Eclipse icons in menus are not showing in Ubuntu Maverick Linux

I don't like Gnome and I usually use KDE, but on a specific computer I have to use Gnome, and I noted that after switching to Ubuntu Maverick, icons on eclipse menus were not showing anymore.


I asked on some newsgroups with no luck, then on IRC I was pointed to this bug, which solved my issue :)

You need to enable icons in menus with gnome configuration. You find some ways to do that on that bug report, but I simply ran gconf-editor on the command line, and enabled that checkbox:


Now my icons in menus are back :)

Using Compiz in KDE 4

I've been using KDE 4 for some time now, and I was pretty happy with its own desktop effects. However, lately, I started to notice that kwin and xorg process were taking some CPU usage, and with graphic cards such as Intel GMA and ATI, the effects were not so smooth (while in Gnome with compiz they were much better). So I decided to try and use compiz with KDE as well; here's my (positive) installation and configuration experience.

First of all I installed all these packages

emerald libemeraldengine0 compiz compizconfig-settings-manager compiz-kde compiz-fusion-plugins-main compiz-fusion-plugins-extra fusion-icon

Then you found the compiz-fusion application in my KDE menu, in System. Run it, and you can set some configuration options with that icon, in particular, you need to change the window decoration to emerald, and the window manager (to compiz). Then you must select reload window manager.



To keep compiz as the default window manager when KDE starts, you need to change System Settings -> Default Applications -> Window Manager (by selecting Compiz).


Of course, now you can configure compiz settings with its setting manager, but I suggest you to use the simpler configuration manager, simple-ccsm, as illustrated here.

Now enjoy compiz! :)

PhpBibliography 1.1.0

This new release of PhpBibliography features some nice features:

1. First of all, themes are now supported so that the user can create his own theme (which will not be overwritten during phpbibliography updates), see this wiki page
2. icons for known file extensions are shown for uploaded papers (see the screenshot)
3. uploaded papers can be removed during editing
4. the action menu was improved with tooltips
5. search results can be shown also as bibtex

Merging Subtitles in Video Files with DivXConverter

I recently discovered this cool program, DivXConverter, which I didn't find in my Ubuntu distribution (you can download the .deb file, though, and install the required dependencies), but that's really useful and easy to use.

"DivX converter is a simple Mencoder frontend to Produce DivX Player Compatible AVI video format with the ability to merge subtitles . It support many video and audio filters and many presets."

Now, the interesting features I've just used is the ability of merging a subtitle file (typically .srt) into a corresponding AVI file.

Here's what to do (see also the following screenshot):

1. Add the avi file (and select the output folder and the compression, I left the default Normal compression)
   
2. Make sure to select Xvid in the "Video Filters" tab to make sure the resulting avi is compatible with dvd/divx readers (at least the with ones I own)
3. You can leave the default settings for Audio
4. Select the subtitle file (I set ASCII as the encoding)
5. Go back to the main window
6. Press "Convert" and enjoy the resulting AVI file

mounting none on /dev failed: No such device

If you're experiencing this error message at boot in Linux (e.g., after you recompiled the kernel in Ubuntu Lucid)

mounting none on /dev failed: No such device

don't be scared, the boot will continue and there'll be no problem (at least, I read in some posts); I never experienced problems even with this error at boot.
But if you want to get rid of it, just make sure that you have

CONFIG_DEVTMPFS=y

in your .config file of your kernel source directory.

mSoma a Qt client for SomaFM

Andrea Grandi proposed me a few weeks ago to try and develop a client for SomaFM, a streaming radio with near 16 different channels, available for free. Indeed we wanted to try to develop an application for our cool Nokia N900 smartphone. Since this phone is now based on my beloved Qt framework, I accepted with much pleasure.

The really cool thing was that, by relying on the qt-mobility APIs (new Qt APIs for mobile application developers), we could enjoy cross-platform developing: all the code that I wrote for this player was tested and debuged on my computer, as a desktop application. Then, we deployed on the Nokia N900 and tried it there (and it worked seamlessly).

For instance, this are some screenshots of msoma running as a desktop application (in Linux in this case):

And this is a screenshot of the application running in the N900 (taken from Andrea's blog post):

Which is just a recompilation targeting Maemo (with this respect, the Nokia Qt SDK, based on QtCreator, is really helpful when developing).

Of course, this is the very first version of this application, and surely the UI should be different in the desktop application with respect to the cellphone version (in order to be more usable in the mobile devices). But, as it is, it's already enjoyable (but I may be biased ;)

Source code is available on Gitorious and it's always updated with latest version we're working on. If someone want to test the application, it's available in extras-devel repository ("msoma" under Multimedia section) of N900.

In case you want to use it as a desktop application, please remember that you need qt-mobility. I blogged about the installation of qt-mobility in Linux.

We really want to thank, Rusty Hodge, SomaFM's founder, who provided so many details about SomaFM for developing our application (and of course we thank him also for SomaFM itself :)

We look forward to receiving feedback, patches, suggestions, and help! :)

Our maemo profiles:

• Andrea Grandi
• Lorenzo Bettini

Building Qt-Mobility in Ubuntu

Lately I started to try to develop applications for the Nokia N900, and the Maemo platform uses my beloved framework Qt :)

In particular, Nokia started to develop the Qt-Mobility Framework. Quoting from their white paper:

The Qt Mobility Project presents a collection of related software frameworks and interfaces. The objective being to deliver new Qt APIs for mobile application developers. Using these new APIs, developers will be able to create cross-platform applications targeting Maemo, Symbian and other platforms. This suite of features also has components that will be desirable to all users, not just those with mobile devices, so Mobility has advantages even for the desktop user.

