10. Using Framebuffer Device (QVFB)

If you want to debug your programs or just dont have an ipaq available for test, you may want to run your programs on your LinuxHost.

Trolltech ships a tool called qvfb with all qt versions. This tool is used as a Vesa Framebuffer Simulation and is able to run qt-embedded programs under X.

This chapter describes, how to compile and use qvfb and how to use the tool for testing / debugging.

For detailed information regarding the use of qvfb, check the trolltech document page http://doc.trolltech.com/2.3/qvfb-qws.html or the 3.0 version instead.

10.1 Compilation and installation

Even if qvfb is shipped and used with qt-embedded, you hav to compile it using the "normal" X-Version of qt. I am using the qvfb shipped with qt-3.0.5 the last days but also older versions of qt worked.

To compile qvfb and install, follow the instructions.

1. compile your QT-X Version first from source. To do that follow the steps described in chapter qt-compilation.
2. Set the QTDIR environment to the newly created qt-version.
   export QTDIR=/whereYourQtVersionIs
3. change to subdir qvfb and enter make.
4. copy the result (qvfb) into /usr/local/bin (assuming your PATH shows there).

10.2 Run your own programs

Make sure, that LD_LIBRARY_PATH points to your embedded lib dirs (including eventually used user lib dirs). This can be ensured using your environment qtemb or qt-opieemb if proberly configured.

see also Opie embedded environment.

Change to qtopieemb environment.

Run qvfb & (may be you have to add -depths 16 or similar). QVFB is started, a window (240x320) with a black background is shown on your screen.

If you just want to test your application start the embedded version using /whereYourEmbeddedDirIs/yourapplication -qws. The application is launched and uses the qvfb window for IO. If you are over the window with your mouse, the hosts mouse can be used to control ypour program.

10.3 Run opie

If you are so far, you may want to run opie using qvfb. For this change to qtopieemb environment, cd to $OPIEDIR/bin and start ./qpe -qws.

Opie will be started using the framebuffer and all applications are included.

Note
Not really all functions will work (e.g. qcop), because your host system does not support this functionality. Also not all applications are startable, which require that kind of stuff.

Maybe the next chapter helps with that, when filled. The idea is to have also an embedded-familiar distro running on your host. Maybe chroot helps us with this, but I am not so far to have it running at this point.

If someone knows, how that works, help me please :)

10.4 Chroot system using familiar

need help for that.