filters and plugins used in Gimp to Gegl.
Here are some screenshots showing the standard GStreamer video test data being manipulated in different ways using Gegl. Note: the size of the images are only different because the output windows had different sizes when I took the screenshot.
Top left: original video (no-op). Top right: color temperature adjusted from 6500 to 9000K. Bottom left: inverted colors. Bottom right: inverted colors and black-white threshold conversion
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.
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.
So, it is confirmed, I’m going to LGM 2011! I was at LGM last year, and I expect this year to be just as good. Hopefully I’ll also be giving a talk this time, about MyPaint and/or OpenRaster.
If you are interested in free and open source graphics software, or the production of freely licensed graphical works, you should go too! See the press release for more information, or go straight to submit a talk proposal. If you cannot be there but still want to show your support, please consider donating.
I guess this means I should order the tickets soon…
I wrote the initial version of this in late January, and after some interations it was merged yesterday to gst-plugins-good, and will be in gst-plugins-good 0.10.33. This solves the feature request I filed in 2009, one of my oldest bugreports in bugs.gnome.org!
What does it do?
cairooverlay allows you to draw arbitrary things on top of a video stream in GStreamer using Cairo. Previously you had to create a custom GStreamer element for that (in C/Vala), but now you can just hook up to some signals, using any programming language with GStreamer/Cairo bindings.
To draw an overlay using this element, you use the “caps-updated” signal to get information about the video stream (like width and height) and the “draw” signal to do the actual drawing. In addition to the Cairo context, the draw signal passes you the timestamp and duration of the buffer, so you can also do animations.
For more info see the included example application or the documentation (should be updated soon). Here is the obligatory screenshot showing the example application drawing a heart onto a test videostream:
The heart is actually animated, so I guess I should have had a video. But you’ll just have to trust me that it is very cute, or grab the code yourself!
Last weekend I was in Brussels for my first FOSDEM.
Friday I attended a planning meeting for this years Desktop Summit. Several things were on the agenda, the most pressing being the website and the call for papers which both should be finished in the coming month. I was tasked with organizing the call for BoF/meetings/devrooms. In a broader scope, I see my role as making sure relevant non-KDE and GNOME projects know they are welcome. People involved in such projects are welcomed to submit talk proposals, or apply for space for a BoF/meeting just like a KDE/GNOME project, but for anything to come out of it we need to communicate this properly.
Didn’t go to a lot of talks, but I had plenty of good discussions in the “hallway track” and in the evening events. Especially good was meeting up with Claudio Saavedra to discuss Meego Input Methods and the Gtk+ integration he is working on. I hope I was able to help him a bit in getting started.
Attended the Libre Graphics Meeting planning dinner sunday evening. I don’t know if I’m able to make it to the conference yet, so I did not have that much to contribute, but I let them that Libre Graphics projects are welcome to the Desktop Summit. And that I might try to organize a MyPaint workshop at LGM.
It is not well communicated, but you can apparently write your own “tabs”/”panes” for the panel/toolbar found in the Meego Netbook UX. Hopefully this blogpost helps a tiny bit*.
As stated by the libmeego-panel/docs/README in the source tree of mutter-meego there are convenience APIs for GTK+ and Clutter based implementations. But it seems you can also just use the DBUS API, in case you prefer Qt or something else. I found this out by searching though meego.gitorious.org after someone asked on #meego
*Since this should be documented in the platform API, I’ve of course filed a bugreport.
When I got back from the Meego conference, I tried building MyPaint on the Ideapad I got (which runs Meego Netbook 1.1).
I was pleasantly surprised to find pygtk in the core repositories. numpy on the other hand was missing but that was easy to build from source. Buut, it seems that pygtk is built without numeric support, making MyPaint unusable; numeric support is used to get access to the pixels in pygtk pixbufs, which we need for several central things.
I have of course filed a bug for this so hopefully it will be resolved soon. If not I will have to provide alternative pygtk packages using the community OBS. In any case, expect it to be working soon.
I also hope to adapt MyPaint’s UI to the handset and netbook/tablet form factor, but this is only talk so far.