User:Jketreno

Random tidbits of information about projects I'm hacking on...

Contents 1 multi-point-touch 2 enabling a native application 3 enabling a QML application 4 qml-gesturearea

multi-point-touch

During the MeeGo Conference I gave a presentation on multi-point-touch support on MeeGo (overview and video slides). As mentioned during that presentation, to add multi-point-touch to Qt applications running on top of MeeGo 1.1 requires a few changes.

The components that need to be changed are:

• Kernel -- You need kernel touch drivers that are in sync with upstream
• Qt -- You need a version of Qt that does not have the RX71 code path enabled

New components:

• mtdev -- Library to translate kernel protocol A and B to protocol B, adding tracking information
• xf86-input-mtev -- X input driver that communicates with mtdev to obtain multi-point data from the kernel
• multipointtouchplugin -- in-application plugin which hooks to the Qt input event filter to process XInput events sent from xf86-input-mtev and injects QTouchEvent's into the Qt event queue

To get the above, you can add my home project:

cd /etc/zypp/repos.d
sudo wget http://download.meego.com/live/home:/jketreno/Trunk/home:jketreno.repo
sudo sed -i -e 's,^gpg,#gpg,g' home:jketreno.repo
zypper refresh

Next, force a re-installation of the packages provided from my home project:

zypper install -f --from=home_jketreno kernel_netbook libqt* qt-qmlviewer mtdev \
       xf86-input-mtev multipointtouchplugin

It will prompt you to switch to the versions of the various packages provided from the above repository. Accept the changes, and reboot.

enabling a native application

The mechanism to talk to the xf86-input-mtev driver is not merged into the Qt package itself. Until that occurs, applications interested in working with touch events need to add the following to the beginning of their application, within the main() function:

foreach (QString path, QCoreApplication::libraryPaths()) {
    QPluginLoader loader(path + "/libmultipointtouchplugin.so");
    loader.load();
    if (loader.isLoaded()) {
        loader.instance();
        break;
    }
}

At the beginning of the file, you also need to include QPluginLoader:

#include <QPluginLoader>

And that's it.

enabling a QML application

The version of qmlviewer built and installed with the Qt package in my home project has the above code enabled, providing Touch events into qml applications run within qmlviewer. If you are loading your QML application using your own native loader, you will need to follow the steps above for enabling a native applications.

qml-gesturearea

As Frederik Gladhorn indicated during [his talk http://conference2010.meego.com/session/gestures-qt] at the MeeGo Conference in Dublin, the folks over at Qt have been working on an improved QML GestureArea component.

You can pull and play with what they're cooking as follows:

git clone git://gitorious.org/qt-labs/qml-gesturearea.git
git clone git://gitorious.org/qt-labs/qml-gestures-examples.git

To build qml-gesturearea, you may need to patch it (I did):

cd qml-gesturearea
sed -i -e 's,q->timeout(),700,g' qdeclarativegesturerecognizers.cpp
qmake
make && sudo make install

Assuming you are using the qmlviewer provided with qt-qmlviewer in my home project, you should then be able to run the following:

qmlviewer ../qml-gestures-examples/dashboard/MainWidget.qml

and interact with the example.