I was able to display a slider (scale), but I have no idea on how to get its current value. What type is it ? Which method needs to be used to get it ?

So here is the Tcl/Tk, conveniently tested from a win32 command console:

> wish85
(Tcl console opens along with Tk window. In the Tcl console...)
scale .x1 -from 10 -to 100
pack .x1
.x1 get

http://aspn.activestate.com/ASPN/docs/ActiveTcl/8.4/tcl/TkCmd/scale.htm

You could also say:

scale .x1 -variable x1-value

And then make x1-value the text variable of a label and get that working to have some fun. Once (and perhaps not before) all that is working, replicate in LTk.

hth, kenny