User:Jketreno

Revision as of 00:15, 5 January 2011

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

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. As of January 1st 2011, MeeGo Trunk has the correct kernel drivers.
• Qt -- You need a version of Qt that has the XInput2.0 patches applied

NOTE: If you had previously install the multipointtouchplugin, you need to remove it via one of these methods:

zypper remove multipointtouchplugin

or

rm /usr/lib/qt4/plugins/libmultipointtouchplugin.so

If you do not remove that plugin, touch will not work correctly with the XInput2.0 enabled version of Qt.

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

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 mtdev xf86-input-mtev libqt* qt-*

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

Prior to having patches to Qt to add XInput2.0 support, applications had to load a plugin that would connect to the X event queue and process the XInput2.0 events. That is no longer necessary and applications will now just work.

enabling a QML application

For gestures, you should use the qml-gesturearea project from qt-labs to add multi-point touch gestures to your QML applications.

qml-gesturearea

As Frederik Gladhorn indicated during his talk 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

If you are building qml-gesturearea with a version of Qt prior to 4.7.1, you may need to patch it to get it to build:

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

core pointer

If you do nothing, X will default to binding the touch device to the Core Pointer. This means that as you move your finger around, mouse events will be generated, the cursor will move, etc. If X is already running, you can use the xinput utility to "float" the touch device. On the Lenovo S10, running 'xinput list' shows something like the following:

⎡ Virtual core pointer                          id=2    [master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
⎜   ↳ Cando Corporation Cando 10.1 Multi Touch Panel with Controller    id=13   [slave  pointer  (2)]
⎜   ↳ SynPS/2 Synaptics TouchPad                id=16   [slave  pointer  (2)]
...

Looking at the above, you can see the touch device (Cando Corporation...) is device id 13. To float that input device, run:

xinput float 13

and verify that touching the screen no longer moves the mouse pointer.

To perform the following every time you start X, you can add:

Option "SendCoreEvents" "false"

to the InputClass section for the device, for example you can place the following in /usr/share/X11/xorg.conf.d as 60-cando.conf:

Section "InputClass"
        Identifier "Cando Multi Touch Panel"
        MatchVendor "Cando"
        MatchDevicePath "/dev/input/event*"
        Driver "mtev"
        Option "SendCoreEvents" "false"
EndSection

Having the input device disconnected from the Core Pointer, combined with the FocusIn/FocusOut mechanism in the multipointtouchplugin means that window focus will have to be given to windows via an actual mouse pointer (since X will no longer be parsing touch input as an Core pointer input device) or by other means (pressing the application in the app switcher, for example)

meego packages you may need

To perform the above steps on this wiki, a new MeeGo installation may need a few utilities and packages installed:

zypper install git patch xorg-x11-utils-xinput