Input Method Engine Plug-in for MeeGo

This guide describes how to develop an input method engine plug-in for MeeGo input method framework.
This input method engine plug-in is the implementation for the MImEngineWordsInterface( MImEngineWordsInterface
is the abstract driver class for all prediction/correction engine plug-ins for MeeGo input method framework.)

Step by step approach to develop an input method engine plug-in for MeeGo input method framework.

Create your plug-in

1. Create your own Class by deriving from QObject and MImEngineWordsInterface.
   
2. Try giving dummy implementation to the all the virtual functions of MImEngineWordsInterface.
   
3. While implementing virtual QString driver(); Please return a valid string, that you want to name your plug-in.
   
4. Place the below statement at the end of your .cpp file

   Q_EXPORT_PLUGIN2(plug-in-TARGET-name in your .pro file , Class name that is derived from MImEngineWordsInterface);

5. Add these two lines in your plug-in .pro file so that the plug-in is installed to the right path
   

   target.path += /usr/lib/meego-imengines/drivers/words
   

   INSTALLS += target
   

6. Now compile your project and deploy it. Below link can be referred.

building-meego-applications

Make your plug-in known to framework

Until now, we have created the plug-in and deployed it to the target (QEMU this case).Now we need to tell
the input method framework to start using this plug-in.This could be easily done through a VKB settings page,
as this settings page is not available at present; we need to do it through QEMU console.

1. Access QEMU console is by below command:

   ssh -p 6666 meego@127.0.0.1
   

2. Once you get the console of the target, check for output of

   gconftool-2 -R /meegotouch
   

3. If there is some error related to DISPLAY, you might have to export DISPLAY=:0.0 (In case of QEMU)
   
4. If there are still some errors related DBUS then you have to set DBUS_SESSION_BUS_ADDRESS variable correctly.
   

   Search for the pid of mthemedaemon in your process list
   

   ps ux | awk '/mthemedaemon/ && !/awk/ {print $2}'
   

   get DBUS_SESSION_BUS_ADDRESS value by
   

   cat /proc/$themepid/environ | tr '\0' '\n' | grep DBUS_SESSION_BUS_ADDRESS
   

   Now export the DBUS_SESSION_BUS_ADDRESS value got in the above step
   

   export DBUS_SESSION_BUS_ADDRESS=<<DBUS_SESSION_BUS_ADDRESS value>>
   

   Note: You might not have to do these steps in hardware. These steps I followed while working with QEMU.
   

5. After these steps, you should be able to get the output of

   gconftool-2 -R /meegotouch
   

6. Now set your plug-in name to the below gconf key
   

   gconftool-2 -s -t string /meegotouch/inputmethods/correctionengine "your-plug-in-name"
   

7. Next, kill the already running meego-im-uiserver process and restart it by
   

   /usr/bin/meego-im-uiserver -remote-theme -software -output-level debug
   

   Restarting of the meego-im-uiserver is required, so that the recently modified gconf value is read and the

   plug-in is picked by the input method framework. Now taping on any text field should show the VKB.

[Screen shot taken from netbook QEMU]

Real Implementation

1. Check whether your plug-in is picked by the framework or not.
   
2. Once you are sure that the plug-in is picked by the framework, start giving real implementation to the rest of virtual methods.
   

   Note:Few of them are obsolete and some of them are kept for future usage. Try giving the implementation that suits your requirement.

Test your plug-in

Once you are done with the implementation and want to check for the predictive suggestion/error corrective suggestions,
revisit the gconf settings, which you can set from console.

1. Set below gconf key to true if not yet set to true.

   gconftool-2 -s -t bool /meegotouch/inputmethods/virtualkeyboard/correctionenabled true

2. Set below gconf key to true, if you wish to correct the preedit with the spacebar

   gconftool-2 -s -t bool /meegotouch/inputmethods/virtualkeyboard/correctwithspace true

   
   

   [Screen shot taken from tablet QEMU while editing]

3. If you want to see multiple keyboard layout which can be easily switched by swipe right-to-left/left-to-right on the VKB.
   

   gconftool-2 --type list --list-type string -s /meegotouch/inputmethods/virtualkeyboard/layouts

   [en_gb.xml,de.xml,en_gb.xml,ar.xml,cs.xml,da.xml,es.xml,fi.xml,fr.xml]
   

Ideally for QEMU; below gconf key should be set false. Same holds true if any device does not support multitouch.

gconftool-2 -s -t bool /meegotouch/inputmethods/multitouch/enabled false

Hope this step by step post will help those, who want to write an input method plug-in for MeeGo input method framework.

Source code reference

Source code for an input method plug-in for MeeGo input method framework can be found at http://openadaptxt.svn.sourceforge.net/viewvc/openadaptxt/Branches/Current/OpenAdaptxt2.6/Plugins/Meego/

OpenAdaptxt is an open source community project focused on the development of an open, next-generation text input platform supporting 50+ languages. OpenAdaptxt has been ported to MeeGo.