Thus, I wanted to try this project also on my Desktop (after all the intent of this framework is cross-platform development), and tried to compile qt-mobility on my Ubuntu/Kubuntu desktop. Unfortunately, I experienced many problems which now I seem to have solved, thus I'd like to share the steps to build qt-mobility from sources.

First of all, when installing qt-mobility after compilation, some files will be created in your current Qt installation. Thus, since I wouldn't want to spoil my qt installation from ubuntu packages, which is installed in system path, I downloaded the new qt framework 4.6.3 from the Nokia download site, and installed it in a path of my home: ~/usr/local/Trolltech/qtsdk-2010.03.

Then, I installed some packages that are useful to build qt-mobility and to enjoy media contents such as mp3 and videos, relying on gstreamer (not all these packages may be necessary, but after some tests, at least these packages will make things work):

sudo apt-get install libasound2-dev libbluetooth-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev network-manager-dev libxv-dev gstreamer-tools gstreamer0.10-plugins-base gstreamer0.10-ffmpeg w32codecs ubuntu-restricted-extras gstreamer0.10-plugins-good freeglut3-dev

Then, you need to get the sources of qt-mobility, and I got them from the git repository

git clone git://gitorious.org/qt-mobility/qt-mobility.git

However, you may want to get the stable sources (e.g., from qt-mobility download).
Since I'm a big fan of "shadow builds" which won't spoil your source directory, I built qt-mobility in another directory of my home, separate from the directory where I have the sources of qt-mobility (in this example the sources are in ~/install/qt-mobility): ~/build/qt-mobility/qt-4.6.3 (I specified the qt version I'm building qt-mobility with, since I may want to experiment with different qt versions):

• cd ~/build/qt-mobility/qt-4.6.3
• PATH=~/usr/local/Trolltech/qtsdk-2010.03/qt/bin:$PATH ~/install/qt-mobility/configure -examples -prefix ~/usr/local/Trolltech/qt-mobility > output.txt

Note that I temporarily change the PATH environment variable so that the configure script will use my local qt installation; I specify that I want to build the examples, and I redirect the output in a text file. This will also allows you to see possible errors during the configuration step (e.g., missing packages). Note also that I will install (once built) qt-mobility in my home directory in ~/usr/local/Trolltech/qt-mobility.

Once the configuration step is successful, you can start building qt-mobility and then install it:

• make
• make install

During the installation, if you take a look at the output, you will note that some files will be added to your qt installation, e.g.,

• install -m 644 -p /home/bettini/build/qt-mobility/qt-4.6.3/features/mobility.prf /home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/mkspecs/features/
• install -m 644 -p /home/bettini/build/qt-mobility/qt-4.6.3/features/mobilityconfig.prf /home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/mkspecs/features/
  

This way qt-mobility will be integrated in your qt framework (at least, this is what I presume).

Now, you can test your qt-installation by running an example (which was built and installed), for instance the player demo or the weather demo:

• ~/usr/local/Trolltech/qt-mobility/bin/player
• ~/usr/local/Trolltech/qt-mobility/bin/weatherinfo_with_location

Now, let's try to see whether we're able to use qt-mobility in our programs.

We'll try to compile a very simple qt program using a class from the qt-mobility framework (QVideoWidget), though we won't do anything with that (just to see whether we can build the application).

here's the files of our project

myvideowidget.pro

QT += core gui TARGET = myvideowidget TEMPLATE = app SOURCES += main.cpp\ mainwindow.cpp HEADERS += mainwindow.h CONFIG += mobility MOBILITY = multimedia

mainwindow.h

#ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QMainWindow> class QVideoWidget; class QMediaPlayer; class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); private: QVideoWidget *videoWidget; QMediaPlayer *player; }; #endif // MAINWINDOW_H

mainwindow.cpp

#include <QMediaPlayer> #include <QVideoWidget> #include <QTextEdit> #include "mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { videoWidget = new QVideoWidget(this); setCentralWidget(videoWidget); }

main.cpp

#include <QtGui/QApplication> #include "mainwindow.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; w.show(); return a.exec(); }

now, you should run the qmake of your qt installation you've used to build qt-mobility, thus

• ~/usr/local/Trolltech/qtsdk-2010.03/qt/bin/qmake myvideowidget.pro

and then run make, hopefully you should get no error. Note that we haven't named our qt-mobility installation directory anywhere here; there's no need to, since your qt installation was modified by qt-mobility, so that qmake will set all the variables for include files and libraries also for the qt-mobility path! In fact, you should see these compilation command lines:

• g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_OPENGL_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/mkspecs/linux-g++ -I../../myvideowidget -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/include/QtCore -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/include/QtNetwork -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/include/QtGui -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/include/QtOpenGL -I../../../../usr/local/Trolltech/qtsdk-2010.03/qt/include -I/home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/include/QtMultimediaKit -I../../../../usr/local/Trolltech/qt-mobility/include -I../../../../usr/local/Trolltech/qt-mobility/include/QtMultimediaKit -I/usr/X11R6/include -I. -I../../myvideowidget -I. -o mainwindow.o ../../myvideowidget/mainwindow.cpp
• g++ -Wl,-O1 -Wl,-rpath,/home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/lib -Wl,-rpath,/home/bettini/usr/local/Trolltech/qt-mobility/lib -o myvideowidget main.o mainwindow.o moc_mainwindow.o -L/home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/lib -L/usr/X11R6/lib -L/home/bettini/usr/local/Trolltech/qt-mobility/lib -lQtMultimediaKit -lQtOpenGL -L/home/bettini/usr/local/Trolltech/qtsdk-2010.03/qt/lib -L/usr/X11R6/lib -lQtGui -lQtNetwork -lQtCore -lGLU -lGL -lpthread

Now you can enjoy qt-mobility in your desktop :)