This program uses GTDriver in server mode.
When you start it after GTDriver, your digitizer stops
moving the mouse, but you can see the coordinates pair
(expressed in points) of the pen position.
The actual parameter settings are also printed on the
standard output.
This program can be usefull to test if you set the
correct values for Dim X, Dim Y and DPI parameters.
In fact the maximum point values should result
Dim X * DPI in horizontal direction and
Dim Y * DPI in vertical direction.

You can also take a look at the source code to
understand how to write programs that use GTDriver for
their own purpose.