return location for the X coordinate of the device location, relative to the window origin, or NULL.
return location for the Y coordinate of the device location, relative to the window origin, or NULL.
the gdk.Window under the device position, or NULL.
3.0
Obtains the window underneath device, returning the location of the device in win_x and win_y in double precision. Returns NULL if the window tree under device is not known to GDK (for example, belongs to another application).
As a slave device coordinates are those of its master pointer, This function may not be called on devices of type GDK_DEVICE_TYPE_SLAVE, unless there is an ongoing grab on them, see Device.grab.