Onboard and Dwelling during GDM

Introduction

People using Ubuntu 7.10 and that need an onscreen keyboard now have a way to also start it during their GDM session. Moreover, if they cannot click with a hardware button, they can also enable a software click, usually named dwelling. Have a look at the following picture to see onboard and mousetweaks running alongside the Plain interface of GDM (called gdmlogin):

inline:GDMLoginWithOnboardAndDwelling.png

Remark: I have been told that this is currently not possible with the themed greeter (called gdmgreeter), because it is not able to handle other applications using a gui. Consequently the following will be restricted to gdmlogin.

Configuration

For the onscreen keyboard onboard

You have to add a line, that defines what gesture will start onboard, to the gestures configuration file of GDM:

Open a terminal and type:

sudo gedit /etc/gdm/modules/AccessDwellMouseEvents

Add the following line to the opened file:

LBRT I 5000     /usr/bin/onboard --size 400x150 -x 10 -y 10

above the following line that is already in the file that you have to edit:

TBLR I 10000    /usr/bin/gok --login --access-method=directselection

Save and close gedit.

For the dwelling application MouseTweaks

As mousetweaks is not installed by default during the Ubuntu installation, you have to install it yourself; for example by using the Synaptic Package Manager. (At the moment of this writing, it is not included in the Ubuntu repository; but once Ubuntu 7.10 has been released, it should be in the Universe repository.)

Smililar to onboard, add the following line below the line for onboard to the gestures configuration file AccessDwellMouseEvents:

RBLT I 5000     /usr/bin/mousetweaks --enable-dwell --show-ctw

Remark: Mousetweaks needs at-spi to run. But there is currently a bug in GDM: gdmlogin should automatically start at-spi-registryd, but it is not the case. However, if a gesture is defined in the gestures configuration file, it is possible to start it manually with a gesture. Consequently, add the following line below the line for mousetweaks to the gestures configuration file AccessDwellMouseEvents:

RTLB I 5000     /usr/lib/at-spi/at-spi-registryd

Enable Assistive Technology and Set Plain Theme

In order to be able to use the onscreen keyboard onboard and dwelling (there are also other accessibility features) during GDM, you have to previously configure GDM to use its accessibility features. The Login Window under the menu System->Administration of the normal gnome session allows you to perform the appropriate configuration.

• First enable Assistive Technology in the Accessibility tab of the Login Window:

inline:LoginWindowAccessibilityTab.png

• Unfortunately, the accessibility features do not work with the default gdm-theme used by Ubuntu. You have to set gdm to use its Plain theme in the Style menu under the Local tab:

inline:LoginWindowLocalTab.png

How to start onboard

During the GDM session, a background process steadily monitors the pointer to detect determined gestures that are associated with specific programs. On the following picture you can see the gesture that triggers the start of onboard:

inline:gdmlogin-onboard-gesture.png

What matters in the gesture, is:

• what edges of the GDM windows are crossed
• the sequence of the crossed edges
• if the first edge is crossed from outside to inside, or from the inside to the outside
• no more than 5 seconds must elapse between the crossing of one edge and its following edge
• it does not matter if the pointer moves in straight lines (like in the sample above) or in curves; the only thing that matters is the edge crossing

For onboard this means:

• the pointer has to begin by crossing the left edge from the window from the outside to the inside
• then it has to cross the bottom edge from the inside to the outside
• then it has to cross the right edge from the outside to the inside
• finally it has to cross the top edge from the inside to the outside

If no more than 5 seconds did elapse between two border crossings, the onscreen keyboard onboard will appear at the top-left of the screen.

How to start dwelling

It is also possible to start dwelling with a gesture during the GDM session. (provided that Assistive Technology has been enabled for GDM and that the Plain theme is used)

However, the dwelling function needs another background program named at-spi, which in Ubuntu is disabled by default during GDM. Consequently, before starting the dwelling function you have to first start at-spi.

Below, you can see the gesture that starts at-spi and the gesture that starts dwelling:

• Gesture to start mousetweaks for dwelling:

inline:gdmlogin-mousetweaks-gesture.png

• Gesture to start at-spi (only needed as long as it does not start automatically due to a bug) :

inline:gdmlogin-atspi-gesture.png

For explanations about how to interprete the pictures, please have a look at the Starting of onboard above.

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